Effect of Modified Huangqi Guizhi Wuwutang on Stress-related IRE1α/CHOP Pathway of Sciatic Nerve Endoplasmic Reticulum in Diabetes Rats / 中国实验方剂学杂志

ObjectiveTo investigate the protective effect of modified Huangqi Guizhi Wuwutang （MHGW） on endoplasmic reticulum stress in the sciatic nerve of diabetes rats based on the pathways of inositol-requiring enzyme 1α （IRE1α） and CCAAT/enhancer-binding protein homologous protein （CHOP）. MethodSixty rats were fed on a high-sugar and high-fat diet for six weeks， followed by intraperitoneal injection of streptozotocin at a dose of 35 mg·kg-1. Random blood glucose levels were measured three days later and rats with a sustained blood glucose level ≥ 16.7 mmol·L-1 were included in study （n=48）. The rats were randomly divided into a model group， an α-lipoic acid group （0.026 8 g·kg-1·d-1）， a high-dose MHGW group （2.5 g·kg-1·d-1）， and a low-dose MHGW group （1.25 g·kg-1·d-1）. Another 10 rats were assigned to the normal group. The intervention lasted for 16 weeks. After 16 weeks， the sciatic nerve structure of the rats in each group was observed under light microscopy using Luxol fast blue （LFB） staining. Transmission electron microscopy was used to observe the ultrastructure of the sciatic nerve. Chemiluminescence method was employed to measure the serum reactive oxygen species （ROS） levels. Western blot and real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） were used to evaluate the expression of p-IRE1α protein， IRE1α mRNA， CHOP protein， and CHOP mRNA in the sciatic nerve of the rats. ResultCompared with the normal group， the model group showed elevated serum ROS levels （P<0.01）. In contrast， the serum ROS levels were significantly reduced in the treatment groups compared with those in the model group （P<0.01）. The sciatic nerve of the model group showed pathological changes compared with that in the normal group， while the treatment groups exhibited improvement in sciatic nerve pathology compared with the model group. The protein expression of p-IRE1α and CHOP in the sciatic nerve significantly increased in the model group as compared with that in the normal group （P<0.01）. However， the treatment groups showed a significant decrease in the protein expression of p-IRE1α and CHOP in the sciatic nerve compared with the model group （P<0.05， P<0.01）. Furthermore， compared with the normal group， the model group showed upregulated mRNA expression of IRE1α and CHOP in the sciatic nerve （P<0.01）， while the treatment groups exhibited a significant decrease in the mRNA expression of IRE1α and CHOP compared with the model group （P<0.01）. ConclusionMHGW can alleviate endoplasmic reticulum stress-induced cell apoptosis and improve the structure and function of the sciatic nerve in diabetes rats by inhibiting the expression of IRE1α/CHOP pathway-related proteins and mRNA， thereby preventing and treating peripheral neuropathy in diabetes.

Research progress of IRE1α inhibitors / 药学学报

Inositol requiring enzyme 1 alpha (IRE1α), a widespread transmembrane protein in mammals, is an endoplasmic reticulum stress (ER stress) receptor. Among the three signaling pathways of the unfolded protein response (UPR), the IRE1α pathway is the most conservative. And there is a growing body of evidence that the occurrence and development of tumors is closely related to the over-expression of IRE1α. Therefore, the study of the IRE1α inhibitors is of great significance to the discovery of new anti-tumor drugs and has been attracting more and more attention. In the hope of providing ideas for the research of targeting IRE1α for cancer therapy, this paper reviewed the data of representative IRE1α inhibitors, including inhibitory activity, the mechanism of action, structural characteristics, and so on.

IRE1α deficiency impairs autophagy in chondrocytes by upregulating calcium homeostasis endoplasmic reticulum protein / 南方医科大学学报

