Objective To investigate whether cigarette smoke promote endoplasmic reticulum associated apoptosis gene Caspase-12 expression. Methods Forty adult male Wistar rats were randomly divided into four groups, ie. group A ( control group) , group B ( exposed to cigarette smoke for two months) ,group C ( exposed to cigarette smoke for four months) , and group D ( exposed to cigarette smoke for four months, then quit smoking for one month) . The COPD rat model was established with passive smoking.Percentage of forced expiratory volume in first 0. 3 second to forced vital capacity ( FEV0. 3 /FVC) and peak expiratory flow ( PEF) were measured. Reverse transcriptase-polymerase chain reaction ( RT-PCR) was used to determine the mRNA expression of Caspase-12. Immunohistochemistry and Western blot were used todetermine the protein expression of Caspase-12. Caspase-12-fluorometric-assay-kit was used to determine Caspase-12 activity. Results The pulmonary function decreased ( P lt; 0. 05) and the lung structure was damaged in the group B compared with the group A. The lung function markedly decreased( P lt; 0. 05) andthe lung structure was obviously damaged in the group C compared with the group B. The pulmonary function had minor improvement( P gt; 0. 05) , and the lung structure injury was also significant in the group D in contrast with the group C. The expression and activity of Caspase-12 were remarkably increased in the group B compared with the group A( P lt; 0. 05) , elevated significantly in the group C compared with the group B ( P lt; 0. 05) , decreased slightly in the group D compared with the group C ( P gt; 0. 05 ) . Conclusion Cigarette smoke promotes the development of COPD by inducing the endoplasmic reticulum associated apoptosis gene Caspase-12 expression.
Objective Endoplasmic reticulum stress (ERS) mediated apoptosis is one of the eukaryotic cellularapoptotic pathways, to investigate the potential role of ERS during myocardium apoptosis in rats with severe burninjury. Methods Sixty-four 7-week-old male Wistar rats, weighing 200-220 g, were randomly divided into 2 groups. Thirtypercentage of total body surface area full-thickness thermal injury was produced in 32 rats of burn group, while sham burn wasproduced in 32 rats of control group. The heart tissues were harvested from 8 rats in each group at 1, 4, 7, and 14 days after burnto observe the changes of myocardium ultrastructure with transmission electron microscope (TEM). Myocardium apoptosis wasdetected with TUNEL assay. The expressions of glucose regulated protein 78 (GRP 78), C/EBP-homologous protein (CHOP),and cleaved Caspase 12 in different pathways of ERS were analysed with Western blot. Results All rats survived during theexperiment. Apoptotic changes of cardiomyocytes were observed in burn group, and the apoptosis index in burn group wassignificantly higher than that in control group at each time point (P lt; 0.05), and it reached peak at 7 days after burn injury(P lt; 0.05). The expressions of myocardial GRP 78, CHOP, and cleaved Caspase 12 showed persistent elevation in burn group.The expressions of GRP 78 and cleaved Caspase 12 in burn group were significantly higher than those in control group at eachtime point (P lt; 0.05), while the expression of CHOP was higher than that in control group at the other time points (P lt; 0.05)except 1st day after burn injury. Conclusion ERS and CHOP, Caspase 12 mediated apoptotic pathway are activated inmyocardium after severe burn injury, and this may be one pathway of myocardium apoptosis.
Objective To realize the research progress of regulating the endoplasmic reticulum stress response to inhibit autophagy in tumor cells. Method The literatures about regulating the endoplasmic reticulum stress response to inhibit autophagy in tumor cells were reviewed. Result In the endoplasmic reticulum stress response induced by the release of calcium and accumulation of unfolded proteins, autophagy can be activated by several pathways, and to regulate physiological and pathological processes. Conclusion Further research about the endoplasmic reticulum stress response in tumor cells need to be done to regulate the response factors to inhibit autophagy.
ObjectiveTo investigate the endoplasmic reticulum stress associated apoptosis gene Caspase-12 expression in paraquat-induced pulmonary fibrosis. Methods30 adult healthy Sprague-Dawley(SD) rats were randomly divided into a nomal control group,two pulmonary fibrosis model groups (intragastrically administered paraquat for 14 days and 28 days,respectively).The model of pulmonary fibrosis was established through intragastrically administering paraquat at the dose of 30 mg/kg.RT-PCR was used to determine the mRNA expression of Caspase-12.Immunohistochemistry was used to determine the protein expression of Caspase-12.HE staining and Masson staining were used to determine the degree of alveolitis and pulmonary fibrosis. ResultsHE staining and Masson staining of lung tissues proved that pulmonary fibrosis model was successfully constructed.The degree of alveolitis and pulmonary fibrosis in the model group was significantly more serious than that in the control group(P<0.01).RT-PCR and Immunohistochemistry results showed that the expression of Caspase-12 were remarkably increased in the pulmonary fibrosis model group(14 d group)(P<0.01),even more elevated in 28 d group compared with the 14 d group. ConclusionThe results demonstrate that the expression of Caspase-12 in paraquat poisoned rats is up-regulated,suggesting endoplasmic reticulum stress plays an important role in paraquat induced-pulmonary fibrosis.
