未折叠蛋白反应与炎症性肠病

内质网（ER）是细胞内蛋白折叠修饰组装的场所,由于某种原因使错误折叠蛋白质或未折叠蛋白质在ER内聚集导致稳态失衡、生理功能发生紊乱称为内质网应激（ERS）,当出现ERS时,细胞为了继续存活而发生了一系列适应性反应即“未折叠蛋白反应（UPR）”。研究发现,基因敲除UPR中的关键基因能够自发的形成与人类炎症性肠病（IBD）相似的肠道炎症。本文主要介绍目前对不正确的UPR引起肠道炎症的机制,同时强调内质网应激作为IBD发生发展的一个重要途径。     

内质网应激干预与神经系统疾病治疗前景

内环境稳定是内质网生理功能实现的基础,氧化应激反应、同型半胱氨酸增加、Ca~(2+)稳态失衡引发内质网应激(ERS)。ERS包括未折叠蛋白反应、内质网超负荷反应、胆固醇调节级联反应。目前发现经内质网途径引发的细胞凋亡与多种疾病的发生发展均存在关系。近年来,ERS途径引发细胞凋亡成为医学科研热点,研究ERS、细胞凋亡可以为疾病治疗提供新的思路。     

内质网应激与心肌缺血再灌注损伤

<正>内质网(ER)是胞质参与蛋白质折叠、加工、分泌及调节Ca2+储存、转运的多功能细胞器。内外环境改变可导致ER功能错乱,使其未折叠蛋白聚集、钙稳态破坏,导致内质网应激(ERS),它本身是一种自我保护机制,但过强或过久均会导致细胞死亡,从而对心肌缺血再灌注损伤(I/R)过程中多种反应起调节作用。本文就近年ERS在I/R中的研究进行综述,现报告如下。1内质网应激     

内质网应激与肿瘤细胞的凋亡

内质网（endoplasmic reticulum,ER）是重要的细胞器,是蛋白质合成、折叠、组装和钙离子储存等的场所。多种生理和病理条件下,如缺氧、氧化还原状态的改变等可干扰内质网的功能,并引起未折叠蛋白在ER中堆积,产生内质网应激（endoplasmic reticulum stress,ERS）。虽然ERS可诱导细胞的生存,然而长时间过强的ERS可诱导细胞凋亡,即内质网应激反应性凋亡。     

内质网应激和糖尿病微血管病变关系的研究进展

糖尿病微血管病变是由高糖高脂引起的一组特异性疾病,可累及心肌、肾脏、视网膜、周围神经,是致死致残的主要原因。内质网（endoplasmic reticulum,ER）存在于所有真核细胞,是细胞中合成蛋白质、钙储存、脂质代谢的重要场所。当细胞遭遇高糖、缺氧、炎症、氧化应激、感染等病理因素侵扰时,ER内环境稳态失衡,功能受损,未折叠和错误折叠的蛋白积聚,引发内质网应激（endoplasmic reticulum stress,ERS）。ERS是机体应对蛋白质折叠错误、糖脂代谢异常的自适应调节行为,适度的ERS有助于减轻因糖尿病代谢异常导致的微血管病变,提升糖尿病患者的生活质量。文章综述了近五年内质网应激和糖尿病微血管病变的关系和相关机制研究,旨在为通过调节内质网应激防治糖尿病及其微血管病变提供一定的参考依据。     

未折叠蛋白反应与多发性骨髓瘤的治疗

内质网（endoplasmic reticulum，ER）是真核细胞中负责分泌性蛋白折叠和组装的主要细胞器。当细胞在内外源因素刺激下，ER中未折叠或错误折叠的蛋白增多，出现ER应激（ERstress），继而引发未折叠蛋白反应（unfolded proteinre．sponse，UPR），可以促进分子伴侣等靶基因的转录，减少蛋白质翻译，并通过内质网相关蛋白降解（ER—associated degra．dation，ERAD）途径，将未折叠蛋白经泛素一蛋白酶体系统降解，使细胞在应激状态下存活；     

