葡萄糖调节蛋白78促进肝硬化大鼠心肌细胞凋亡及其机制

 目的： 探讨葡萄糖调节蛋白78/免疫球蛋白重链结合蛋白(GRP78/BiP)是否促进肝硬化大鼠心肌细胞凋亡及其发生机制。方法： 采用复合致病因素法建立肝硬化大鼠模型,在4周、6周和8周分别取材。实验1：取心脏称重并测量左室壁厚度,计算左室壁厚度与心脏重量比值及心脏指数。实验2： TUNEL法观察心肌细胞凋亡情况;免疫组化方法检测心肌组织中GRP78/BiP蛋白以及凋亡相关蛋白CCAAT增强子结合蛋白同源蛋白/生长停滞及DNA诱导蛋白153（CHOP/GADD153）、半胱氨酸天冬氨酸蛋白酶12（caspase-12）、核转录因子κB p65（NF-κB p65）、B细胞淋巴瘤/白血病蛋白2（Bcl-2）的表达。结果： 随肝硬化病程进展,左室壁厚度与心脏重量比值以及心脏指数逐渐增加,8周组增加显著(P<0.05);心肌细胞凋亡指数、CHOP/GADD153和caspase-12阳性蛋白表达指数逐渐升高,8周组差异显著(P<0.05);NF-κB p65和Bcl-2阳性蛋白表达指数呈一致性变化,在4周组较其它组明显增高(P<0.05); GRP78/BiP蛋白阳性表达指数与心肌细胞凋亡指数、CHOP/GADD153、caspase-12蛋白阳性表达指数呈显著正相关,CHOP/GADD153与NF-κB p65、Bcl-2蛋白阳性表达指数呈显著负相关。结论： GRP78高表达在内质网应激介导的肝硬化心肌病发病中可能发挥重要作用。     

四氯化碳诱导性肝硬化大鼠肝组织葡萄糖调节蛋白78表达的研究

目的研究四氯化碳(CCl4)诱导性肝硬化大鼠肝组织内葡萄糖调节蛋白78(GRP78)表达的变化。方法将健康雄性Wistar大鼠随机分为对照组(n=5)和肝硬化组(n=5),对照组皮下注射植物油0.12ml/100g体重,肝硬化组以0.3ml/100g体重皮下注射60%CCl4植物油。在实验第21周的第1d杀死鼠,右心室取血检测肝功能指标。鼠肝中叶取材,石蜡切片行苏木精-伊红(HE)染色和天狼猩红组织化学染色,光镜观察形态学改变,行GRP78免疫组织化学显色,无菌下取肝组织行Western blotting及RT-PCR检测肝组织GRP78的表达。结果肝硬化组的血清ALT含量(278.2±88.42)明显高于对照组(154.8±9.94,t=3.10,P<0.05);ALB含量(1.68±0.62)明显低于对照组(3.02±1.96,t=2.62,P<0.05)。对照组肝小叶结构和肝细胞状态正常,仅在中央静脉及汇管区可见少量胶原纤维。20周肝硬化组的肝细胞脂肪变性明显,胶原纤维大量增生,假小叶形成。GRP78免疫组织化学呈色显示,肝硬化组肝组织中阳性细胞数明显多于对照组,棕黄色着色定位于细胞质中。Western blotting和RT-PCR显示肝硬化组肝组织GRP78的表达明显增强。结论在CCl4诱导性肝硬化的肝组织中,GRP78表达明显增强,这可能与肝细胞的内质网应激有关。     

葡萄糖调节蛋白78在宫颈癌细胞衰老过程中的表达研究

目的探讨葡萄糖调节蛋白78（glucose regulated protein,GRP78）在顺铂诱导宫颈癌细胞衰老过程中的表达变化情况及相关机制。方法亚凋亡剂量顺铂诱导宫颈癌细胞衰老;β-半乳糖苷酶染色检测细胞衰老情况;P1染色流式细胞仪检测细胞周期变化;Western blot检测GRP78蛋白表达情况;siRNA反义抑制GRP78表达,western blot检测DNA损伤修复基因ATM（ataxia—telangiectasia mutated）通路相关基因表达情况。结果亚凋亡计量顺铂能够成功诱导宫颈癌细胞衰老,细胞主要阻滞于G2／M期。Western blot检测表明在宫颈癌细胞衰老过程中GRP78蛋白表达明显降低。反义抑制GRP78蛋白表达后ATM通路相关蛋白P53及p-Cdc2表达明显升高,而Cdc2蛋白表达明显降低。结论GRP78蛋白在顺铂诱导宫颈癌细胞衰老过程中起抵抗作用,主要可能通过影响ATM通路相关基因的表达发挥作用。     