Metabolic memory means if the hyperglycemia can't be controlled at early stage of diabetes, chronic complications such as diabetic retinopathy (DR) will continue to develop even if the blood glucose level maintains normal level at later stage. Oxidative stress plays an important role in the "metabolic memory" of DR, which interacts with the nitrative stress, advanced glycation end products, genetic modification and endoplasmic reticulum stress in the pathogenesis of DR. Further elucidation of the relationship between oxidative stress and "metabolic memory" of DR can open the way for the discovery of novel therapeutic targets to prevent DR progression.
Objective To explore the mechanism of chronic intermittent hypoxia (CIH) on renal damage with normal diet and high-fat diet. Methods Twenty-four healthy male Wistar rats of SPF grade were randomly divided into 4 groups (n=6 in each group), namely group A (normoxia and common diet), group B (normoxia and high fat diet), Group C (CIH and common diet), and group D (CIH and high fat diet). The serum cystatin C (Cys-C) was measured and the renal CHOP protein was detected by immunohistochemistry. The ultrastructural changes of glomeruli and renal tubules were observed under electron microscope. Results The levels of Cys-C in group B, group C and group D were significantly higher than those in group A (P<0.05). The mean density of endoplasmic reticulum stress (ERS) marker protein CHOP in group B, group C and group D was significantly higher than that in group A (P<0.05). Electron microscope revealed focal nuclear pyknosis in the partly renal tubular epithelial cells, sparse and scattered brush border in group B and group C, also revealed nuclear pyknosis in a large number of tubular epithelial cells, sparse and scattered brush border in group D. Conclusion CIH can activate the ERS mediated renal tubular epithelial apoptosis, thus induce ultrastructure changes and damage of kidney.
ObjectiveTo investigate the protective effects and mechanism of selective histone deacetylases 6 (HDAC6) inhibitor 23BB in myoglobin-induced proximal tubular cell lines (HK-2).MethodsHK-2 cells were divided into 5 groups, including control group, myoglobin (200 μmol/L) group, myoglobin (200 μmol/L)+23BB (1.25 nmol/L) group, myoglobin (200 μmol/L)+4-phenylbutyric acid (2 mmol/L) group, and myoglobin (200 μmol/L)+23BB (1.25 nmol/L)+tunicamycin (25 ng/mL) group. Cells were collected at 24 hours after treatment. The endoplasmic reticulum (ER) stress-related gene mRNA level and marker protein expression were evaluated by RT-PCR and Western blotting, including glucose regulated protein 78 (GRP78), C/EBP homology protein (CHOP), inositol-requiring enzyme 1 (IRE1), PKR-like ER kinase (PERK), and activating transcription factor 6.ResultsIn in vitro study, ER stress-related mRNA of GRP78, IRE1α, PERK, and CHOP and marker protein expression of GRP78 and CHOP were found to increase in response to myoglobin treatment. Either administration of 23BB or 4-PBA could alleviate myoglobin-induced these changes.ConclusionThe protective effect of HDAC6 inhibitor 23BB is through the inhibition of myoglobin-induced ER stress in HK-2 cells.
ObjectiveTo explore the mechanism of renal tubular epithelial cell apoptosis induced by endoplasmic reticulum stress in rats with intermittent hypoxia (IH) and the intervention effect of losartan.MethodsSixty SPF grade healthy male SD rats were randomly divided into four groups (15 rats in each group), namely as group A (control group), group B (IH group), group C (IH+losartan group), and group D (IH+saline group). The group C and D were intraperitoneally injected with losartan 30 mg/kg and the same dose of saline 30 minutes daily before the experiment, and then the group B, C and D were placed in the intermittent hypoxia chamber. After 6 weeks of modeling, serum of the rats was sampled to detect the renal function. Hematoxylin-eosin staining was used to observe histomorphological changes of the kidney; transmission electron microscopy was used to observe ultrastructural changes of the kidney; TUNEL was used to detect apoptotic index of the renal tubular epithelial cells; and RT-PCR method was used to detect expressions of caspase-12, JNK and CHOP mRNA in the kidney.ResultsThe differences of renal function among these four groups were statistically significant (all P<0.05). Hematoxylin-eosin staining and transmission electron microscopy showed the histomorphological and ultrastructural changes of the kidneys in group B, C and D compared with group A, and the damages in group B and D were more significant. TUNEL results showed that the apoptotic index of renal tubular epithelial cells in group B and D was significantly higher than that in group A (P<0.01), while that in group C was significantly lower than that in group B and D (all P<0.01). RT-PCR results showed that caspase-12, JNK and CHOP mRNA expressions were significantly higher in group B and D than those in group A (all P<0.01); caspase-12 mRNA expression was significantly lower in group C than that in group B and D (P<0.01; P<0.05); and CHOP mRNA expression was significantly lower in group C than that in group B and D (all P<0.01).ConclusionsIH may induce apoptosis of renal tubular epithelial cells by activating endoplasmic reticulum stress through caspase-12, JNK and CHOP. Losartan has protective effects on the kidney of rats with intermittent hypoxia. Its mechanism may be related to the inhibition of apoptotic pathways mediated by endoplasmic reticulum stress.
