Objective PERK/elF2/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 th...Objective PERK/elF2/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/elF2a/CHOP signaling pathway in vascular endothelial cells. Methods The effects of ox-LDL on PERK and p-elF2a protein expression of primary human umbilical vein endothelial cells （HUVECs） were investigated by Western blot analysis. PERK gene silencing and selective elF2a phosphatase inhibitor, salubrinal were used to inhibit the process of ox-LDL induced endothelial cell apoptosis, caspase-3 activity, and CHOP mRNA level. Results Ox-LDL treatment significantly increased the expression of PERK, PERK-mediated inactivation of elF2a 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 elF2a phosphatase inhibitor, salubrinal. Conclusion This study provides the first evidence that ox-LDL induces apoptosis in vascular endothelial cells mediated largely via the PERK/elF2a/CHOP ER-stress pathway. It adds new insights into the molecular mechanisms underlying the pathogenesis and progression of atherosclerosis.展开更多
Objective This study was conducted to investigate the regulation of endoplasmic reticulum stress on Nrf2 signaling pathway in the kidneys of rats. Methods Rats were divided into twelve groups of six animals each. Some...Objective This study was conducted to investigate the regulation of endoplasmic reticulum stress on Nrf2 signaling pathway in the kidneys of rats. Methods Rats were divided into twelve groups of six animals each. Some groups were pre-administered with bacitracin or tauroursodeoxycholic acid(TUDCA), and all of them were treated with 5-20 μmol/kg cadmium(Cd) for 48 h. The oxidative stress levels were analyzed using kits. The mRNA and protein expression levels of endoplasmic reticulum stress-related factors and Nrf2 signaling pathway-related factors were determined using RT-PCR and western blot. Results Cd exposure resulted in oxidative stress in the kidneys of rats and upregulated the expression of endoplasmic reticulum stress(ERS)-related factors and Nrf2 signaling pathway-related factors, especially at doses of 10 and 20 μmol/kg Cd, and the expression changes were particularly obvious. Moreover, after pretreatment with bacitracin, Cd upregulated the expression of ERS-related factors to a certain extent and, at higher doses, increased the mRNA expression of Nrf2. After pretreatment with TUDCA, Cd reduced the level of ERS to a certain extent; however, at these doses, there were no significant changes in the expression of Nrf2. Conclusion Cadmium can result in ERS and oxidative stress in the kidneys of rats, activate Nrf2, and upregulate the transcriptional expression of phase II detoxification enzymes under these experimental conditions. ERS has a positive regulation effect on Nrf2 signaling pathway but has little effect on the negative regulation of Nrf2 signaling pathway in cadmium toxicity.展开更多
AIM: To investigate the association between endogenous hydrogen sulfide (H<sub>2</sub>S) and portal hypertension as well as its effect on vascular smooth muscle cells.
未折叠蛋白在内质网(endoplasmic reticulum,ER)腔中累积造成ER应激,此时细胞启动未折叠蛋白响应(unfolded protein response,UPR)以恢复蛋白质稳态。目前已知有三种UPR感受器,即IRE1、PERK和ATF6,它们均为ER跨膜蛋白,在ER应激时被激活...未折叠蛋白在内质网(endoplasmic reticulum,ER)腔中累积造成ER应激,此时细胞启动未折叠蛋白响应(unfolded protein response,UPR)以恢复蛋白质稳态。目前已知有三种UPR感受器,即IRE1、PERK和ATF6,它们均为ER跨膜蛋白,在ER应激时被激活并启动下游UPR信号通路。虽然UPR感受器最早是在研究细胞如何应对ER应激时发现的,但它们如何感知ER应激至今未得到完满的回答。随着研究的深入,人们发现UPR的功能不仅限于维持蛋白质稳态,而UPR感受器也不是只对未折叠蛋白累积作出响应。本文对UPR的发现及其经典通路作一介绍,着重阐述目前已知的UPR感受器的激活机制,并就UPR和ER应激关系以及该领域存在的问题进行讨论。展开更多
文摘目的探讨黄芪多糖(astragalus polysaccharide,APS)对2型糖尿病大鼠内质网应激和胰岛素抵抗的治疗作用。方法雄性SPF级SD大鼠44只,利用高脂饲料联合腹腔注射小剂量链脲佐菌素(streptozoto-cin,STZ)复制2型糖尿病模型成功后随机分为4组:正常-组、正常I-APS组、糖尿病组和糖尿病+APS组。饲养期间定期检测动物随机血糖、空腹血糖和Lj服葡萄糖耐量试验(oral glucose tolerance test,OGTT),动物处死后测定肝组织内质网应激的标志蛋白PERK(protein kinase R-l ike ER kinase)磷酸化表达的改变情况。结果①DM+APS组动物在治疗8周后,空腹血糖较DM组显著下降(P<0.01),OGTT各时点血糖值较DM组均显著降低(P<0.01);②磷酸化PERK的表达在DM组较C组显著增加(P<0.01);但在DM+APS组的表达较DM组明显减少(P<0.05)。结论①APS可通过减少p-PERK的表达缓解2型糖尿病大鼠的内质网应激;②APS减少2型糖尿病大鼠的内质网应激反应可能是其增加胰岛素敏感性的机制之一。
基金State Key Clinical Specialty Construction Project,China
文摘Objective PERK/elF2/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/elF2a/CHOP signaling pathway in vascular endothelial cells. Methods The effects of ox-LDL on PERK and p-elF2a protein expression of primary human umbilical vein endothelial cells （HUVECs） were investigated by Western blot analysis. PERK gene silencing and selective elF2a phosphatase inhibitor, salubrinal were used to inhibit the process of ox-LDL induced endothelial cell apoptosis, caspase-3 activity, and CHOP mRNA level. Results Ox-LDL treatment significantly increased the expression of PERK, PERK-mediated inactivation of elF2a 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 elF2a phosphatase inhibitor, salubrinal. Conclusion This study provides the first evidence that ox-LDL induces apoptosis in vascular endothelial cells mediated largely via the PERK/elF2a/CHOP ER-stress pathway. It adds new insights into the molecular mechanisms underlying the pathogenesis and progression of atherosclerosis.
