uPA/uPAR/PAI系统与炎性关节疾病

近年来研究表明,尿激酶型纤溶酶原激活剂(urokinase-type plasminogen activator,uPA)/尿激酶型纤溶酶原激活剂受体(uPA receptor,uPAR)/纤溶酶原激活剂抑制剂(plasminogen activator inhibitor,PM)系统与炎性关节疾病中滑膜增生以及关节软骨和骨的破坏密切相关,本文就近年来的研究进展作一综述,旨在为炎性关节疾病的防治寻找新的靶点和途径.     

纤溶酶原激活剂抑制物2型的结构与功能

纤溶酶原激活剂抑制物2型(PAI-2)具纤溶抑制活性,是尿激酶(uPA)特异的抑制物。u-PA在肿瘤浸润与转移过程中起了十分关键的作用,PAI-2亦因此成为当今研究的热点。本文对PAI-2的基因结构、表达调控、蛋白质结构、功能及其作用机制等进行了综述。     

uPA／uPAR研究进展

纤溶酶原激活剂 /纤溶酶原激活剂抑制剂 (PA/PAI)系统是一个蛋白水解酶激活剂 /激活剂抑制剂系统 ,包括 6种成员 ,即尿激酶型PA(uPA)、组织型PA(tPA)、1型PA抑制剂 (PAI 1)、2型PA抑制剂 (PAI 2 )、3型抑制剂 (PAI 3)及uPA受体 (uPAR) ,其中uPA/uPAR系统是其中较为重要的成分。uPA/uPAR参与细胞因子和其他因子的激活、黏着键的裂解、细胞外基质的破坏、生物活性介质的失活、细胞内蛋白的水解以及信号的转换等重要活动。它与体内纤溶、生殖、皮肤上皮分化生长和再生过程及肿瘤细胞的转移浸润密切相关。     

纤溶酶原激活剂抑制物2型抑制细胞凋亡的研究进展

纤溶酶原激活剂抑制物2型(PAI-2)是一种多功能蛋白质,除了能有效抑制尿激酶(uPA)和双链组织型纤溶酶原激活物(tPA)而调节纤溶活性外,还参与了很多其它的生理病理过程,例如组织重建、胚胎发育、感染、免疫系统发育、肿瘤浸润和迁移等。更有研究表明胞内型PAI-2在抑制细胞凋亡方面也发挥着重要作用。本文就近年来PAI-2抑制细胞凋亡的研究进展作一综述。     

体外培养的血管内皮细胞低氧低糖损伤后tPA、PAI-1表达变化

目的：观察体外培养的血管内皮细胞低氧低糖损伤后组织型纤溶酶原激活剂(tPA)、Ⅰ型纤溶酶原激活物抑制因子(PAI-1)表达变化，探讨脑缺血后纤溶系统的变化及机制。材料和方法：制备体外内皮细胞低氧低糖损伤模型，利用HE染色、免疫细胞化学染色观察tPA、PAI-1表达变化。结果：低氧低糖损伤后，tPA、PAI-1表达均明显增强。结论：成功制备体外内皮细胞低氧低糖损伤模型。内皮细胞低氧低糖损伤可以诱导tPA、PAI-1表达增多，进一步说明脑缺血损伤后tPA、PAI-1表达增加并参与损伤过程。     

慢性肾脏疾病血清和尿液纤溶活性物质的改变及临床意义

目的探讨慢性肾脏疾病血清和尿液纤溶活性物质的改变及其临床意义。方法选择38例慢性肾小球肾炎(CGN),28例肾病综合征(NS),36例非透析治疗的慢性肾功能不全(CRF)和20例正常对照作为研究对象,应用ELISA法检测血清和尿液中组织型纤溶酶原激活剂(t-PA)和纤溶酶原激活物抑制剂-1(PAI-1)的浓度,同时分析尿中t-PA和PAI-1的水平与血t-PA、PAI-1、血肌酐和24h尿蛋白总量之间相关性。结果慢性肾脏疾病出现血清t-PA、PAI-1升高,尿液t-PA、PAI-1降低,其中尿液t-PA、PAI-1的改变独立于血清,不受血肌酐和24h尿蛋白定量的影响。结论慢性肾脏疾病患者存在纤溶活性物质的异常,其中尿液纤溶活性物质的改变可反应肾脏内皮细胞损伤。     