葡萄糖调节蛋白78在复合致病因素诱导的大鼠肝肺综合征中的作用

目的:探讨葡萄糖调节蛋白78(GRP78)在大鼠肝肺综合征发病中的作用及其与肠源性内毒素血症的关系。方法:Wistar大鼠被随机分为4周组、6周组和8周组3个时点,采用复合致病因素法制备大鼠肝硬化合并肝肺综合征(HPS)模型,并设标准饮食的正常大鼠作为对照组。采用HE染色观察肺组织病理变化;测定血浆中丙氨酸氨基转移酶(ALT)、内毒素、TNF-α和肺组织匀浆中的TNF-α、丙二醛(MDA)的含量。Westernblotting和RT-PCR法检测肺组织标本中GRP78蛋白和mRNA表达水平。结果:模型组动物血浆内毒素含量随病程进展逐渐增高;肺组织中GRP78蛋白和mRNA的表达随HPS进展逐步增高,且各时点间的表达有显著差异(P<0.05);血浆内毒素与升高的GRP78蛋白水平间呈高度正相关(P<0.01)。血浆ALT和TNF-α含量以及肺组织匀浆中TNF-α和MDA含量随病程进展逐渐增高;血浆内毒素含量以及肺组织中GRP78蛋白分别与血浆TNF-α和肺组织中TNF-α、MDA的含量呈高度正相关(P<0.01)。在各时点,模型组动物血浆TNF-α含量、肺组织匀浆TNF-α、GRP78蛋白及mRNA均显著高于正常对照组(P<0.05)。在第6周和第8周,模型组动物血浆内毒素和ALT的含量以及肺组织匀浆中MDA的含量均显著高于正常对照组(P<0.05)。结论:肝硬化时形成的肠源性内毒素血症作为内质网应激的重要应激原,通过氧化应激激活肺组织的内质网应激反应导致GRP78表达增高,很可能是HPS发病的重要机制。     

糖调节蛋白78在大鼠肠源性内毒素血症促进肝硬化形成中的作用

目的:探讨糖调节蛋白78(GRP78)在大鼠肠源性内毒素血症(IETM)促进肝硬化形成过程中的作用。方法:51只雄性Wistar大鼠随机分为肝硬化模型4周组、6周组、8周组及同期正常对照组。采用复合致病因素法诱导大鼠肝硬化,HE染色和VG染色分别观察肝损伤和肝纤维化情况;RT-PCR法和免疫组化法分别检测肝组织GRP78mRNA及蛋白表达;同时测定血浆中丙氨酸氨基转移酶(ALT)、内毒素、肿瘤坏死因子-α(TNF-α)、同型半胱氨酸(HCY)以及肝组织匀浆中TNF-α、丙二醛(MDA)、Ⅲ型前胶原(PⅢP)水平。结果:(1)随病程进展,各模型组血浆中ALT、内毒素、TNF-α、HCY以及肝组织中GRP78mRNA、蛋白表达水平、MDA、TNF-α、PⅢP含量和肝组织纤维化指数均逐渐升高并显著高于正常对照组(P<0.05)。(2)血浆中升高的内毒素水平分别与GRP78蛋白、血浆MDA和HCY水平以及肝纤维化指数呈显著正相关(P<0.01);表达增高的GRP78蛋白分别与血浆MDA和HCY水平以及肝纤维化指数呈显著正相关(P<0.01)。结论:GRP78可能在肝硬化形成过程中发挥重要作用;内质网应激很可能是IETM促进肝纤维化乃至肝硬化发生的重要机制。     

