葡萄糖调节蛋白94在人胚胎发育中的表达

目的 为探讨葡萄糖调节蛋白９４（ＧＲＰ９４）在胚胎发育中的作用,研究了１０－３１周人胎组织ＧＲＰ９４的定位及表达。方法 用ＳＰ免疫组织化学方法。结果 结肠粘膜上皮,肾小管上皮及肝细胞的胞质内,在１０周已有ＧＲＰ９４的表达,１８－２０周时表达增多,一直维持较高水平。胃粘膜上皮及心肌细胞也有较强的表达。     

苯丙胺致大鼠黑质多巴胺神经元损伤与LaminB1和GRP94的关系

目的探讨苯丙胺对黑质DA神经元损伤的机制。方法将60只大鼠随机分为3组：空白组10只、生理盐水组10只、苯丙胺处理组40只。苯丙胺处理组又随机分为苯丙胺给药（剂量为2．5mg·kg-1·d-1）后1h、1d、7d和14d组,每组各10只。观察给药后的行为学变化,再用Westernblot方法检测各组黑质LaminB1和GRP94蛋白的表达量。结果苯丙胺在首次给药后就可引起大鼠自主活动量的增加。并且随着给药时间的延长出现了刻板行为：Westernblot方法检测黑质GRP94和LaminB1蛋白的表达在各组间未见差异。结论低剂量短时间苯丙胺对黑质DA能神经元的损害可能与GRP94和LaminB1蛋白的变化没有关系。     

一些与热休克蛋白有关的生物功能

热休克蛋白为一种应激蛋白，具有维持机体自身稳定的生物学功能，与衰老关系的研究正引起人们的关注。对热休克蛋白的特性、基因结构及与衰老的关系作一概述     

细胞外热休克蛋白70及其生物学功能

热休克蛋白(HSP)一直被描述为一种细胞内蛋白质在胞内发挥一系列生物学作用,参与细胞内蛋白质的折叠、装配、降解和修复过程。近年来,有研究发现HSP70能被主动释放到胞外,成为细胞外HSP70(extracellular HSP70,eHSP70),但关于其功能尚不清楚。循环HSP70水平与多种疾病进程密切相关。有研究发现暴露于物理和心理刺激源作用下,HSP70可能通过脂筏或Exosome介导的分泌途径释放到细胞外,作为一种生物活性因子影响多种疾病的进程。     

热休克蛋白在肿瘤免疫方面的研究进展

热休克蛋白(HSP)是细胞在应激条件下产生的一类高度保守的蛋白质,已被证实是一个强有力的免疫佐剂,在肿瘤免疫中充当了多重角色,对研制临床上有实用价值的肿瘤疫苗有重要的意义.此文综述了热休克蛋白及其在肿瘤免疫中的作用机制和在临床肿瘤疫苗研发中的应用前景.     

GRP78的研究进展

葡萄糖调节蛋白78是热休克蛋白70家族的成员之一,作为一种分子伴侣在蛋白质的折叠和转运过程及内质网应激反应中发挥重要作用。它在多种肿瘤组织中呈高表达,反义抑制其表达水平或将GRP78启动子连接自杀基因可用于肿瘤治疗。它在染铅的鼠C6细胞中也呈高表达,为神经系统防御机制的研究提供了一条新思路。     

bFGF对局灶性脑缺血大鼠脑组织GRP78表达的影响

目的研究大鼠脑缺血再灌注后对葡萄糖调节蛋白78(glucose-regulated protein78,GRP78)表达的影响,探讨碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)对脑组织缺血再灌注神经元GRP78的调节作用及机制。方法应用线栓法制作大鼠局灶性脑缺血再灌注模型,大脑中动脉阻塞2h再灌注损伤12h,采用TUNEL法、免疫组化检测海马及皮质内神经元凋亡和GRP78的表达。结果 sham组,海马及皮质偶见凋亡细胞,皮质及海马神经元内少见GRP78免疫反应阳性细胞;I/R组,海马及皮质神经元凋亡增加,缺血再灌注损伤后皮质及海马神经元内GRP78阳性表达明显高于假手术组。bFGF组,海马及皮质神经元凋亡减少,皮质及海马神经元内GRP78表达较I/R组明显增加。结论 bFGF显著减少缺血神经元凋亡,上调脑缺血诱导的GRP78表达,对脑缺血再灌注海马及皮质神经元的具有保护作用。     

SREBP-1C、GRP-94在小鼠肝细胞脂质代谢中的作用

目的探讨高同型半胱氨酸(Hcy)血症中肝细胞固醇调节元件结合蛋白(SREBP-1C)与葡萄糖调节蛋白94(GRP-94)的表达变化,评价内质网应激蛋白对肝细胞脂质代谢的影响。方法高蛋氨酸饮食诱导小鼠高Hcy血症,分析肝细胞内甘油三酯(TGE)、胆固醇(CHO)含量的变化,RT-PCR、Western blot分别检测内质网应激蛋白SREBP-1C和GRP-94mRNA及其蛋白表达。结果高蛋氨酸饮食后小鼠各时点血浆Hcy及肝细胞内TGE、CHO含量均显著升高,而血浆TGE、CHO含量升高并不明显;小鼠肝细胞内质网应激蛋白SREBP-1C和GRP-94mRNA及其蛋白表达也显著升高(P<0·05)。结论Hcy诱导的内质网应激可引起SREBP-1C、GRP-94的表达变化及内源性固醇调节通路失调。     

