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

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

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

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

Apoptosis ; drug effects ; Cells, Cultured ; Endoplasmic Reticulum Stress ; physiology ; Heat-Shock Proteins ; analysis ; physiology ; Humans ; Insulin Resistance ; Palmitic Acid ; pharmacology ; Podocytes ; drug effects ; pathology

OBJECTIVETo study the role of lipid peroxidation injury and endoplasmic reticulum stress in Al-induced apoptosis.

METHODSNeurons from 0-3 day rats were cultured and treated with different concentrations of AlCl3.6H2O. Morphologic changes of neurons and endoplasmic reticulum were observed under fluorescent and transmission electron microscope; activities of superoxide dismutase (SOD), malondialdehyde (MDA) and ATP enzymes were detected.

RESULTSTypical morphologic changes in neurons apoptosis and endoplasmic reticulum were found under fluorescent and transmission electron microscope; SOD enzyme viability and ATP enzyme viability were significantly increased in the low-dosage group, but reduced in mid and high-dosage group (P < 0.01), whereas MDA levels decreased in the low-dosage group, but increased in mid and high-dosage group (P < 0.01).

CONCLUSIONAluminum may induce neurons apoptosis, and lipid peroxidation injury in endoplasmic reticulum plays an important role in the apoptosis progression.

Aluminum ; toxicity ; Animals ; Apoptosis ; drug effects ; Cells, Cultured ; Endoplasmic Reticulum Stress ; physiology ; Lipid Peroxidation ; physiology ; Neurons ; drug effects ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the effect of emodin on endoplasmic reticulum (ER) stress of pancreatic acinar AR42J cells.

METHODRat pancreatic acinar AR42J cells were cultured in 6-well plates, and divided into the normal control group, the model group (with the final concentration at 1 x 10(-7) mol · L(-1) for cerulean and lipopolysaccharide at 10 mg · L(-1)) and the emodin group (10, 20, 40 μmol · L(-1)). Cells in each group were cultured in three multiple pores for 24 h, and their supernate was removed after cell attachment. The normal control group was added with haploids, the model group was added with the modeling liquid for haploids, and the treatment groups were added with different concentrations of emodin at 15-20 min before the modeling liquid. The cells were continuously cultured for 3 h under 37 °C and 5% CO2. Their intracellular protease and lipase expressions were detected with kits. The cellular morphology was observed under optical microscope. The level of calcium in endoplasmic reticulum was measured under laser confocal microscopy. Western blot assay were used to determine the protein expression of ER-related signaling molecules.

RESULTEmodin could significantly inhibit levels of amylase, lipase and intracellular calcium and ER.

CONCLUSIONEmodin could reduce pancreatic acinar cell injury induced by the combination of cerulean and lipopolysaccharide. Its action mechanism is correlated with the inhibition of intracellular calcium overload and ER stress.

Animals ; Calcium ; metabolism ; Cell Line, Tumor ; Emodin ; pharmacology ; Endoplasmic Reticulum Stress ; drug effects ; Pancreatic Neoplasms ; metabolism ; pathology ; Rats ; Unfolded Protein Response ; drug effects

OBJECTIVE: To find out the pathological change and the toxic mechanism of Chloranthus serratus Roem. et Schalt in mice. METHODS: Mice were intoxicated by oral administration with extracts of Chloranthus serratus Roem. et Schalt followed by pathological, serum biochemical, and coagulation mechanism examination. RESULTS: The LD50 in mice was 41.12 g/kg; All poisoned mice serum BUN and ALT increased markedly; Thrombocyte decreased and coagulation time increased; The organ index of liver, spleen and kidneys increased significantly; The cells of liver, kidney and heart were degeneration and necrosis, There were extensive hyperemia and hemorrhage in many organs. CONCLUSION The experiment suggests that the target organs were liver, kidney, heart and blood vessels; The toxic mechanism was the damage on the mitochondrional, endoplasmic reticulum and coagulation system.
Animals ; Biomarkers/blood* ; Dose-Response Relationship, Drug ; Endoplasmic Reticulum/drug effects* ; Female ; Forensic Pathology ; Kidney/pathology* ; Lethal Dose 50 ; Liver/pathology* ; Magnoliopsida/chemistry* ; Male ; Mice ; Mitochondria, Heart/drug effects* ; Mitochondria, Liver/drug effects* ; Myocardium/pathology* ; Plant Extracts/toxicity* ; Random Allocation