肝纤维化大鼠肝细胞内质网形态及GRP78表达的研究

目的:观察四氯化碳(CCl4)致大鼠肝纤维化过程中内质网形态及内质网应激标志性蛋白——葡萄糖调节蛋白78(GRP78)的表达变化,探讨内质网应激在肝纤维化发病机制中可能的作用。方法:雄性Wistar大鼠皮下注射CCl4制备肝纤维化模型,分别在4周及8周处死大鼠测定肝脏指数、血清丙氨酸氨基转移酶(ALT)和天冬氨酸氨基转移酶(AST)活性,观察肝组织病理改变和肝细胞内质网形态,免疫组化和real-timePCR分别检测肝组织GRP78蛋白及mRNA表达变化。结果:肝纤维化组大鼠肝脏指数、血清ALT和AST活性显著高于正常对照组(P<0.01),肝纤维化明显,电镜下见肝细胞内质网扩张,数量明显减少;肝细胞胞浆中GRP78蛋白表达量及mRNA表达量较正常组显著增加(P<0.01)。结论:在CCl4诱导的肝纤维化发生过程中肝细胞内质网形态有明显损伤性变化,内质网应激蛋白GRP78蛋白及基因表达水平明显增加,提示内质网应激参与肝纤维化发生发展。     

葡萄糖调节蛋白在肿瘤的表达和治疗中的作用

葡萄糖调节蛋白78 (glucose-regulated protein 78,GRP78)是内质网应激(endoplasmic reticulum stress)相关的重要分子伴侣,涉及到多种肿瘤的增殖、存活、转移等演化过程.作为一种应激蛋白,GRP78在机体正常组织中几乎不表达,而在处于缺氧应激状态下的肿瘤组织中高...     

葡萄糖调节蛋白78在大鼠肝肺综合征肺微血管重构中的作用

目的：探讨葡萄糖调节蛋白78(GRP78)引发大鼠肝肺综合征（HPS）肺微血管重构的机制。方法：Wistar大鼠被随机分为4周组、6周组和8周组3个时点,采用复合致病因素法制备大鼠肝硬化合并HPS模型,并设标准饮食的正常大鼠作为对照组。免疫组化染色法观察肺组织GRP78、Ⅷ因子相关抗原(FⅧ-RAg)C/EBP同源蛋白(CHOP)/生长阻滞及DNA损伤诱导蛋白153(GADD153)、caspase-12、Bcl-2和核因子(nuclearfactor,NF)-κB的表达。RT-PCR和Westernblotting法检测肺组织血管内皮生长因子(VEGF)mRNA和蛋白表达水平。结果：模型组动物肺组织中GRP78、FⅧ-RAg及VEGF蛋白的表达随HPS进展逐步增高,CHOP/GADD153及caspase-12的表达随HPS进展逐步降低,Bcl-2和NF-κB随病程进展表达逐渐增加,NF-κB尤以胞核表达增高明显。GRP78与FⅧ-RAg及VEGF蛋白水平呈明显正相关(P<0.01),而与CHOP/GADD153及caspase-12的表达呈明显负相关(P<0.01)。在各时点,模型组动物肺组织GRP78和FⅧ-RAg显著高于正常对照组;VEGF蛋白和mRNA均显著高于正常对照组;而CHOP/GADD153及caspase-12的表达均低于正常对照组(P<0.05)。结论：GRP78可能通过促进血管内皮细胞增殖和抑制其凋亡,促进肺微血管重构,导致HPS的发病。     

内质网应激相关分子葡萄糖调节蛋白78及增强子结合蛋白同源蛋白在高血压大鼠全脑缺血海马区的表达变化

目的:观察血压正常大鼠和高血压大鼠全脑缺血再灌注后海马区CAAT/增强子结合蛋白同源蛋白(CHOP)、葡萄糖调节蛋白78(GRP78)的表达变化,探讨内质网应激在高血压增加脑缺血再灌注神经易损性中的作用.方法:60只雄性血压正常Wistar-Kyoto(WKY)大鼠随机分为假手术组(Sham)和全脑缺血再灌注组(I/R);另取30只雄性自发性高血压大鼠为高血压全脑缺血再灌注组(SHR+I/R).应用改良的Pulsineli 4血管阻断(4-VO)法制作全脑缺血再灌注模型.各组分别在术后6、24、48 h,H-E染色观察海马区神经细胞形态变化;免疫组织化学和免疫印迹检测海马区CHOP、GRP78的表达;48 h八臂迷宫检测动物行为学变化.结果:与Sham组比较,I/R组各时间点存活神经元数量降低;GRP78表达增高,24 h达高峰;CHOP表达增高,24 h达高峰,高表达持续至48 h;与I/R组比较,SHR+ IR组各时间点存活神经细胞数量降低;GPR78表达6h增高,24、48h显著减少;6、24 h CHOP表达增高,48 h明显减少;八臂迷宫结果显示SHR+I/R组与I/R组比较,各检测指标变化差异有统计学意义.结论:高血压可增加脑缺血再灌注神经易损性,与加重缺血再灌注后GRP78表达下降、CHOP活体表达增高有关.     