围产期缺氧缺血性脑损伤时基膜与TPA变化的相关性

为了探讨缺氧缺血后基膜与脑组织纤溶酶原激活剂变化的相关性。本实验通过“延迟剖宫产术”致胎鼠宫内窘迫 ;实验分空白对照组、缺氧缺血 15 min组和缺氧缺血 3 0 min组。上述三组分别取额、顶叶 ,透射电镜下观察血脑屏障的变化 ,每组各取8例测试脑组织纤溶酶原激活剂的活性。结果显示 :缺氧缺血 15 min时部分星形胶质细胞足板肿胀、血管周隙扩张 ;缺氧缺血 3 0min,基膜样物质减少 ,神经元显著肿胀。缺氧缺血 15 min、3 0 min,组织纤溶酶原激活剂活性升高 ,并且随缺氧缺血时间的延长 ,组织纤溶酶原激活剂呈增高趋势 ,经 t检验 ,P<0 .0 1。以上结果表明 :缺氧缺血后脑组织纤溶酶原激活剂活性增高 ,引起毛细血管基膜降解 ,打开血脑屏障 ,导致脑水肿。组织纤溶酶原激活剂是脑缺氧缺血引起神经元不可逆损伤的一个重要媒介     

组织纤溶酶原激活剂及其抑制物的研究进展

纤溶酶原转变成有纤溶活性的纤溶酶是纤溶过程中决定性的一步。组织型纤溶酶原激活剂（ｔｉｓｓｕｅｔｙｐｅｐｌａｓｍｉｎｏｇｅｎａｃｔｉｖａｔｏｒ,ｔＰＡ）是体内主要的纤溶酶原激活物,而纤溶酶原激活剂抑制物（ｐｌａｓｍｉｎｏｇｅｎａｃｔｉｖａｔｏｒｉｎｈｉｂｉｔｏｒ,ＰＡＩ）是组织型纤溶酶原激活剂（ｔＰＡ）的快速抑制剂。近年来国内大量的研究发现,ｔＰＡ、ＰＡＩ活性或含量的变化与许多疾病,特别是心、脑血管疾病密切相关,已引起专家学者日益广泛的重视［１,２］。本文就组织纤溶酶原激活剂及其抑制剂的分子…     

尿激酶型纤溶酶原激活物及其特异受体和抑制物与肺癌的浸润转移

研究尿激酶型纤溶酶原激活物(uPA)及其特异受体(uPA-R)和抑制物(PAI-1、PAI-2)在肺癌浸润转移中的作用.应用RIA分别对67例经组织病理确诊的各期肺癌和30例肺部相关炎症患者及30名健康献血者进行了相应的检测.结果显示,小细胞肺癌Ⅱ期和Ⅲ期患者血浆中uPA、uPA-R、PAI-1水平显著升高(P＜0.001),而PAI-2的水平逐渐降低;腺癌、鳞癌伴有浸润主支气管及肺门淋巴结者uPA、uPA-R与PAI-1水平亦显著升高(P＜0.001);周围型肺癌未见淋巴结受侵者uPA、uPA-R、PAI-1与PAI-2水平异常升高.uPA、uPA-R与PAI-1在肺癌中水平明显升高,并与肺癌的浸润转移相关密切,可作为肿瘤患者早期诊断、预后评估的有力指标.     

uPA/uPAR/PAI与消化系统肿瘤

消化系统肿瘤在我国的肿瘤发病率中占第1位.从尿激酶型纤溶酶原激活物受体(urokinase plasminogen activator receptor, uPAR)首次被描述为尿激酶型纤溶酶原激活物(urokinase plasminogen activator, uPA)链的细胞表面高亲和性激活剂以来,越来越受到研究者的关注.研究表明:uPA,uPAR及尿激酶型纤溶酶原激活物抑制剂(urokinase plasminogen activator inhibitor, PAI)与消化系统肿瘤侵袭和转移密切相关.本文对uPA,uPAR及PAI与胃癌、食管癌、结肠癌、肝癌、胰腺癌等侵袭与转移的关系进行综述.     