内质网应激在肺肿瘤中的作用

内质网是细胞的蛋白质加工厂,主要负责蛋白质的合成、折叠和装配。各种生理和病理条件(如缺氧、氧化还原状态的变化)可能会干扰内质网的功能,并导致未折叠蛋白在内质网中积累,导致内质网应激(endoplasmic reticulum stress,ERS)。ERS是细胞抵抗外来不良刺激的一种重要保护机制,也是决定细胞命运的关键。适度的ERS能够促进肺肿瘤细胞生存和转移,过度的ERS则促进肺肿瘤细胞凋亡。多种抗肿瘤药物都可通过加重ERS而促进肺肿瘤细胞凋亡。     

内质网应激介导成骨细胞凋亡在骨溶解骨组织中的作用及机制

背景：磨损微粒能够在体外诱导成骨细胞凋亡,但是发生骨溶解的骨组织中是否也存在成骨细胞的凋亡以及骨组织中的成骨细胞凋亡信号通过何种途径进行传导目前尚不清楚。目的：分析内质网应激反应在骨溶解骨组织中成骨细胞凋亡和骨溶解发生发展中的作用。方法：制备磨损微粒诱导骨溶解动物模型。实验分为4组：空白对照组只接受PBS的刺激;磨损微粒组只接受纳米合金粉末悬液的刺激;内质网应激阳性对照组接受纳米合金粉末＋毒胡萝卜素的刺激;内质网应激抑制组接受纳米合金粉末悬液及造模后当时、造模后1,2,3和5 d分别腹腔注射4-苯基丁酸。通过甲苯胺蓝染色、苏木精-伊红染色和碱性磷酸酶染色观察骨溶解的病理变化;分析骨溶解颅骨组织中成骨细胞分化成熟情况;Western Blot 方法检测骨溶解颅骨组织内内质网应激反应标志蛋白的表达变化;TUNEL 和 Caspase-3免疫组织化学方法检测骨溶解颅骨组织内成骨细胞的凋亡情况。结果与结论：磨损微粒能够在体外诱导小鼠颅骨骨溶解的发生、加重炎症细胞的浸润以及抑制成骨细胞分化成熟,同时磨损微粒还可以上调成骨细胞内质网应激反应标志蛋白以及促进骨溶解骨组织中成骨细胞的凋亡。经内质网应激抑制剂（4-苯基丁酸）的治疗后,骨溶解症状明显缓解,骨侵蚀和炎症浸润显著降低,成骨细胞的分化成熟得到改善,凋亡的成骨细胞急剧减少,内质网应激标志蛋白的表达逐渐减弱。表明内质网应激反应参与骨溶解的形成并在骨溶解的发生发展中发挥重要作用。提示内质网应激可作为一种新的治疗靶点,为临床逆转或治疗骨溶解和无菌性松动提供新的思路和方法。     

内质网与细胞凋亡

内质网是细胞重要的细胞器,参与蛋白质合成、折叠和寡聚化,还参与脂质代谢、类固醇激素的合成、钙的储存等。内质网应激与细胞凋亡密切相关,现就内质网应激反应、内质网Ca^2＋水平的调节、内质网与Bcl-2家族蛋白及其与疾病的关系等方面进行综述。     

氨基酸对内质网应激影响的研究进展

内质网应激(ERS)的发生参与了人体多种疾病的发生、发展。精准、有效的干预和调控ERS成为近年来关注的热点。氨基酸作为构成人体所需蛋白质的营养元素,同时,也是人体内重要的信号传导分子。通过氨基酸对ERS反应的干预和调节很可能是一个重要且未开发的领域,有望成为探求恶性肿瘤、心血管疾病等新防治策略的潜在靶点。因此,该文将近年来氨基酸对细胞ERS反应影响的研究进展作一综述。     