多肽P7对肿瘤组织的靶向识别与Hsp90表达水平相关

目的 分析热休克蛋白90(Hsp90)双功能靶向抑制多肽LPLTPLP(P7)对不同肿瘤组织及癌旁组织的识别效果,以及与Hsp90表达的相关性.方法 通过免疫组化和免疫荧光染色法分别检测组织芯片中48例16种器官肿瘤及匹配或不匹配的边缘或癌旁组织的Hsp90表达水平以及FITC-P7的识别效果,并对两组数据进行相关性分...     

Human Neurotropic JC Virus and Its Association with Brain Tumors

JC virus (JCV) is a human polyomavirus known as the causative agent of the fatal demyelinating disease, Progressive Multifocal Leukoencephalopathy (PML). Further, in experimental animals this virus causes a broad range of tumors of central nervous system origin. Recent studies have suggested the association of JCV with several human tumors most notably malignant brain tumors of childhood, medulloblastoma. The development of tumors by JCV is most likely through mechanisms involving inactivation of tumor suppressors and de-regulation of signaling pathways such as Wnt by the viral early protein, T-antigen. The neurotropic nature of JCV along with the overwhelming evidence for its oncogenic potential in laboratory animals and its detection in significant numbers of human medulloblastomas invite the re-evaluation of the role for JCV in the development of human brain tumors.     

Overexpression of GRP78 and GRP94 are markers for aggressive behavior and poor prognosis in gastric carcinomas

Glucose-related proteins (GRPs) are ubiquitously expressed in endoplasmic reticulum and able to assist in protein folding and assembly; consequently, they are considered as molecular chaperones. GRP78 and GRP94 expression was induced by glucose starvation and up-regulated in the malignancies. To clarify the roles of both molecules in tumorigenesis and progression of gastric carcinomas, immunohistochemistry was used on tissue microarray containing gastric carcinomas, adenomas, and nonneoplastic mucosa using the antibodies against GRP78 and GRP94, with a comparison of their expression with clinicopathological parameters of carcinomas. Gastric carcinoma cell lines (MKN28, AGS, MKN45, KATO-III, and HGC-27) were studied for both proteins by immunohistochemistry and Western blot. There was more expression of both proteins in gastric carcinoma and adenoma than in nonneoplastic mucosas (P < .05). All gastric carcinoma cell lines showed their expression at different levels. They were positively correlated with tumor size, depth of invasion, lymphatic and venous invasion, lymph node metastasis, and Union Internationale Contre le Cancer staging (P < .05), with positive relationship between both proteins (P < .05). Univariate analysis indicated the postsurgical cumulative survival rate of patients with positive GRP78 or GRP94 expression to be lower than that in those without GRP78 or GRP94 expression (P < .05), but the close link disappeared if stratified according to depth of invasion (P > .05). Multivariate analysis showed that age, depth of invasion, lymphatic invasion, lymph node metastasis, Union Internationale Contre le Cancer staging, and Lauren classification (P < .05), but not GRP78 and GRP94 expression, were independent prognostic factors for carcinomas (P > .05). Up-regulated expression of GRP78 and GRP94 was possibly involved in pathogenesis, growth, invasion, and metastasis of gastric carcinomas. They were considered objective and effective markers for the aggressive behavior and poor prognosis in gastric carcinomas.     

Inhibition of ICMT induces endothelial cell apoptosis through GRP94

Isoprenylcysteine-O-carboxyl methyltransferase (ICMT) catalyzes methylation of proteins containing a C-terminal CAAX motif. We have previously shown that chemical inhibition of ICMT caused endothelial cell apoptosis, an effect correlated with decreased Ras and RhoA carboxyl methylation and GTPase activities. In the current study, proteomic analysis of pulmonary artery endothelial cells (PAEC) exposed to the ICMT inhibitor, N-acetyl-geranylgeranyl-cysteine (AGGC), demonstrated a shift in the isoelectric points (pI) of the glucose-regulated protein (GRP) 94. Two-dimensional PAGE and immunoblot analysis further documented that ICMT inhibition caused multiple changes in the pI of GRP94. GRP94 is an endoplasmic reticulum molecular chaperone, a component of the unfolded protein response (UPR), and is involved in apoptosis. Immunofluorescence analyses revealed redistribution and aggregation of GRP94 after 3 h exposure to AGGC. A similar finding was noted with calnexin. In addition, GRP94 protein levels were significantly diminished upon 18 h AGGC exposure or ICMT suppression. The effects of ICMT inhibition on changes in GRP94 subcellular localization and protein content were blunted by overexpression of constitutively active RhoA or a caspase inhibitor. Furthermore, GRP94 depletion augmented endothelial cell apoptosis induced by ICMT inhibition. These results indicate that ICMT inhibition leads to GRP94 relocalization, aggregation, and degradation; effects were dependent upon the activities of RhoA and caspases. We speculate that changes in the pI, subcellular localization, and protein level of GRP94 cause endothelial cell apoptosis, possibly through UPR dysfunction. These studies suggest a novel link between RhoA GTPases and the UPR.     