Prognostic relevance of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitors PAI-1 and PAI-2 in gastric cancer

Expression of urokinase-type plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1) and plasminogen activator inhibitor-2 (PAI-2) was evaluated in 125 surgically resected gastric cancers by immunohistochemical analysis. Tissue was stained immunohistochemically with a monoclonal antibody against human uPA and monoclonal antibodies against human PAI-1 and PAI-2. In addition, DNA ploidy patterns were determined by cytofluorometer after staining with propidium iodide. We found that 82 (66%) of the 125 gastric cancers expressed uPA as diffuse cytoplasmic staining, as intensely outlined luminal borders. PAI-1 expression was observed in 62 (50%) of 125 gastric cancer as a fine, diffuse and granular pattern in the cytoplasm. PAI-2 expression was observed in 65 (52%) of the 125 gastric cancers as a diffuse cytoplasmic staining. uPA-positive tumours showed a higher incidence of infiltration, lymph node metastasis and peritoneal dissemination than uPA-negative ones. Patients with uPA-positive tumours proved to have a significantly poorer prognosis than those with negative ones. PAI-1-negative tumours showed a higher incidence of liver metastasis and carried a poorer prognosis than PAI-1-positive ones. There was no significant correlation between uPA or PAI-1 expression and DNA ploidy patterns. Conversely, there was no significant relationship between PAI-2 expression and clinicopathological parameters and prognosis. According to the expression of uPA and PAI-1 status, groups of 19 uPA(–)/PAI-1(–), 44 uPA(+)/PAI-1(–), 23 uPA(–)/PAI-1(+) and 39 uPA(+)/PAI-1(+) were subdivided. Tumours with UPA(+)/PAI-1(–) had a significantly higher incidence of liver metastasis, lymph node metastasis and serosal invasion than the other groups of tumours. Patients with uPA(+)/PAI-1(–) tumours had a significantly poorer prognosis than those with uPA(–)/PAI-1(+) tumours. These results indicate that uPA expression is a useful biological prognostic indicator, and that uPA and PAI-1 may play an important part in the tumour progression and metastasis in gastric cancer.     

The urokinase-type plasminogen activator and inhibitors in resectable lung adenocarcinoma

BackgroundThe urokinase-type plasminogen activator (uPA) system is closely related to the occurrence and progression of cancer in many aspects. Previous studies demonstrated that the conclusions about the prognosis value of uPA, plasminogen activator inhibitor 1 (PAI-1) and plasminogen activator inhibitor 2 (PAI-2) in lung cancer are controversial, so this study was performed for the exploration of the predictive effect of uPA, PAI-1 and PAI-2 on the overall survival (OS) of resectable pulmonary adenocarcinoma patients.MethodsUPA, PAI-1 and PAI-2 expression levels were assayed by immunohistochemical staining based on tissue microarray (TMA) that is composed of formalin-fixed paraffin-embedded specimens from 84 resectable lung adenocarcinoma patients from July 2004 to June 2009. The relationship of IHC, mRNA expression levels of three molecules were investigated respectively. The three molecules’ relationship with clinicopathologic parameters and OS was explored by Chi-square, Kaplan-Meier, and Cox regression analyses. The Cancer Genome Atlas (TCGA) database was used to analyze differential gene expressions of RNA-sequencing data of pulmonary adenocarcinoma and normal tissues, and Kaplan-Meier methods were adopted to confirm the prognostic value of uPA, PAI-1 and PAI-2 in resectable lung adenocarcinoma in TCGA database and the R package MethylMix was used to conduct an analysis integrating methylation data and gene expression of RNA-sequencing data based on TCGA.ResultsUPA, PAI-1 and PAI-2 had much higher IHC expression levels in tumor than those in the normal tissues (uPA, Z = -10.511; PAI-1, Z = -4.836; PAI-2, Z = -6.794; all P < 0.0001). High DNA methylation level of gene uPA resulted in the decrease of its expression. In addition, expression level of PAI-2 was positively associated with tumor size (χ² = 8.372, P = 0.004). Multivariate analyses showed TNM stage III was an independent adverse prognostic factor (hazard ratio = 3.736, 95 % confidence interval = 1.097–12.72, P = 0.035). Kaplan-Meier method revealed that uPA, PAI-1 and PAI-2 expression levels were not related to the OS for 84 resectable lung adenocarcinoma patients. According to TCGA data, PAI-1 expression level was identified as a potential adverse predictor for prognosis of resectable lung adenocarcinoma (Gehan-Breslow-Wilcoxon test, P = 0.025).ConclusionsOur data show that, the expression levels of uPA, PAI-1 and PAI-2 are significantly up-regulated in resectable lung adenocarcinoma. Besides, this study highlights PAI-1 as a latent adverse prognostic factor in resectable adenocarcinoma of lung.     

