内质网应激与抑郁症关系的研究进展

内质网（endoplasmic reticulum,ER）是细胞内负责蛋白质合成折叠、Ca2＋储存的主要场所,对应激极为敏感。其功能紊乱时出现错误折叠与未折叠蛋白在腔内聚集以及Ca2＋平衡紊乱的状态,称为内质网应激（endoplasmic reticulum stress,ERS）。ERS在细胞生理病理中发挥重要作用,但其具体作用机制目前尚未清楚。     

内质网应激与肝脏疾病

内质网在细胞内分布广泛,是细胞内蛋白质、脂类和糖类合成的重要场所,是细胞内钙离子的储存场所,与物质运输、交换等作用密切相关。内质网稳态失衡会诱导内质网应激(Endoplasmic reticulum stress,ERS),持久应激会导致细胞凋亡。多项研究显示内质网应激与多种肝脏疾病密切相关。本文就内质网应激与肝脏疾病发病机制作一综述。     

内质网应激

内质网应激表现为内质网腔内错误折叠与未折叠蛋白聚集以及Ca^2 平衡紊乱,可激活未折叠蛋白反应、内质网超负荷反应和caspase-12介导的凋亡通路等信号途径,既能诱导糖调节蛋白(glucose-regulated protein 78kD,GRP78)、GRP94等内质网分子伴侣表达而产生保护效应,亦能独立地诱导细胞凋亡。内质网应激直接影响应激细胞的转归,如适应、损伤或凋亡。     

内质网应激与心脏疾病

内质网是细胞内蛋白质合成折叠、Ca2+储存和脂质合成的重要部位.内质网稳态的破坏将导致大量错误或者未折叠蛋白质在内质网中的聚集,通过相应的信号通路,引起一系列的细胞反应,即内质网应激.内质网应激参与心脏的发育和多种心脏疾病的发生发展,包括心肌缺血和再灌注损伤、心肌病、心力衰竭等.内质网应激可能是研究心血管疾病发病机制和防治措施的新靶点.     

硫化氢与内质网应激的相关关系

<正>内质网(Endoplasmic reticulum,ER)是真核细胞中一种重要的细胞器,它的主要功能是参与蛋白质合成,折叠和分泌。如果ER的功能受损、紊乱,继而会导致细胞一系列的病理生理变化,称为内质网应激(Endoplasmic reticulum stress,ERS)~([1])。ERS诱导一系列疾病的产生,包括动脉粥样硬化~([2]),神经退行性疾病~([3])和应激疾病~([4])。以往的研究只发现硫化氢(Hydrogen sulfide,H2S)是一种有毒气体,而且具     

内质网应激与帕金森病

内质网是细胞内最重要的细胞器之一,内质网功能与细胞状态密切相关。异常蛋白在内质网的堆积、胆固醇代谢异常、钙代谢紊乱等均能引起内质网应激。内质网应激在细胞生理病理中发挥重要作用。研究表明:内质网应激与神经退行性疾病,如帕金森病密切相关。该文简单概述了内质网应激与帕金森病之间的关系。     

疱疹病毒与内质网应激

内质网是分泌型蛋白和膜蛋白折叠及翻译后修饰的主要场所.病毒感染所引起的宿主细胞内环境的改变可使细胞或病毒的未折叠和/或错误折叠蛋白在内质网中大量聚集,使内质网处于生理功能紊乱的应激状态.为了缓解这种应激压力,细胞会启动未折叠蛋白反应(UPR),并通过一系列分子的信号转导维持内质网稳态;同时病毒也会通过对UPR的精密调控...     

血管内皮细胞内质网应激

内质网是调控细胞内膜型/分泌型蛋白质合成、钙稳态和细胞凋亡的重要细胞器,多种因素影响内质网稳态、触发内质网应激。适当的内质网应激通过激活未折叠蛋白反应促进内质网紊乱的恢复,但过度内质网应激触发内质网相关凋亡途径,参与多种疾病的发生。血管内皮细胞具有高度发达的内质网,对内质网应激非常敏感,本文综述血管内皮细胞内质网应激反应及其在血管损伤相关疾病中的作用。     

内质网应激与糖尿病动脉粥样硬化

动脉粥样硬化是糖尿病常见的并发症,80%的糖尿病患者死于动脉粥样硬化。近年来内质网应激在糖尿病动脉粥样硬化发生、发展过程中的作用受到了广泛关注。本文就内质网应激及其在糖尿病促发动脉粥样硬化中的作用机制作一概述。     