骨骼肌钝挫伤的损伤与修复机制研究进展CSCD

总结骨骼肌钝挫伤的损伤与修复机制,并从肌卫星细胞增殖和分化学说、Ca^(2+)介导的细胞膜修复学说、内质网应激学说以及自噬学说等方面进行阐述。肌再生依赖于周围卫星细胞的分化、增殖来促进骨骼肌再生,从而修复受损肌肉的功能。调控肌卫星细胞成肌分化的相关信号通路主要包括RBP-Jκ/Notch信号、Wnt信号和P13K/Akt/mTOR信号通路。其中Notch信号通路通过调控肌卫星细胞自我更新和分化来维持肌干细胞的稳态。P13K/Akt/mTOR信号通路对肌卫星细胞的成肌分化具有正向调控作用,能够促进骨骼肌再生。然而,当前的研究对Wnt信号通路在成熟骨骼肌再生过程中的作用存在争议,激活Wnt信号通路是否有利于骨骼肌损伤与修复需要更多的研究来进行论证。Ca^(2+)介导细胞膜修复对骨骼肌钝挫伤后肌膜修复、细胞存活至关重要。但是骨骼肌损伤后引起钙泵结构受损或功能下降使Ca^(2+)回收受阻,Ca^(2+)失调通过促进线粒体的活性氧(ROS)的产生和扰乱内质网腔内的蛋白质折叠,有助于异常的蛋白质生成,内质网中异常折叠蛋白生成增多,超过其阈值并发生聚集、滞留,最终诱导内质网过度应激。内质网过度应激可通过PKC或FAM134B途径介导细胞自噬,自噬通过自我降解异常细胞器或错误折叠蛋白,以更新并维持细胞内环境稳态。关于自噬在骨骼肌损伤修复中的作用机制,除了内质网过度应激诱导,有关报道认为钝挫伤诱发的局部组织供氧不足,促使大量的ROS产生或AMPK信号通路的激活,均可诱导线粒体自噬而维持线粒体的稳定,减少能量消耗,从而有利于促进钝挫伤修复。虽然骨骼肌钝挫伤的损伤修复的机制错综复杂,但上述学说之间有交叉之处,因此对于骨骼肌钝挫伤的损伤修复机制研究可以围绕以上学说进一步深入研究,以明确不同学说在骨骼肌损伤修复的不同阶段如何发挥协同作用。     

The unfolded protein response modulates the autophagy‐mediated egg production in the mosquito Aedes aegypti

Mosquitoes must feed on vertebrate blood for egg development. As a consequence, some mosquito species are vectors for pathogens that cause devastating diseases in humans. Hence, understanding the mechanisms that control egg developmental cycles is important for developing novel approaches for the control of mosquito‐borne diseases. The unfolded protein response (UPR) is a cellular stress response related to endoplasmic reticulum (ER) stress. The UPR is activated in response to an accumulation of unfolded or misfolded proteins in the ER. Massive proteins have been shown to be produced during egg development, and it is obvious that unfolded or misfolded proteins may arise during vitellogenesis. It has been shown that autophagy in the mosquito fat body plays a central role in the progression of gonadotrophic cycles in the mosquito Aedes aegypti. However, the molecular mechanisms underlying the induction of UPR and the correlation between UPR and autophagy remain unclear. Here, we demonstrate that autophagy is activated during vitellogenesis and that the activation of autophagy is correlated with the UPR. We also show that the expressions of UPR and autophagy can be induced in an in vitro fat body culture system through an amino acid treatment. In addition, the expressions of UPR, autophagy‐specific markers and vitellogenin were also induced during dithiothreitol treatment. Interestingly, the silencing of UPR‐related genes significantly reduced the expression of autophagy‐specific markers and inhibited mosquito fecundity. Taken together, we conclude that autophagy‐mediated egg production in the mosquito A. aegypti is regulated by UPR.     