OBJECTIVETo investigate the role of oxidative stress in the endoplasmic reticulum stress-induced apoptosis of alveolar macrophages triggered by quartz dust.

METHODSSeventy-two healthy adult Wistar rats were randomly divided into control group, quartz dust group, quartz dust plus N-acetyl cysteine (NAC) group, and NAC group, with 18 rats in each group. One milliliter of sterile saline (for the control and NAC groups) or 1 ml of saline with 5%ultrafine quartz dust (for dust group and dust plus NAC group) was given to each rat by non-exposed endotracheal infusion. From the second day after dust infusion, rats in dust plus NAC group and NAC group received intragastric administration of NAC (100 mg/kg). In each week, the treatment with NAC lasted for 5 consecutive days, followed by 2 days' interval. For each group, 6 rats were randomly selected on the 14th, 28th, or 56th day after dust exposure; they were sacrificed by bloodletting from the femoral artery, and the lungs were collected. Bronchoalveolar lavage fluid was collected to separate macrophages. The protein expression of caspase-12 in alveolar macrophages, the apoptosis rate and reactive oxygen species (ROS) content of alveolar macrophages, and the protein carbonyl content of alveolar macrophages were determined by Western blot, flow cytometry, and colorimetry, respectively.

RESULTSIncreased protein expression of caspase-12, apoptosis rate, and content of ROS and protein carbonyl were discovered on the 14th day in the dust group, in comparison with the control group (P < 0.05), and the increase lasted till the 28th and 56th days. (P < 0.05). Compared with the dust group, the dust plus NAC group showed significant decreases in the content of ROS on the 14th, 28th, and 56th days (P < 0.05), significant decreases in the content of protein carbonyl on the 28th and 56th days (P < 0.05), and significant decreases in the protein expression of caspase-12 and apoptosis rate (P < 0.05).

CONCLUSIONOxidative stress is potentially involved in the endoplasmic reticulum stress-induced apoptosis of alveolar macrophages triggered by quartz dust. Oxidative damage of protein in the endoplasmic reticulum may play an important role in the process.

Animals ; Caspase 12 ; metabolism ; Dust ; Endoplasmic Reticulum Stress ; drug effects ; Macrophages, Alveolar ; drug effects ; pathology ; Male ; Oxidative Stress ; drug effects ; Protein Carbonylation ; Quartz ; toxicity ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; metabolism

OBJECTIVETo study the effect of arctiin on mouse podocyte epithelial-mesenchymal transition (EMT) induced by advanced oxidation protein products (AOPP).

METHODSMouse podocytes were stimulated by 200 µg/ml AOPP for 24 h in the presence of 50, 100, 200, and 400 µmol/L arctiin. The expressions of α-smooth muscle actin, Grp78 and CHOP were detected using Western blotting.

RESULTThe expressions of α-SMA, Grp78 and CHOP were inhibited by arctiin, showing a dose-dependent effect within a given range of arctiin concentration.

CONCLUSIONAOPP causes endoplasmic reticulum stress to induce EMT of mouse podocytes, and arctiin can decrease EMT by alleviating the stress. This finding sheds light on a new scope of research of renal fibrosis.