OBJECTIVE@#To explore the mechanism by which inositol-requiring enzyme-1α (IRE1α) regulates autophagy function of chondrocytes through calcium homeostasis endoplasmic reticulum protein (CHERP).@*METHODS@#Cultured human chondrocytes (C28/I2 cells) were treated with tunicamycin, 4μ8c, rapamycin, or both 4μ8c and rapamycin, and the expressions of endoplasmic reticulum (ER) stress- and autophagy-related proteins were detected with Western blotting. Primary chondrocytes from ERN1 knockout (ERN1 CKO) mice and wild-type mice were examined for ATG5 and ATG7 mRNA expressions, IRE1α and p-IRE1α protein expressions, and intracellular calcium ion content using qPCR, Western blotting and flow cytometry. The effect of bafilomycin A1 treatment on LC3 Ⅱ/LC3 Ⅰ ratio in the isolated chondrocytes was assessed with Western blotting. Changes in autophagic flux of the chondrocytes in response to rapamycin treatment were detected using autophagy dual fluorescent virus. The changes in autophagy level in C28/I2 cells overexpressing CHERP and IRE1α were detected using immunofluorescence assay.@*RESULTS@#Tunicamycin treatment significantly up-regulated ER stress-related proteins and LC3 Ⅱ/LC3 Ⅰ ratio and down-regulated the expression of p62 in C28/I2 cells (P < 0.05). Rapamycin obviously up-regulated LC3 Ⅱ/LC3 Ⅰ ratio (P < 0.001) in C28/I2 cells, but this effect was significantly attenuated by co-treatment with 4μ8c (P < 0.05). Compared with the cells from the wild-type mice, the primary chondrocytes from ERN1 knockout mice showed significantly down-regulated mRNA levels of ERN1 (P < 0.01), ATG5 (P < 0.001) and ATG7 (P < 0.001), lowered or even lost expressions of IRE1α and p-IRE1α proteins (PP < 0.01), and increased expression of CHERP (P < 0.05) and intracellular calcium ion content (P < 0.001). Bafilomycin A1 treatment obviously increased LC3 Ⅱ/ LC3 Ⅰ ratio in the chondrocytes from both wild-type and ERN1 knockout mice (P < 0.01 or 0.05), but the increment was more obvious in the wild-type chondrocytes (P < 0.05). Treatment with autophagy dual-fluorescence virus resulted in a significantly greater fluorescence intensity of LC3-GFP in rapamycin-treated ERN1 CKO chondrocytes than in wild-type chondrocytes (P < 0.05). In C28/I2 cells, overexpression of CHERP obviously decreased the fluorescence intensity of LC3, and overexpression of IRE1α enhanced the fluorescence intensity and partially rescued the fluorescence reduction of LC3 caused by CHERP.@*CONCLUSION@#IRE1α deficiency impairs autophagy in chondrocytes by upregulating CHERP and increasing intracellular calcium ion content.

Effect of Huangqi Guizhi Wuwutang on Diabetic Peripheral Neuropathy in MKR Mice via Regulating Endoplasmic Reticulum Stress / 中国实验方剂学杂志

ObjectiveTo investigate the mechanism of Huangqi Guizhi Wuwutang （HQGZWWT） in the treatment of diabetic peripheral neuropathy （DPN） in MKR mice via regulating endoplasmic reticulum （ER） stress. MethodThirty-two 8-week-old MKR mice （half were male and half were female） were fed with a high-fat diet for four weeks， and then 1% streptozotocin （STZ） was injected intraperitoneally for five days. After the blood glucose was stabilized， the mice were housed in the cage covered with ice bags for another one hour stimulation per day for four weeks. Mice with fasting blood glucose （FBG） value ≥11.1 mmol·L-1 were randomly divided into model group ， Huangqi Guizhi Wuwutang in original dosage group （30 g·kg-1·d-1）， Huangqi Guizhi Wuwutang in formula dosage group （6.25 g·kg-1·d-1）， and positive drug group （mecobalamin tablets， 0.17 mg·kg-1·d-1）. Another eight MKR mice of the same age were set as blank group and eight FVB mice were normal group. After four weeks of intragastric administration in each group， the change in FBG was tested， and hematoxylin and eosin （HE） staining and transmission electron microscope were used for observing the morphology of sciatic nerve tissue. In addition， the expression of c-Jun N-terminal kinase （JNK）， phosphorylated c-Jun N-terminal kinase （p-JNK） and inositol requiring enzyme 1α （IRE1α） proteins was determined by immunohistochemical test and Western blot （WB）. ResultCompared with the conditions in the normal group and blank group， the time of paw withdrawal， paw licking and tail flick in the model group was shortened （P<0.01）， and the conduction velocity of sciatic nerve was decreased （P<0.01）. Compared with the conditions in the model group， the behavioral and functional indicators were improved by HQGZWWT （P<0.05，P<0.01）. The immunohistochemical test revealed the JNK expression was elevated in the model group compared with the conditions in the normal group and blank group （P<0.05）， while that was lowered by HQGZWWT compared with the condition in the model group （P<0.05）. However， there was no difference among the treatment groups. According to the WB， the expression of IRE1α and p-JNK in the model group was enhanced compared with the conditions in the normal group and blank group （P<0.05，P<0.01）， while that was decreased by HQGZWWT compared with the condition in the model group （P<0.05，P<0.01）. No difference was observed between the HQGZWWTO and HQGZWWTF groups. ConclusionHQGZWWT can improve the neurophysiological function and pathological damage of sciatic nerve， which may be related to its delaying the ER stress response of sciatic nerve.