Proliferative Activity in Pancreatic Endocrine Tumors: Association with Function,Metastases, and Survival

Endocrine tumors of the pancreas are slow-growing lesions, yet one-third to one-half will metastasize. It is generally accepted that histopathologic features do not reliably predict metastatic potential or outcome. We investigated whether proliferative activity, as determined by MIB-1 labeling, correlated with tumor type, metastasis, or patient survival. Formalin-fixed sections of pancreatic endocrine tumors were immunohistochemically stained for the MIB-1 antibody against Ki-67 using the avidin-biotin complex technique. Labeling index (LI) was determined by counting 1000 consecutive tumor cells in an area of greatest staining intensity at ×400 and expressed as a percentage. The study group included 37 patients, including 10 gastrinomas, 9 insulinomas, 4 glucagonomas, 2 VIPomas, and 12 nonfunctioning tumors. Twenty-one patients had metastases, primarily to regional lymph nodes and the liver. Five patients had MEN I. MIB-1 LI was significantly greater in the nonfunctioning tumors (mean 20.9%) than in the functioning tumors (mean 5.1%) (p = 0.01). LI for functional tumors (insulinomas 6.4%, glucagonoma 4.4%, gastrinomas 3.2%, VIPomas 3.2%) were similar to each other. MIB-1 was significantly higher in those tumors that metastasized (mean 15.6%) compared to those that did not (mean 3.1%), (p = 0.04). All tumors with MIB-1 LI≥10% developed metastases. Logistic regression showed that MIB-1 was a significant predictor of metastases (p = 0.003) after adjusting for functional status. MIB-1 LI also correlated with outcome in that those patients with MIB-1 LI ≥10% had a mean survival of 19 mo compared to 72 mo for those with levels <10% (p = 0.0001). Results of the proportional hazards model showed that MIB-1 remained a significant (p = 0.03) and independent predictor of survival times after adjustment for tumor size and functional status. Higher MIB-1 LI values, were significantly associated with shorter survival times. In conclusion, MIB-1 LI appears to be a useful indicator of metastatic potential and is predictive of outcome in PET.     

Immunolocalization and heart levels of GRP94 in the mouse during post-implantation development

 Glucose-regulated proteins (GRPs), which belong to the highly conserved family of stress proteins, are resident to the endoplasmic reticulum and function as molecular chaperones. Heat shock proteins have been shown to be developmentally regulated, but little work has been done to investigate the expression of GRPs during embryogenesis. Therefore, this study examined the distribution of GRP94 within mouse embryos during the period of organogenesis and characterized levels of GRP94 within the developing heart during organogenesis and late fetal stages. Our results demonstrate that the GRP94 protein is constitutively expressed within mouse embryos during early stages of organogenesis and is localized particularly within the developing heart, neuroepithelium, and surface ectoderm tissues. Positive staining for GRP94 remains within developing heart tissues throughout organogenesis and is found primarily within the atrial and ventricular myocardial cells. Western blot analysis of GRP94 expression demonstrates a significantly higher level of GRP94 in embryonic hearts during early stages of organogenesis than in later stages of organogenesis or the fetal period. These results demonstrate that the stress protein GRP94 is constitutively expressed within specific tissues during post-implantation mouse development and suggest that GRPs may play an important role in the process of myocardial cell differentiation and heart development. Accepted: 9 June 1997     

子宫颈癌组织中GRP94的表达及意义

目的 探讨子宫颈鳞状细胞癌中GRP94蛋白的表达及其临床意义.方法 采用Western Blot和免疫组化法检测32例子宫颈鳞状细胞癌及30例正常子宫颈组织中GRP94蛋白的表达,分析GRP94表达情况与子宫颈癌之间的关系.结果 GRP94蛋白在子宫颈鳞状细胞癌中表达水平明显高于正常子宫颈组织(P<0.05),并呈现出向核周集中的趋势.结论 GRP94的高表达与子宫颈癌的发生、发展密切相关,有望成为评价肿瘤生物学行为的一个新的指标.     

GRIM-19的功能及与肿瘤的相关性

GRIM-19最初被认为定位于细胞核,后来发现在线粒体中也有表达。GRIM-19还是线粒体中NADH脱氢酶1复合物的基本亚单位,在线粒体Ⅰ型呼吸过程中至关重要。在病毒感染导致细胞癌变的过程中,GRIM-19很可能是病毒癌基因结合的靶点,目前认为,GRIM-19参与和细胞的增殖、凋亡的调控过程,其表达降低或位点突变可以导致细胞的异常增殖和恶性转化。在肿瘤的形成及凋亡抑制中发挥着重要的作用。