Résumé
Objective To evaluate the effect of spliced X-box binding protein 1 (XBP1s) on hypoxia/reoxygenation (H/R) injury of mouse renal tubular epithelial cells and unravel underlying mechanism. Methods Mouse renal tubular epithelial cells were divided into adenovirus negative control group (Ad-shNC group), targeted silencing XBP1s adenovirus group (Ad-shXBP1s group), Ad-shNC+H/R group and Ad-shXBP1s+H/R group. The apoptosis level, mitochondrial reactive oxygen activity, mitochondrial membrane potential and mitochondrial calcium ion level were detected in each group. Chromatin immunocoprecipitation followed by sequencing (ChIP-seq) was employed to analyze the binding sites of XBP1s in regulating the inositol 1,4,5-trisphosphate receptor (ITPR) family. The expression levels of XBP1s and ITPR family messenger RNA (mRNA) and protein were determined in each group. Results Compared with the Ad-shNC group, the apoptosis level was higher, mitochondrial reactive oxygen species level was increased, mitochondrial membrane potential was decreased and mitochondrial calcium ion level was elevated in the Ad-shNC+H/R group. Compared with the Ad-shNC+H/R group, the apoptosis level was lower, mitochondrial reactive oxygen species level was decreased, mitochondrial membrane potential was elevated, and mitochondrial calcium ion level was decreased in the Ad-shXBP1s+H/R group (all P<0.05). Compared with the Ad-shNC group, relative expression levels of XBP1s, ITPR1, ITPR2 and ITPR3 mRNAs and proteins were down-regulated in the Ad-shXBP1s group (all P<0.05). Compared with the Ad-shNC group, relative expression levels of XBP1s, ITPR1, ITPR2 and ITPR3 proteins were up-regulated in the Ad-shNC+H/R group. Compared with the Ad-shNC+H/R group, relative expression levels of XBP1s, ITPR1, ITPR2 and ITPR3 were down-regulated in the Ad-shXBP1s+H/R group (all P<0.05). ChIP-seq results showed that XBP1s could bind to the promoter and exon of ITPR1, the exon of ITPR2, and the exon of ITPR3. Conclusions XBP1s may affect mitochondria-associated endoplasmic reticulum membrane structure and function by directly regulating ITPR transcription and translation. Down-regulating XBP1s may inhibit ITPR expression and mitigate mitochondrial damage.
Résumé
Objective:To evaluate the role of 1, 4, 5-inositol triphosphate receptor (IP3R) in necroptosis of hippocampal neurons induced by sevoflurane anesthesia in aged rats.Methods:Sixty healthy male Sprague-Dawley rats, aged 18 months, weighing 500-600 g, were divided into 3 groups ( n=20 each) using a random number table method: control group (group C), sevoflurane anesthesia group (group S) and sevoflurane anesthesia + IP3R antagonist group (group S+ I). S and S+ I groups inhaled 2% sevoflurane for 5 h. In group S+ I, IP3 receptor antagonist 2-APB 3 mg/kg was intraperitoneally injected at 10 min before sevoflurane inhalation, and the equal volume of dimethyl sulfoxide was intraperitoneally injected in group C and group S. Morris water maze test was used to test the cognitive function on the day after the end of sevoflurane anesthesia.Then the animals were sacrificed and the brain tissues were obtained for microscopic examination of the pathological changes after HE staining and Nissl staining (with a light microscope) and for determination of the free calcium concentration ([Ca 2+ ] i) and rate of necroptosis of hippocampal neurons (by flow cytometry) and expression of IP3R, receptor-interacting protein kinase-1 (RIPK1), receptor-interacting protein kinase-3 (RIPK3) and phosphorylated mixed lineage kinase domain-like protein (p-MLKL) (by Western blot). Results:Compared with group C, the escape latency was significantly prolonged, the times of crossing the platform were reduced, the time of staying at the target quadrant was shortened, the [Ca 2+ ] i and necroptosis rate of hippocampal neurons were increased, and the expression of IP3R, RIPK1, RIPK3 and p-MLKL in hippocampal neurons was up-regulated in group S and group S+ I ( P<0.05). Compared with group S, the escape latency was significantly shortened, the times of crossing the platform were increased, the time of staying at the target quadrant was prolonged, the [Ca 2+ ] i and necroptosis rate of hippocampal neurons were decreased, and the expression of IP3R, RIPK1, RIPK3 and p-MLKL in hippocampal neurons was down-regulated in group S+ I ( P<0.05). Conclusions:The mechanism by which sevoflurane induces cognitive dysfunction may be related to the imbalance of calcium homeostasis caused by activation of IP3R and thus inducing programmed necrosis in aged rats.
Résumé
Objective To investigate the changes of inositol 1,4,5-triphosphate receptor typeⅠ(IP3RⅠ)expression in the myocardial tissue of rats with endotoxic shock and probe the possible mechanisms of myocardial depression.Methods Thirty-three male Wistar rats were divided into four groups:control group (n=6) were injected normal saline(4ml/kg),and the other 3 groups (n=9) were injected endotoxin via femoral vein with a different dose of 10mg/kg,5mg/kg,and the artificial sacrificed group(10mg/kg,the rats were sacrificed when the mean arterial pressure was first rapidly decreased,then gradually increased to the normal level).IP3RⅠexpression in the myocardial tissue of rats was detected by immunohistochemistry,Western blot and colloidal gold immunoelectron microscopy technique.Results IP3RⅠexpressions were increased significantly in each group of rats with endotoxic shock than in the control group (P<0.01),and most obviously enhanced in the the artificial sacrificed group.The expression of IP3RⅠwas related to the level of mean arterial pressure.Ectopic expression of IP3RⅠwas observed around the cell membrane of the cardiac myocytes.Conclusion (1)The expression of IP3RⅠenhances in the myocardial tissue of rats with endotoxic shock,and exists ectopic expression.(2) The expression of IP3RⅠwas related to the level of mean arterial pressure.(3) IP3RⅠ may be related to the cardiac contractility and involved in the regulation of mean arterial pressure.