单侧输尿管梗阻的大鼠内质网应激相关蛋白表达上调

目的探究内质网应激(ERS)相关凋亡通路在单侧输尿管梗阻(UUO)大鼠肾间质纤维化中的作用机制。方法将大鼠随机分为假手术组及UUO模型组,UUO组行左侧输尿管结扎术,于术后3、7和14 d HE和Masson染色观察肾脏病理变化;眼底静脉丛取血,分离血清测定血尿素氮及肌酐;Western blot检测葡萄糖调节蛋白78(GRP78)、内质网源性转录因子(CHOP)、凋亡相关蛋白半胱氨酸天门冬氨酸蛋白酶3(caspase-3)及caspase-12蛋白表达。结果与假手术组相比,UUO模型组可见:1)肾小管扩张和肾间质纤维化程度随输尿管梗阻时间延长而渐进性加重;2)GRP78、CHOP、caspase-3及caspase-12蛋白表达在术后3 d均有上调,随着梗阻时间延长,上述蛋白表达更显著(P0.01)。结论内质网应激相关标志性蛋白在UUO大鼠肾间质纤维化的早期即存在表达上调,可能促进了肾间质纤维化不断进展。     

Expression of glucose-regulated stress protein GRP78 is related to progression of melanoma

Aims:  Glucose-regulated protein 78 (GRP78) is a protein translated in response to endoplasmic reticulum (ER) stress that has been implicated in the pathogenesis and resistance to therapy of a variety of cancers. The aim of this study was to investigate its expression and role in the development and progression of human melanoma.
Methods and results:  The immunohistochemical expression of GRP78 in naevi, primary melanoma and melanoma metastases from 171 patients was correlated with clinicopathological factors and patient survival. The GRP78 immunoreactivity score (IRS) was 0.2 in compound naevi, 0.65 in dysplastic naevi, 4.65 in naevi adjacent to primary melanoma, 2.4 in melanoma in situ , 11.2 in thin (≤1.0 mm) and 18.1 in thick (>1.0 mm) primary melanoma. It was 18 and 17.3 in subcutaneous and lymph node metastases, respectively ( P  < 0.0001). GRP78 expression was positively correlated with increasing tumour thickness ( P  = 0.001) and with increasing dermal tumour mitotic index ( P  = 0.0004). Disease-free survival (χ² = 8.0703, P  = 0.0045) and overall survival (χ² = 6.2633, P  = 0.0123) in melanoma patients with IRS >25 were significantly lower than in melanoma patients with IRS <25.
Conclusions:  GRP78 expression appears to correlate with known correlates of melanoma progression and survival and requires further evaluation as a prognostic biomarker in melanoma.     

Increased expression of 78 kD glucose-regulated protein promotes cardiomyocyte apoptosis in a rat model of liver cirrhosis