Antibodies to PAI-1 alter the invasive and migratory properties of human tumour cells in vitro

Recent reports suggest that elevated levels of plasminogen activator inhibitor-1 (PAI-1) may contribute to tumour progression. The studies reported here were designed to help elucidate PAI-1's contribution to the invasive and migratory phenotype. Antibodies to PAI-1 dose-dependently, and significantly, inhibited the invasive and migratory potential of human HT1080 fibrosarcoma cells, as did an antibody to uPA and the plasmin inhibitor aprotinin. Invasion of the human melanoma cell line, BLM, was also attenuated by the anti-PAI-1 monoclonal antibody MAI-12. The non-invasive human melanoma cell line, IF6, which does not express uPA, provided further confirmation of PAI-1 and uPA's role as, upon transfection with uPA, this cell line attained an invasive phenotype, which was again attenuated by MAI- 12. Although antibodies to PAI-1 did not affect the adhesion of HT1080 cells to vitronectin, the antibody to uPA reduced their attachment. Addition of exogenous PAI-1, however, prevented HT1080 cell adhesion (IC₅₀ 180nM) and promoted cell detachment from vitronectin. Furthermore melanoma cells transfected with a uPA variant, which had an impaired interaction with PAI-1, were not invasive and had impaired binding to vitronectin. These data highlight the importance of a balanced proteolysis and suggest an additional role for PAI-1 distinct from its role in proteolysis. These data also suggest that uPA and PAI-1 may co-operate in the migratory process by respectively facilitating the attachment to, and subsequent detachment from, vitronectin in the extracellular matrix. These results support the clinical findings and indicate that modulation of PAI-1 activity may be of therapeutic benefit for the treatment of cancer. This revised version was published online in July 2006 with corrections to the Cover Date.     

Signalling networks associated with urokinase-type plasminogen activator (uPA) and its inhibitor PAI-1 in breast cancer tissues: new insights from protein microarray analysis

The urokinase-type plasminogen activator (uPA) and the main uPA inhibitor PAI-1 play important roles in cell migration and invasion in both physiological and pathological contexts. Both factors are clinically applicable predictive markers in node-negative breast cancer patients that are used to stratify patients for adjuvant chemotherapy. In addition to their classical functions in plasmin regulation, both factors are key components in cancer-related cell signalling. Such signalling cascades are well described in cell culture systems, but a better understanding of uPA- and PAI-1-associated signalling networks in clinical tissues is needed. We examined the expression of uPA, PAI-1, and 21 signalling molecules in 201 primary breast cancer tissues using protein microarrays. Expression of uPA was significantly correlated with the expression of ERK and Stat3, while expression of PAI-1 was correlated with the uPA receptor and Akt activation, presumably via integrin and HER-receptor signalling. Analysis of uPA expression did not reveal any significant correlation with staging, grading or age of the patients. The PAI-1 expression was correlated with nodal stage. Network monitoring for uPA and PAI-1 in breast cancer reveals interactions with main signalling cascades and extends the findings from cell culture experiments. Our results reveal possible mechanisms underlying cancer development.     

Potentiating effect of endothelial cells on astrocytic plasminogen activator inhibitor type-1 gene expression in an in vitro model of the blood–brain barrier

There is accumulating evidence of the importance of cellular communication between the cells that compose the blood-brain barrier (BBB). Astrocytes are known to affect the expression of tissue-type plasminogen activator (t-PA) and its inhibitor plasminogen activator inhibitor type-1 (PAI-1) in endothelial cells. We investigated the influence of endothelial cells on astrocytic gene expression of PAI-1, protease nexin-1 (PN-1) and t-PA using an in vitro model of the BBB. Primary rat astrocyte-enriched cultures were cocultured with primary adult rat brain microvascular endothelial cells on opposite sides of a transwell membrane. After coculturing for 9–11 days, the cultures were treated with lipopolysaccharide (LPS) for 8 h or 24 h. The levels of PAI-1, PN-1 and t-PA mRNA in untreated and treated monocultures and cocultures were analyzed by Real-Time RT-PCR. Cocultivation of astrocytes and endothelial cells increased astrocytic PAI-1 mRNA expression, and this response was further amplified by LPS treatment. The levels of PN-1 and t-PA mRNA expression in astrocytes were unaffected by cocultivation and/or LPS treatment. Analysis of endothelial PAI-1 and t-PA gene expression revealed increased PAI-1 mRNA levels in cocultured cells, whereas t-PA mRNA levels remained unchanged. These results demonstrate that the cocultivation of astrocytes and endothelial cells induces a pronounced increase in astrocytic PAI-1 gene expression, and that this effect is amplified by LPS treatment. These findings imply an important role for intercellular crosstalk in modulating PAI-1 gene expression within the BBB, under both physiologic and pathophysiologic conditions.     