内质网应激与肝细胞脂类代谢

肝细胞担负大量的代谢功能,包括脂肪酸的合成与类固醇的代谢。内质网应激反应（ERstressresponse）作为内质网中特殊的机制用以保证内质网内部的稳态和功能正常。有研究指出内质网应激诱导的信号通路及其通路上的关键蛋白参与肝细胞的脂类代谢过程。本文主要讨论内质网应激反应影响肝细胞脂类代谢的机制,以及内质网应激与脂类代谢紊乱疾病的相关性。     

Endoplasmic reticulum stress and kidney dysfunction

Chronic kidney disease (CKD) affects millions of persons worldwide and constitutes a major public health problem. Therefore, understanding the molecular basis of CKD is a key challenge for the development of preventive and therapeutic strategies. A major contributor to chronic histological damage associated with CKD is acute kidney injury (AKI). At the cellular level, kidney injuries are associated with microenvironmental alterations, forcing cells to activate adaptive biological processes that eliminate the stressor and generate alarm signals. These signalling pathways actively participate in tissue remodelling by promoting inflammation and fibrogenesis, ultimately leading to CKD. Many stresses that are encountered upon kidney injury are prone to trigger endoplasmic reticulum (ER) stress. In the kidney, ER stress both participates in acute and chronic histological damages, but also promotes cellular adaptation and nephroprotection. In this review, we will discuss the implication of ER stress in the pathophysiology of AKI and CKD progression, and we will give a critical analysis of the current experimental and clinical evidence that support ER stress as a mediator of kidney damage.     

Endoplasmic reticulum proteostasis impairment in aging

Perturbed neuronal proteostasis is a salient feature shared by both aging and protein misfolding disorders. The proteostasis network controls the health of the proteome by integrating pathways involved in protein synthesis, folding, trafficking, secretion, and their degradation. A reduction in the buffering capacity of the proteostasis network during aging may increase the risk to undergo neurodegeneration by enhancing the accumulation of misfolded proteins. As almost one‐third of the proteome is synthetized at the endoplasmic reticulum (ER), maintenance of its proper function is fundamental to sustain neuronal function. In fact, ER stress is a common feature of most neurodegenerative diseases. The unfolded protein response (UPR) operates as central player to maintain ER homeostasis or the induction of cell death of chronically damaged cells. Here, we discuss recent evidence placing ER stress as a driver of brain aging, and the emerging impact of neuronal UPR in controlling global proteostasis at the whole organismal level. Finally, we discuss possible therapeutic interventions to improve proteostasis and prevent pathological brain aging.     

Neuregulin‐1 protects myocardial cells against H2O2‐induced apoptosis by regulating endoplasmic reticulum stress

Neuregulin‐1 (NRG‐1) is a stress‐mediated growth factor secreted by cardiovascular endothelial cells and provides the protection to myocardial cells, but the underlying mechanisms are not fully understood. This study aimed to demonstrate that NRG‐1 protects myocardial cells exposed to oxidative damage by regulating endoplasmic reticulum (ER) stress. Neonatal rat cardiac myocytes (NRCMs) were isolated and treated with H₂O₂ as a cellular model of ER stress. NRCMs were pretreated with different concentrations of NRG‐1. We found that NRG‐1 increased the viability and reduced the apoptosis of NRCMs treated by H₂O₂. Moreover, NRG‐1 reduced lactate dehydrogenase level, increased superoxide dismutase activity and decreased malondialdehyde content in NRCMs treated by H₂O₂. Finally, we demonstrated that NRG‐1 alleviated ER stress and decreased CHOP and GRP78 protein levels in NRCMs treated by H₂O₂. Taken together, these data indicate that NRG‐1 relieves oxidative and ER stress in NRCMs and suggest that NRG‐1 is a promising agent for cardioprotection. Copyright © 2014 John Wiley & Sons, Ltd.     

Endoplasmic reticulum stress induces retinal endothelial permeability of extracellular-superoxide dismutase

Abstract

The aim of this study was to determine the reasons why the intravitreal level of extracellular-superoxide dismutase (EC-SOD) increases in proliferative diabetic retinopathy patients by the investigation of two possibilities: first, change of EC-SOD expression in the retina; and secondly, leakage of EC-SOD through the endothelial monolayer by the treatment with endoplasmic reticulum (ER) stress inducers because ER stress is known to be involved in the vascular impairment in diabetic retinopathy. Intravitreous injection of tunicamycin in mice increased the permeability of tracer dye across retinal blood vessels while the retinal EC-SOD mRNA level was not changed. The leakage of EC-SOD through the retinal endothelial cell layer was elevated by the treatment with thapsigargin or tunicamycin. The expression of claudin-5 was significantly decreased by the treatment with the ER stress inducers. These phenomena were significantly suppressed by the pre-treatment of endothelial cells with a chemical chaperone 4-phenylbutyric acid. Our observations suggest that ER stress leads to the down-regulation of claudin-5 among tight junction proteins and may induce the elevation of endothelial permeability and leakage of EC-SOD into the vitreous body.     