Aims: This study was to investigate the role and underlying mechanism of 78 kD glucose-regulated protein (GRP78) in cardiomyocyte apoptosis in a rat model of liver cirrhosis. Methods: A rat model of liver cirrhosis was established with multiple pathogenic factors. A total of 42 male SD rats were randomly divided into the liver cirrhosis group and control group. Cardiac structure analysis was performed to assess alterations in cardiac structure. Cardiomyocytes apoptosis was detected by TdT-mediated dUTP nick end labeling method. Expression of GRP78, CCAAT/enhancer-binding protein homologous protein (CHOP), caspase-12, nuclear factor kappa-light-chain-enhancer of activated B cells p65 subunit (NF-κB p65) and B cell lymphoma-2 (Bcl-2) was detected by immunohistochemical staining. Results: The ratios of left ventricular wall thickness to heart weight and heart weight to body weight were significantly increased with the progression of liver cirrhosis (P < 0.05). Apoptosis index of cardiomyocytes was significantly increased with the progression of liver cirrhosis (P < 0.05). The expression levels of GRP78, CHOP and caspase-12 were significantly increased in the progression of liver cirrhosis (P < 0.05). The expression levels of NF-κB p65 and Bcl-2 were highest in the 4-wk liver cirrhosis, and they were decreased in the 6-wk and 8-wk in the progression of liver cirrhosis. GRP78 expression levels were positively correlated with apoptosis index, CHOP and caspase-12 expression levels (P < 0.05). CHOP expression levels were negatively correlated with NF-κB p65 and Bcl-2 expression levels (P < 0.05). Conclusion: Increased expression of GRP78 promotes cardiomyocyte apoptosis in rats with cirrhotic cardiomyopathy.     

人GRP78蛋白的原核表达、纯化及抗原活性鉴定

目的:构建原核表达质粒pGEX-4T-1 -GRP78,诱导表达、纯化后检测GRP78蛋白的抗原活性.方法:利用PCR方法从本实验室已构建的真核表达载体pcDNA3.1(+)上扩增GRP78基因,将其克隆至原核表达载体pGEX-4T-1,构建重组载体pGEX-4T-1 -GRP78.转化至大肠杆菌BL21( DE3)中诱导表达,再将所表达的融合蛋白进行纯化.经SDS-PAGE分析后,将所得产物用Thrombin切割;进一步包板后用ELISA法对其抗原活性进行评价.结果:酶切和测序结果均证实GRP78原核表达载体构建正确,可诱导表达;ELISA检测显示纯化后的人GRP78抗原具有免疫原性.结论:成功构建了人GRP78基因的原核表达载体,获得了纯化的GRP78蛋白,该蛋白具有良好的抗原活性,为进一步研究以GRP78为基础的肝细胞癌的血清学检测提供了抗原.     

Glucose regulated protein 78 (GRP78) is overexpressed in colorectal carcinoma and regulates colorectal carcinoma cell growth and apoptosis

Glucose regulated protein 78 (GRP78) plays an important role in the development and progression of cancer. However, the role of GRP78 in colorectal carcinoma still remains unclear. In this study, using immunohistochemistry and RT-PCR, we explored the expression patterns of GRP78 in colorectal carcinoma. We knocked down GRP78 expression in RKO cells using shRNA-GRP78. Apoptosis and proliferation assay were performed. We found increased GRP78 expression with progression along the normal tissue–adenoma–carcinoma sequence, while there was no difference in the relative mRNA expression of GRP78 among normal, adenoma and colorectal carcinoma. The shRNA-GRP78 plasmid caused a significant reduction of GRP78 expression at both mRNA and protein levels. Furthermore, knockdown of GRP78 not only efficiently suppressed proliferation of RKO cells, but also induced early apoptosis of cells. In conclusion, our study demonstrated that GRP78 may play some important roles in the development and progression of colorectal carcinomas. The expression of GRP78 is associated with the enhanced proliferation of colorectal carcinoma cells and with their resistance to apoptosis.     

内质网应激在肝脏相关疾病中的研究进展

内质网应激(ERS)是一种重要的细胞自我保护机制,能够激活未折叠蛋白反应(UPR),促进细胞的生存,但持续的ERS将导致细胞的凋亡。肝细胞内存在大量的内质网,许多肝脏相关疾病均与内质网应激有关,如酒精性肝病,非酒精性肝病,中毒性肝损伤,病毒性肝炎,肝恶性肿瘤及肝脏缺血再灌注损伤等。本文将从ERS在肝脏相关疾病发病机制中的作用以及在肝病干预治疗上的意义等方面进行综述。     