Expression of urokinase-type plasminogen activator, urokinase-type plasminogen activator receptor, and plasminogen activator inhibitor-1 and -2 in hepatocellular carcinoma

It has become more and more clear in recent decades that the plasminogen activation system, which includes urokinase-type plasminogen activator (uPA), urokinase-type plasminogen activator receptor (uPAR), plasminogen activator inhibitor (PAI)-1 and PAI-2, plays a very important role in the aggressiveness of cancer. Using immunohistochemistry and enzyme-linked immunosorbent assay (ELISA), the expression of these four components of the uPA system was analyzed in 19 cases of hepatocellular carcinoma (HCC) and 18 cases of the adjacent non-cancer tissues which all had chronic active hepatitis with liver fibrosis or liver cirrhosis. Four cases of normal liver tissues, as controls for immunohistochemical stains, were obtained from the hepatectomized liver of patients with metastatic cancer in the liver. The positive rates of uPA, uPAR, PAI-1 and PAI-2 for immunohistochemical stains in cancer tissues were 78.9, 68.4, 57.9 and 31.6%, respectively. Positive signals were mainly distributed in the cytoplasm of the cancer and in stromal cells. Moreover, the strong stains were chiefly located in the invasive front of the cancer cells. No specific stain was detected in four cases of normal liver tissues. In ELISA, there were significant differences between cancer and non-cancer tissues in concentration of uPA, uPAR and PAI-1 (P < 0.0003, 0.0024 and 0.01, respectively), but there was no significant difference in that of PAI-2 (P = 0.37). These results suggest that uPA, uPAR and PAI-1 are related to invasion of HCC.     

胃癌中uPA、PAI-1表达及其与血管生成的关系

目的 观察胃癌组织中uPA、PAI-1mRNA及蛋白的表达，并探讨它们与肿瘤分化、血管生成及临床病理因素之间的关系。方法 用原位杂交及免疫组化S-P法检测110例胃癌组织中uPA、PAI-1的表达，根据CD34阳性的血管内皮细胞计数肿瘤组织微血管密度（MVD）。结果 （1）胃癌组织中uPA mRNA和蛋白、PAI-1 mRNA和蛋白阳性表达定位于胞质；uPA的表达随分化程度的降低有逐渐升高的趋势，PAI-1的表达随分化程度的降低有逐渐降低的趋势。（2）110例uPA mRNA及蛋白表达阳性组MVD值显著高于阴性组，差异均具有显著性（P值均＜0．05）。（3）uPA mRNA及蛋白的表达与临床分期呈正相关（P＜0．05），PAI-1的表达与临床分期和淋巴结转移无相关性。（4）uPA mRNA／蛋白与PAI-1 mRNA／蛋白的表达无相关性。结论uPA与促进胃癌的血管生成密切相关，阻断uPA的分泌和作用途径有望对胃癌浸润转移起抑制作用；胃癌组织中PAI-1可能担当重要的调节剂或者是肿瘤细胞防止自身降解的保护剂而不是这个系统的单纯抑制剂。     

多囊卵巢综合征患者血PAI-1和uPA含量的变化

目的观察多囊卵巢综合征(PCOS)患者外周血纤溶酶原激活抑制物1(PAI-1)和尿激酶型纤溶酶原激活物(uPA)的水平。方法实验分PCOS组和对照组,PCOS组又分为肥胖组和正常体重组,用酶联免疫吸附法(ELISA)测定PCOS组与对照组患者血浆PAI-1及血清uPA水平,并测定体重指数(BMI)、腰臀比(WHR)、空腹血糖(FPG)、空腹胰岛素及胰岛素释放试验(IRT),以稳态模型公式评估胰岛素抵抗(IR),并计算胰岛素曲线下面积(AUC)。结果PCOS组与对照组相比,黄体生成素/卵泡刺激素(LH/FSH)、睾酮(T)、空腹血糖、稳态(HOMA)指数、AUC及PAI-1含量均显著升高(P<0.05)。其中,PCOS肥胖组与正常体重组相比,HOMA指数、AUC及PAI-1含量也显著升高(P<0.05)。在相关性分析中,PAI-1与HOMA指数、PAI-1与AUC、PAI-1与BMI、HOMA-IR与BMI均有显著相关性(P<0.0001)。结论胰岛素抵抗和肥胖是影响PCOS患者PAI-1水平升高的一个很重要因素,抗PAI-1的研究可能为多囊卵巢综合征的治疗提供一个新的方法。