Actins ; metabolism ; Advanced Oxidation Protein Products ; adverse effects ; Animals ; Cell Line ; Endoplasmic Reticulum Stress ; drug effects ; Epithelial-Mesenchymal Transition ; drug effects ; Furans ; pharmacology ; Glucosides ; pharmacology ; Heat-Shock Proteins ; metabolism ; Mice ; Podocytes ; metabolism ; pathology ; Transcription Factor CHOP ; metabolism

OBJECTIVETo investigate the effects of telmisartan on endoplasm reticulum (ER) stress signal pathways and cardiomyocyte apoptosis in abdominal aortic banded rats.

METHODSMale SD rats were randomly divided into sham-operated group, abdominal aortic banding group (AAB) and AAB + telmisartan (5 mgxkg(-1)xd(-1) per gavage, beginning at 1 week before AAB for 8 weeks, n = 10 each). Ten weeks post AAB, hemodynamic measurements were performed, whole heart and left ventricular weights were obtained, cardiomyocyte apoptosis was measured by TUNEL method. Myocardial GRP78 and CHOP protein expressions were detected by Western blot and immunohistochemistry.

RESULTSThe ratio of left ventricular weight to body weight, the ratio of heart weight to body weight, left ventricular end diastolic pressure and the apoptosis index were significantly increased while left ventricular end systolic pressure and +/- dp/dt(max) were significantly decreased in AAB group than those in sham-operated group (all P < 0.01), these changes could be significantly attenuated by telmisartan (all P < 0.01). Moreover, myocardial GRP78 and CHOP expressions were significantly upregulated in AAB group than those in sham-operated group and telmisartan could significantly downregulate the increased GRP78, CHOP expressions (all P < 0.01).

CONCLUSIONSIncreased ER stress might be responsible for enhanced cardiomyocyte apoptosis in AAB rats. Telmisartan effectively attenuated the cardiomyocyte apoptosis and cardiac hypertrophy in AAB rats possibly through reducing ER stress.

Animals ; Aorta, Abdominal ; pathology ; Apoptosis ; drug effects ; Benzimidazoles ; pharmacology ; Benzoates ; pharmacology ; Endoplasmic Reticulum ; metabolism ; Heat-Shock Proteins ; metabolism ; Male ; Molecular Chaperones ; metabolism ; Myocytes, Cardiac ; drug effects ; metabolism ; Postoperative Period ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Transcription Factor CHOP ; metabolism

OBJECTIVETo investigate the effect of lonidamine on apoptosis of human breast carcinoma cells MCF-7 and the possible mechanisms.

METHODSMTT assay and colony-forming assay were used to evaluate the growth inhibition induced by lonidamine in breast cancer MCF-7 cells. PI/Annexin-V staining was used to detect the apoptotic cells. The ATP levels in the cells were detected using an ATP assay kit. The expression of glucose regulated protein 78 (GRP78), inhibitor of apoptosis protein (cIAP1) and caspase-8 were analyzed with Western blotting.

RESULTSMTT assay and colony-forming assay showed that 50-250 mmol/L lonidamine caused a time- and concentration-dependent inhibition of MCF-7 cell proliferation. Exposure to increased concentrations of lonidamine resulted in significantly increased apoptosis rate in MCF-7 cells. In MCF-7 cells treated with 50, 150 and 250 mmol/L lonidamine for 5 h, the intracellular ATP levels were lowered to 80.67%, 62.78% and 30.73% of the control level, respectively. Western blotting showed that lonidamine up-regulated the expression of GRP78, down-regulated the expression of cIAP1 and promoted caspase-8 activation as the treatment time extended.

CONCLUSIONLonidamine can inhibit the proliferation and induce apoptosis in MCF-7 cells, and these effects are probably mediated by reducing ATP level, inducing endoplasmic reticulum stress response, down-regulating cIAP1, and promoting caspase-8 activation in the cells.