Role of inositol-requiring kinase 1α/X-box binding protein 1 in airway mucus secretion induced by neutrophil elastase / 上海交通大学学报（医学版）

Objective: To explore the effect of endoplasmic reticulum stress (ERS) on neutrophil elastase (NE) induced mucin 5AC (MUC5AC) production in human airway epithelial cells. Methods: HBE16 airway epithelial cells were cultured and pretreated with reactive oxygen species (ROS) inhibitor N-acetylcysteine (NAC) or ERS inhibitor 4-phenylbutyrate (4-PBA), or transfected with small interfering RNA (siRNA) against inositolrequiring kinase 1α (IRE-1α) or X-box binding protein 1 (XBP-1), respectively before incubation with NE. NE group and blank control group were also set up. ROS production was assayed by detection kit; expression of glucose-regulated protein 78 (GRP78), phosphorylated protein kinase R-like endoplasmic reticulum kinase (pPERK), activating transcription factor 6 (ATF6), phosphorylated IRE-1α (pIRE-1α), and XBP-1 protein was detected by Western blotting; spliced XBP-1 (XBP-1s) mRNA was measured by real-time PCR; levels of MUC5AC protein in culture supernatant and cytoplasm were assayed by ELISA and immunofluorescence. Results: There was an obvious increase of ROS production with strong elevation of GRP78, ATF6, pPERK, and pIRE-1α protein in NE group cells after 24 h, compared with blank control group (P<0.05). The protein and mRNA of XBP-1s, and MUC5AC production also increased obviously (P<0.05). NAC and 4-PBA reduced ERS-related protein expression and MUC5AC production and secretion (P<0.05). Further studies showed that MUC5AC secretion was also blunted by IRE-1α siRNA or XBP-1 siRNA, accompanied with decreased expression of XBP-1s mRNA and protein (P<0.05). Conclusion: NE induces ERS by producing ROS, and increases MUC5AC protein production and secretion; IRE-1α/XBP-1 play a certain role in this process.

Anti-lung cancer mechanisms of diterpenoid tanshinone via endoplasmic reticulum stress-mediated apoptosis signal pathway / 中国中药杂志

At present, lung cancer ranks second and first respectively in the incidence and the mortality among malignant tumors. It is urgent to find new effective anti-lung cancer drugs with less side effects and relatively defined mechanisms. Endoplasmic reticulum stress (ERS)-mediated apoptosis pathway is an effective way to promote tumor cell apoptosis; diterpenoid tanshinone (DT), an effective part separated from Salviae Miltiorrhizae Radix et Rhizoma, was found to have an anti-lung cancer effect in previous studies via ERS-induced PERK-EIF2α pathway. In this paper, human lung adenocarcinoma PC9 cell line and nude mouse transplantation tumor model were applied to verify the anti-lung cancer effect of DT in vivo and in vitro, and illuminate the potential mechanism via ERS induced IRE1α/caspase 12 apoptosis pathway. The results showed that in vivo, DT could promote PC9 cell apoptosis in a concentration-dependent manner, up-regulate Bip, IRE1 and TRAF2 protein expressions in tumor tissue, reduce tumor weight and alleviate bodyweight loss. In vitro, DT inhibited the proliferation of PC9 cell line in a concentration-dependent manner, and destroyed the structure of mitochondria in PC9 cell, promoted Bax, IRE1α, Bip, TRAF2 and caspase 12 protein expressions, lower Bcl-2 protein expression in a time-dependent manner. DT shows a good effect on anti-lung cancer both in vivo and in vitro. The mechanism is related to the activation of ERS-induced IRE1α/caspase 12 apoptosis pathway and the promotion of cell apoptosis. ERS-mediated apoptosis pathway may be an important target of DT on anti-lung cancer.

Study on mechanism of NOXs in liver fibrosis / 中国药理学通报

Nicotinamide adenine dinucleotide phosphate oxidase ( NOXs) contributes to the production of reactive oxygen species ( ROS) in liver fibrosis, resulting in the activation of endoplas-mic reticulum stress ( ERS ) and IRE1α-XBP1 signaling path-way. ROS is a series of oxygen metabolites and its derivatives, produced by the single electron reduction of molecular oxygen ( O2 ) , including superoxide anion ( O2- ) , hydroxyl radical (-OH) , hydrogen peroxide ( H2 O2 ) , hypochlorite ion ( OCl-) and so on. They can interact with a large number of molecules, including small inorganic molecules, proteins, lipids, carbohy-drates and nucleic acids, resulting in lipid peroxidation of cell damaging molecules. And as a second messenger, ROS can also affect the proliferation and activation of HSC in liver fibrosis, and induce the hepatocyte apoptosis through a variety of cellular signal transduction. Here we review the current status of the study on the mechanism of NOXs in liver fibrosis.