Cellular abnormalities linked to endoplasmic reticulum dysfunction in cerebrovascular disease--therapeutic potential

Unfolded proteins accumulate in the lumen of the endoplasmic reticulum (ER) as part of the cellular response to cerebral hypoxia/ischemia and also to the overexpression of the mutant genes responsible for familial forms of degenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyothrophic lateral sclerosis, and Huntington's disease, as well as other disorders that are caused by an expanded CAG repeat. This accumulation arises from an imbalance between the load of proteins that need to be folded and processed in the ER lumen and the ER folding/processing capacity. To withstand such potentially lethal conditions, stress responses are activated that includes the shutdown of translation to reduce the ER work load and the activation of the expression of genes coding for proteins involved in the folding and processing reactions, to increase folding/processing capacity. In transient cerebral ischemia, ER stress-induced suppression of protein synthesis is believed to be too severe to permit sufficient activation of the genetic arm of the ER stress response. Mutations associated with Alzheimer's disease down-regulate the ER stress response and make cells more vulnerable to conditions associated with ER stress. When the functioning of the ER is severely impaired and affected cells can no longer withstand these stressful conditions, programmed cell death is induced, including a mitochondria-driven apoptotic pathway. Raising the resistance of cells to conditions that interfere with ER functions and activating the degradation and refolding of unfolded proteins accumulated in the ER lumen are possible strategies for blocking the pathological process leading to cell death at an early stage.     

Sigma-1 receptors (sigma(1) binding sites) form raft-like microdomains and target lipid droplets on the endoplasmic reticulum: roles in endoplasmic reticulum lipid compartmentalization and export

The brain sigma-1 receptors can bind neurosteroids and psychotropic drugs, including neuroleptics and cocaine and are implicated in schizophrenia, depression, and drug dependence. In this study, we found that sigma-1 receptors specifically target lipid storage sites (lipid droplets) on the endoplasmic reticulum by forming a distinct class of lipid microdomains. Both endogenously expressing sigma-1 receptors and transfected C-terminally enhanced yellow fluorescent protein (EYFP)-tagged sigma-1 receptors (Sig-1R-EYFP) target unique "ring-like" structures associated with endoplasmic reticulum reticular networks in NG108-15 cells. The ring-like structures contain neutral lipids and are enlarged by the oleate treatment, indicating that they are endoplasmic reticulum-associated lipid droplets (ER-LDs). sigma-1 receptors colocalize with caveolin-2, a cholesterol-binding protein in lipid rafts on the ER-LDs, but not with adipocyte differentiation-related protein (ADRP), a cytosolic lipid droplet (c-LD)-specific protein. When the double-arginine ER retention signal on the N terminus of sigma-1 receptors is truncated, sigma-1 receptors no longer exist on ER-LDs, but predominantly target c-LDs, which contain ADRP. sigma-1 receptors on ER-LDs form detergent-resistant raft-like lipid microdomains, the buoyancy of which is different from that of plasma membrane lipid rafts. (+)-Pentazocine causes sigma-1 receptors to disappear from the microdomains. N-Terminally EYFP-tagged sigma-1 receptors (EYFP-Sig-1R) failed to target ER-LDs. EYFP-Sig-1R-transfected cells showed an unrestricted distribution of neutral lipids all over the endoplasmic reticulum network, decreases in c-LDs and cholesterol in plasma membranes, and the bulbous aggregation of endoplasmic reticulum. Thus, sigma-1 receptors are unique endoplasmic reticulum proteins that regulate the compartmentalization of lipids on the endoplasmic reticulum and their export from the endoplasmic reticulum to plasma membrane and c-LDs.     

Salidroside inhibits the proliferation and migration of gastric carcinoma cells and tumor growth via the activation of ERS-dependent autophagy and apoptosis