Apoptosis ; drug effects ; Breast Neoplasms ; metabolism ; pathology ; Caspase 8 ; metabolism ; Cell Proliferation ; Down-Regulation ; Endoplasmic Reticulum Stress ; Heat-Shock Proteins ; metabolism ; Humans ; Indazoles ; pharmacology ; Inhibitor of Apoptosis Proteins ; metabolism ; MCF-7 Cells ; drug effects ; Ubiquitin-Protein Ligases ; metabolism ; Up-Regulation

This study was aimed to explore the effect of bortezomib on the apoptosis and expression of the molecular chaperone BiP in human multiple myeloma cell line NCI-H929 (H929). After treatment of H929 cells with different concentrations of bortezomib for 24 hours, cell apoptosis was assayed by flow cytometry with Annexin V-FITC/PI staining, and the expression levels of BiP mRNA and protein were detected by RT-PCR and Western blotting analysis. The results showed that bortezomib of different concentrations (20, 40 and 80 nmol/L) induced apoptosis of H929 cells in dose-dependent manner, with apoptotic rates (15.73 +/- 0.67)%, (27.83 +/- 1.26)% and (44.17 +/- 2.25)% respectively, which were significantly higher than that in control (1.21 +/- 0.07%) (p < 0.05). Bortezomib-induced up-regulation of BiP mRNA levels was almost on a parallel with BiP protein when compared with control. Under the similar apoptosis-stimulating conditions with apoptotic rates varying from 40% to 50%, expression levels of BiP mRNA and BiP protein induced by the classical endoplasmic reticulum stressor Brefeldin A (500 ng/ml, 24 h) were almost consistent with those by bortezomib (80 nmol/L, 24 h). It is concluded that bortezomib-induced apoptosis in H929 cells correlates closely with endoplasmic reticulum stress.
Apoptosis ; drug effects ; Boronic Acids ; pharmacology ; Bortezomib ; Cell Line, Tumor ; Endoplasmic Reticulum ; drug effects ; metabolism ; Heat-Shock Proteins ; metabolism ; Humans ; Multiple Myeloma ; metabolism ; pathology ; Pyrazines ; pharmacology ; RNA, Messenger ; genetics

Endoplasmic reticulum (ER) stress regulates a wide range of cellular responses including apoptosis, proliferation, inflammation, and differentiation in mammalian cells. In this study, we observed the role of 2-deoxy-D-glucose (2DG) on inflammation of chondrocytes. 2DG is well known as an inducer of ER stress, via inhibition of glycolysis and glycosylation. Treatment of 2DG in chondrocytes considerably induced ER stress in a dose- and time-dependent manner, which was demonstrated by a reduction of glucose regulated protein of 94 kDa (grp94), an ER stress-inducible protein, as determined by a Western blot analysis. In addition, induction of ER stress by 2DG led to the expression of COX-2 protein with an apparent molecular mass of 66-70kDa as compared with the normally expressed 72-74 kDa protein. The suppression of ER stress with salubrinal (Salub), a selective inhibitor of eif2-alpha dephosphorylation, successfully prevented grp94 induction and efficiently recovered 2DG-modified COX-2 molecular mass and COX-2 activity might be associated with COX-2 N-glycosylation. Also, treatment of 2DG increased phosphorylation of Src in chondrocytes. The inhibition of the Src signaling pathway with PP2 (Src tyrosine kinase inhibitor) suppressed grp94 expression and restored COX-2 expression, N-glycosylation, and PGE2 production, as determined by a Western blot analysis and PGE2 assay. Taken together, our results indicate that the ER stress induced by 2DG results in a decrease of the transcription level, the molecular mass, and the activity of COX-2 in rabbit articular chondrocytes via a Src kinase-dependent pathway.
Animals ; Cartilage, Articular/pathology ; Cells, Cultured ; Chondrocytes/drug effects/immunology/*metabolism/pathology ; Cyclooxygenase 2/genetics/*metabolism ; Deoxyglucose/*pharmacology ; Down-Regulation ; Endoplasmic Reticulum/drug effects/*metabolism/pathology ; Glycosylation/drug effects ; Inflammation ; Rabbits ; Signal Transduction/drug effects ; Stress, Physiological/drug effects/immunology ; src-Family Kinases/*metabolism