金属硫蛋白降低GRP78和CHOP蛋白表达减轻大鼠砷中毒肝细胞凋亡

目的 研究葡萄糖调节蛋白78(GRP78)、C/EBP环磷酸腺苷反应元件结合转录因子同源蛋白(CHOP)在金属硫蛋白(MT)减轻大鼠砷中毒肝细胞凋亡中的作用.方法 建立MT治疗亚砷酸钠(NaAsO2)诱导的大鼠砷中毒肝损伤模型,用MT治疗2周,以TUNEL法检测肝细胞凋亡,免疫组化法、Western blot检测大鼠肝脏GRP78、CHOP蛋白表达.结果 砷中毒模型组大鼠肝细胞凋亡、肝组织GRP78和CHOP蛋白表达较对照组显著升高(P＜0.05),MT治疗组肝细胞凋亡、肝组织GRP78和CHOP蛋白表达明显回降(P＜0.05),但仍然高于对照组(P＜0.05).结论 MT可通过降低GRP78和CHOP蛋白表达减轻大鼠砷中毒所致的肝细胞凋亡.     

Lipid droplet-associated proteins in alcoholic liver disease: a potential linkage with hepatocellular damage

Steatosis is a characteristic morphological change of alcoholic liver disease, but its pathologic significance is still obscure. Regardless of cell types, intracellular lipid droplets are coated with a phospholipid monolayer, on which many kinds of lipid droplet-associated proteins are present. These proteins, such as the perilipin family of proteins and the cell death inducing DNA fragmentation factor (DFF) 45-like effectors, are recognized to play important roles in lipid metabolism in the physiological settings. In addition, recent lipidology studies have revealed that expression of the lipid droplet-associated proteins possibly participate in the pathologic processes of many metabolic disorders, including fatty liver and insulin resistance. Hence, controlling protein expressions is expected to offer novel therapeutic options. In this review, we summarize collected data concerning the potential contribution of the lipid droplet-associated proteins to the development of alcoholic fatty liver. Without exception, existing data indicates that the lipid droplet-associated proteins, especially the perilipin family proteins, are important factors in alcoholic fatty liver. These proteins exert a prosteatotic effect, and their expression is closely associated with lipotoxicity based on endoplasmic reticulum stress and oxidative injury. Although suppression of their expression may be beneficial, careful consideration is required because these proteins simultaneously function as protective factors against lipotoxicity.     

内质网应激对微囊化HepG2细胞脂代谢影响及调控研究

研究内质网应激发生对微囊化细胞脂代谢调节的影响,探讨内质网应激拮抗剂对微囊化细胞生长代谢调控的可行性.采用静电液滴法制备微囊化细胞,Real-time PCR法检测微囊化对葡萄糖调节蛋白78(GRP78)和C/EBP同源蛋白(CHOP)表达影响;通过MTT法检测细胞活性,ELISA法检测白蛋白含量,乙烷-丙酮法抽提测定胞内总胆固醇和甘油三酯含量,并比较拮抗剂四苯基丁酸(4-PBA)干预后相关指标变化.结果显示,微囊细胞中内质网应激标识蛋白GRP78和CHOP表达量分别为同天数下平面细胞3.6倍和1.9倍(P＜0.05),胞内总胆固醇(CHO)和甘油三酯(TG)含量分别为平面细胞1.7倍和3.2倍(P＜0.05).内质网应激拮抗剂4-PBA在1.0 mM可显著增加微囊化细胞活性.干预后GRP78和CHOP基因表达水平降低50％和30％ (P ＜0.05),胞内CHO和TG含量降低30％和15％ (P ＜0.05),并使白蛋白水平较对照组显著提高(P＜0.05).结果提示微囊内存在内质网应激,且与微囊细胞脂代谢失调有关;内质网应激拮抗剂能缓解微囊对细胞的以上作用.     

Overexpression of GRP78 protects glial cells from endoplasmic reticulum stress

Endoplasmic reticulum (ER) stress induces apoptotic cell death by causing the accumulation of structurally abnormal proteins. The 78-kDa glucose-regulated protein (GRP78) is an ER chaperone that regulates protein folding in the ER and has been suggested to contribute to cell survival. Using the rat C6 glioma cell line and flow cytometry, we assessed GRP78 expression following tunicamycin- and glutamate-induced ER stress. The results showed that GRP78 expression is upregulated following ER stress and has protective effects on injured glial cells. Annexin V and propidium iodide labeling revealed cells transiently expressing GRP78 prior to injury were protected against high-concentrations of tunicamycin and glutamate within 72 h. Our findings support the hypothesis that GRP78 inhibits cell death associated with ER stress.