Endoplasmic reticulum stress induced by tunicamycin and thapsigargin protects against transient ischemic brain injury

Transient cerebral ischemia leads to endoplasmic reticulum (ER) stress. However, the contributions of ER stress to cerebral ischemia are not clear. To address this issue, the ER stress activators tunicamycin (TM) and thapsigargin (TG) were administered to transient middle cerebral artery occluded (tMCAO) mice and oxygen-glucose deprivation-reperfusion (OGD-Rep.)-treated neurons. Both TM and TG showed significant protection against ischemia-induced brain injury, as revealed by reduced brain infarct volume and increased glucose uptake rate in ischemic tissue. In OGD-Rep.-treated neurons, 4-PBA, the ER stress releasing mechanism, counteracted the neuronal protection of TM and TG, which also supports a protective role of ER stress in transient brain ischemia. Knocking down the ER stress sensor Eif2s1, which is further activated by TM and TG, reduced the OGD-Rep.-induced neuronal cell death. In addition, both TM and TG prevented PARK2 loss, promoted its recruitment to mitochondria, and activated mitophagy during reperfusion after ischemia. The neuroprotection of TM and TG was reversed by autophagy inhibition (3-methyladenine and Atg7 knockdown) as well as Park2 silencing. The neuroprotection was also diminished in Park2^+/? mice. Moreover, Eif2s1 and downstream Atf4 silencing reduced PARK2 expression, impaired mitophagy induction, and counteracted the neuroprotection. Taken together, the present investigation demonstrates that the ER stress induced by TM and TG protects against the transient ischemic brain injury. The PARK2-mediated mitophagy may be underlying the protection of ER stress. These findings may provide a new strategy to rescue ischemic brains by inducing mitophagy through ER stress activation.     

Endoplasmic reticulum stress induces the phosphorylation of small heat shock protein, Hsp27

There are several reports describing participation of small heat shock proteins (sHsps) in cellular protein quality control. In this study, we estimated the endoplasmic reticulum (ER) stress-induced response of Hsp27 and alphaB-crystallin in mammalian cells. Treatment targeting the ER with tunicamycin or thapsigargin induced the phosphorylation of Hsp27 but not of alphaB-crystallin in U373 MG cells, increase being observed after 2-10 h and decline at 24 h. Similar phosphorylation of Hsp27 by ER stress was also observed with U251 MG and HeLa but not in COS cells and could be blocked using SB203580, an inhibitor of p38 MAP kinase. Other protein kinase inhibitors, like G?6983, PD98059, and SP600125, inhibitors of protein kinase C (PKC), p44/42 MAP kinase, and JNK, respectively, were without major influence. Prolonged treatment with tunicamycin but not thapsigargin for 48 h caused the second induction of the phosphorylation of Hsp27 in U251 MG cells. Under these conditions, the intense perinuclear staining of Hsp27, with some features of aggresomes, was observed in 10%-20% of the cells.     

Genetic factors and epigenetic factors for autism: Endoplasmic reticulum stress and impaired synaptic function

The molecular pathogenesis of ASD (autism spectrum disorder), one of the heritable neurodevelopmental disorders, is not well understood, although over 15 autistic‐susceptible gene loci have been extensively studied. A major issue is whether the proteins that these candidate genes encode are involved in general function and signal transduction. Several mutations in genes encoding synaptic adhesion molecules such as neuroligin, neurexin, CNTNAP (contactin‐associated protein) and CADM1 (cell‐adhesion molecule 1) found in ASD suggest that impaired synaptic function is the underlying pathogenesis. However, knockout mouse models of these mutations do not show all of the autism‐related symptoms, suggesting that gain‐of‐function in addition to loss‐of‐function arising from these mutations may be associated with ASD pathogenesis. Another finding is that family members with a given mutation frequently do not manifest autistic symptoms, which possibly may be because of gender effects, dominance theory and environmental factors, including hormones and stress. Thus epigenetic factors complicate our understanding of the relationship between these mutated genes and ASD pathogenesis. We focus in the present review on findings that ER (endoplasmic reticulum) stress arising from these mutations causes a trafficking disorder of synaptic receptors, such as GABA (γ‐aminobutyric acid) B‐receptors, and leads to their impaired synaptic function and signal transduction. In the present review we propose a hypothesis that ASD pathogenesis is linked not only to loss‐of‐function but also to gain‐of‐function, with an ER stress response to unfolded proteins under the influence of epigenetic factors.