The endoplasmic reticulum stress (ERS)-induced autophagy and apoptosis are favorable for the suppression of many cancer types. Salidroside (Salid) has been proven to be capable of inducing the apoptosis of many cancer cells. However, the underlying mechanisms and whether Salid can activate the autophagic system have still not been explained thoroughly. Herein, the inhibition effect of Salid on the growth and progress of gastric cancer and the underlying mechanisms were investigated. With the SGC-7901 cells acting as the cancer model cells, we ascertained that Salid exerted a superior antagonism effect on the growth and migration of gastric cancer cells in a dose-dependent manner. Additionally, Salid exhibited strong capacity to induce cell apoptosis by the down-regulation of proliferation-related genes (Ki67 and PCNA), increase in the pro-apoptotic protein C-caspase-3, and changing the levels of other related genes. A mechanism study revealed that the levels of the ERS-related genes, such as CHOP, C-caspase-12, GADD34, and BiP, in the SGC-7901 cells dramatically changed post-treatment by Salid, indicating the involvement of ERS in Salid-inducing cell apoptosis. In addition, the increased LC3⁺ autophagic vacuoles, enhanced conversion of LC3-I to LC3-II, and inhibition of the PI3K/Akt/mTOR pathway further confirmed the activation of autophagy induced by Salid. Importantly, the effect of Salid in regulating the levels of autophagy-related proteins or the signaling pathway could be markedly depressed by co-incubating with Wortmannin (Wort), an autophagy inhibitor. The final evaluation of the tumor therapy efficacy exhibited satisfactory cancer growth inhibition by Salid with negligible toxicity to normal tissues. In summary, the present work provides a comprehensive effective evaluation of Salid for treating gastric cancer. The detailed investigation of the underlying mechanisms may offer a rational reference for the future applications of Salid in clinic.

The endoplasmic reticulum stress (ERS)-induced autophagy and apoptosis are favorable for the suppression of many cancer types.     

骨髓间充质干细胞及细胞因子在股骨头坏死治疗中的应用与展望

背景：单纯应用骨髓间充质干细胞治疗股骨头坏死的效果较差,若同时加入相关细胞因子可更好的发挥作用。目的：综述相关细胞因子诱导间充质干细胞在股骨头坏死治疗方面的应用。方法：由第一作者检索1989/2009PubMed数据库及万方数据库有关治疗股骨头坏死的新进展、骨髓间充质干细胞治疗骨科相关疾病、可促进间充质干细胞向成骨细胞分化的相关细胞因子及其作用机制等文献报道。结果与结论：骨形态发生蛋白、成骨生长肽、血管内皮生长因子、软骨源性形态发生蛋白1、生长转化因子β、胰岛素样生长因子1、血小板衍生生长因子等细胞因子被证实可诱导骨髓间充质干细胞分化为成骨细胞、软骨细胞,促进骨痂的愈合。因此临床中将骨髓间充质干细胞与细胞因子诱导技术相结合治疗股骨头坏死可最大程度优化治疗效果。     

C/EBP同源蛋白功能研究进展

C/EBP(CCAAT enhancer binding protein)同源蛋白(CHOP)通过显性负调控的方式抑制转录因子C/EBP和肝富集转录激活蛋白(LAP).CHOP是内质网应激介导的细胞凋亡通路中重要的中间信号分子.本文综述了CHOP蛋白的分子特征;CHOP在细胞凋亡,自噬和焦亡中参与的信号通路及调控作用;...     

Involvement of endoplasmic reticulum stress in myocardial apoptosis of streptozocin-induced diabetic rats

Apoptosis plays critical role in diabetic cardiomyopathy and endoplasmic reticulum stress (ERS) is one of intrinsic apoptosis pathways. For previous studies have shown that endoplasmic reticulum become swell in diabetic myocardium and ERS was involved in diabetes mellitus and heart failure, this study aimed to demonstrate whether ERS was induced in myocardium of streptozocin (STZ)-induced diabetic rats. We established type 1 diabetic rat model with STZ intraperitoneal injection, used echocardiographic evaluation, hematoxylin-eosin staining and the terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling staining to identify the existence of diabetic cardiomyopathy and enhanced apoptosis in the diabetic heart. We performed immunohistochemistry, Western blot and real time PCR to analysis two hallmarks of ERS, glucose regulated protein78 (Grp78) and Caspase12. We found both Grp78 and Caspase12 had enhanced expression in protein and mRNA levels in diabetic myocardium than normal rat's, and Caspase12 was activated in diabetic heart. Those results suggested that ERS was induced in STZ-induced diabetic rats' myocardium, and ERS-associated apoptosis took part in the pathophysiology of diabetic cardiomyopathy.