Objective To observe the effects of overexpression of polypyrimidine tract binding protein-associated splicing factor (PSF) on the endoplasmic reticulum (ER) oxidative stress damage of human retinal microvascular endothelial cells (hRMEC) under high concentration of 4-hydroxynonenal (4-HNE). MethodsThe logarithmic growth phase hRMEC cultured in vitro was divided into normal group, simple 4-HNE treatment group (simple 4-HNE group), empty plasmid combined with 4-HNE treatment group (Vec+4-HNE group), and PSF high expression combined with 4-HNE treatment group (PSF+4-HNE group). In 4-HNE group, Vec+4-HNE group, and PSF+4-HNE group cell culture medium, 10 μmol/L 4-HNE was added and stimulated for 12 hours. Subsequently, the Vec+4-HNE group and PSF+4-HNE group were transfected with transfection reagent liposome 2000 into pcDNA empty bodies and pcDNA-PSF eukaryotic expression plasmids, respectively, for 24 hours. Flow cytometry was used to detect the effects of 4-HNE and PSF on cell apoptosis. The effect of PSF overexpression on the expression of reactive oxygen species (ROS) in hRMEC was detected by 2', 7'-dichlorodihydrofluorescein double Acetate probe. Western blot was used to detect ER oxide protein 1 (Ero-1), protein disulfide isomerase (PDI), C/EBP homologous transcription factor (CHOP), glucose regulatory protein (GRP) 78, protein kinase R-like ER kinase (PERK)/phosphorylated PERK (p-PERK), and Eukaryotic initiation factor (eIF) 2α/the relative expression levels of phosphorylated eIF (peIF) and activated transcription factor 4 (ATF4) proteins in hRMEC of normal group, 4-HNE group, Vec+4-HNE group, and PSF+4-HNE group. Single factor analysis of variance was performed for inter group comparison. ResultsThe apoptosis rates of the simple 4-HNE group, Vec+4-HNE group, and PSF+4-HNE group were (22.50±0.58)%, (26.93±0.55)%, and (11.70±0.17)%, respectively. The intracellular ROS expression levels were 0.23±0.03, 1.60±0.06, and 0.50±0.06, respectively. The difference in cell apoptosis rate among the three groups was statistically significant (F=24.531, P＜0.05). The expression level of ROS in the Vec+4-HNE group was significantly higher than that in the simple 4-HNE group and the PSF+4-HNE group, with a statistically significant difference (F=37.274, P＜0.05). The relative expression levels of ER Ero-1 and PDI proteins in the normal group, simple 4-HNE group, Vec+4-HNE group, and PSF+4-HNE group were 1.25±0.03, 0.45±0.03, 0.63±0.03, 1.13±0.09, and 1.00±0.10, 0.27±0.10, 0.31±0.05, and 0.80±0.06, respectively. The relative expression levels of CHOP and GRP78 proteins were 0.55±0.06, 1.13±0.09, 0.90±0.06, 0.48±0.04 and 0.48±0.04, 1.25±0.03, 1.03±0.09, 0.50±0.06, respectively. The relative expression levels of Ero-1 (F=43.164), PDI (F=36.643), CHOP (F=42.855), and GRP78 (F=45.275) proteins in four groups were compared, and the differences were statistically significant (P＜0.05). Four groups of cells ER p-pERK/pERK (F=35.755), peIF2 α/ The relative expression levels of eIF (F=38.643) and ATF4 (F=31.275) proteins were compared, and the differences were statistically significant (P＜0.05). ConclusionPSF can inhibit cell apoptosis and ROS production induced by high concentration of 4-HNE, and its mechanism is closely related to restoring the homeostasis of ER and down-regulating the activation level of PERK/eIF2α/ATF4 pathway.
The occurrence and development of myopia is closely related to scleral remodeling. Therefore, in order to effectively prevent and cure myopia, it is very important to clarify the mechanism of scleral remodeling. In recent years, Chinese scholars have found that endoplasmic reticulum stress can regulate the expression of apoptotic proteins through the inositol demand protein-1/X box binding protein-1 pathway in the unfolded protein response, thus it is involved in regulating the state of scleral fibroblasts under hypoxia and regulating the occurrence and development of scleral remodeling. At the same time, some studies have found that inhibiting and knocking out protein kinase RNA-like endoplasmic reticulum kinase and activated transcription factor 6 in endoplasmic reticulum stress can effectively inhibit the growth of ocular axis. This proves that endoplasmic reticulum stress plays an important role in the occurrence and development of scleral remodeling. However, the comprehensive analysis of endoplasmic reticulum stress and scleral remodeling has not been reported at home and abroad. In-depth analysis of the relationship between endoplasmic reticulum and scleral remodeling is of great significance for the follow-up analysis and study of the mechanism of scleral remodeling.