文摘目的观察糖络宁对糖尿病周围神经病变(diabetic peripheral neuropathy,DPN)大鼠坐骨神经内质网应激相关PERK-CHOP-Caspase-12通路的调节作用。方法选用8周龄雄性SD大鼠,除空白对照组外,采用高脂饲料致高血脂联合链脲佐菌素腹腔注射诱导高血糖致DPN大鼠模型。将高脂高糖大鼠随机分为模型对照组、阳性药(氧化三甲胺)对照组、糖络宁低剂量组和糖络宁高剂量组,连续给药12周。给药过程中,动态监测大鼠血糖、血脂,确保糖尿病造模成功。12周后采用免疫荧光法检测坐骨神经中葡萄糖调节蛋白(glucose regulatory protein 78k D,GRP78)、C/EBP同源蛋白(C/EBP-homologous protein,CHOP)、蛋白激酶样内质网激酶(PKR-like ER kinase,PERK)、caspase-12和caspase-3的表达。结果与空白对照组比较,模型对照组坐骨神经中GRP78、CHOP、PERK、Caspase-12和Caspase-3的表达均显著升高(P<0.01或P<0.05);与模型对照组比较,糖络宁低剂量组和高剂量组GRP78表达显著升高(P<0.01),CHOP、PERK、Caspase-12和Caspase-3表达明显降低(P<0.01或P<0.05)。结论糖络宁防治DPN的作用机制与调节坐骨神经中内质网应激相关的PERK-CHOP-Caspase-12通路相关蛋白表达而抑制细胞凋亡有关。
基金supported by grants from the Science and Technology Plan Project of Shenzhen City in China [No.JCYJ20140414154847275]
文摘Objective This study was conducted to investigate the regulation of endoplasmic reticulum stress on Nrf2 signaling pathway in the kidneys of rats. Methods Rats were divided into twelve groups of six animals each. Some groups were pre-administered with bacitracin or tauroursodeoxycholic acid(TUDCA), and all of them were treated with 5-20 μmol/kg cadmium(Cd) for 48 h. The oxidative stress levels were analyzed using kits. The mRNA and protein expression levels of endoplasmic reticulum stress-related factors and Nrf2 signaling pathway-related factors were determined using RT-PCR and western blot. Results Cd exposure resulted in oxidative stress in the kidneys of rats and upregulated the expression of endoplasmic reticulum stress(ERS)-related factors and Nrf2 signaling pathway-related factors, especially at doses of 10 and 20 μmol/kg Cd, and the expression changes were particularly obvious. Moreover, after pretreatment with bacitracin, Cd upregulated the expression of ERS-related factors to a certain extent and, at higher doses, increased the mRNA expression of Nrf2. After pretreatment with TUDCA, Cd reduced the level of ERS to a certain extent; however, at these doses, there were no significant changes in the expression of Nrf2. Conclusion Cadmium can result in ERS and oxidative stress in the kidneys of rats, activate Nrf2, and upregulate the transcriptional expression of phase II detoxification enzymes under these experimental conditions. ERS has a positive regulation effect on Nrf2 signaling pathway but has little effect on the negative regulation of Nrf2 signaling pathway in cadmium toxicity.
基金Supported by Specialized Research Fund for the Doctoral Program of Higher Education of China,No.20120142120048Natural Science Foundation of Hubei Province,China,No.2012FFB02308
文摘AIM: To investigate the association between endogenous hydrogen sulfide (H<sub>2</sub>S) and portal hypertension as well as its effect on vascular smooth muscle cells.
文摘未折叠蛋白在内质网(endoplasmic reticulum,ER)腔中累积造成ER应激,此时细胞启动未折叠蛋白响应(unfolded protein response,UPR)以恢复蛋白质稳态。目前已知有三种UPR感受器,即IRE1、PERK和ATF6,它们均为ER跨膜蛋白,在ER应激时被激活并启动下游UPR信号通路。虽然UPR感受器最早是在研究细胞如何应对ER应激时发现的,但它们如何感知ER应激至今未得到完满的回答。随着研究的深入,人们发现UPR的功能不仅限于维持蛋白质稳态,而UPR感受器也不是只对未折叠蛋白累积作出响应。本文对UPR的发现及其经典通路作一介绍,着重阐述目前已知的UPR感受器的激活机制,并就UPR和ER应激关系以及该领域存在的问题进行讨论。
