Urokinase-type plasminogen activator promotes synaptic repair in the ischemic brain

The central nervous system has a very high energy requirement. Accord- ingly, despite representing only 2% of the body＇s mass, the brain uses 20% of the total oxygen consumption. Importantly, because most of this energy is used to maintain synaptic activity, even a mild decrease in its supply to the brain has deleterious implications for synaptic function.

Urokinase-type plasminogen activator receptor as a predictor of poor outcome in patients with systemic inflammatory response syndrome

BACKGROUND:Urokinase-type plasminogen activator(uPA) and urokinase-type plasminogen activator receptor(uPAR) are known as important factors,which mediate a variety of functions in terms of vascular homeostasis,inflammation and tissue repair.However,their role in systemic inflammatory response syndrome(SIRS) has been less well studied.This study aimed to test the hypothesis that the abnormalities of fibrinolysis and degradation of extracellular matrix mediated by uPA and uPAR are directly related to the patients with SIRS.We therefore analyzed their role and clinicopathological significance in patients with SIRS.METHODS:A case-control study was conducted with 85 patients who were divided into two groups according to the diagnostic criteria of SIRS:SIRS group(n=50) and non-SIRS group(/7=35).The SIRS group was divided into MODS group(n=26) and non-MODS group(n=24) by their severity,and survival group(n=35) and non-survival group(n=15) by their prognosis.Another 30 healthy adults served as normal controls.uPA and uPAR in plasma were detected by commercial enzyme-linked immunosorbent assay(ELISA) kits.RESULTS:The plasma level of uPA was lower in the SIRS group than in the non-SIRS group and controls(P<0.001 and P<0.001).It was lower in sepsis patients and the MODS group than in the non-sepsis patients and the non-MODS patients(all P<0.05).However,there was no difference in uPA level between survivors and non-survivors(P>0.05).The plasma level of uPAR increased in the SIRS group compared with the non-SIRS group and controls(P<0.001 and P<0.001).There was a significant elevation of uPAR in sepsis patients,MODS patients and non-survivors as compared with non-sepsis patients,non-MODS patients and survivors respectively(all P<0.05).Plasma uPAR levels were positively correlated with APACHE Ⅱ score(r=0.575,P<0.001) and SOFA score(r=0.349,P=0.013).AUCs for the prediction of SIRS mortality were 0.67 and 0.51,respectively,for uPA and uPAR.CONCLUSION:uPAR could be a predictor of poor outcome in patients with SIRS.

Crystal Structures of 2-Aminobenzothiazole-based Inhibitors in Complexes with Urokinase-type Plasminogen Activator

Urokinase-type plasminogen activator （uPA） plays a crucial role in the regulation of plasminogen activation, tumor cell adhesion and migration. The inhibition of uPA activity is a promising mechanism for anti-cancer therapy. Most current uPA inhibitors employ a highly basic group （either amidine or guanidine group） to target the S1 pocket of uPA active site, which leads to poor oral bioavailability. Here we study the possibility of using less basic 2-aminobenzothiazole （ABT） as S1 pocket binding group. We report the crystal structures of uPA complexes with ABT or 2-amino-benzothiazole-6-carboxylic acid ethyl ester （ABTCE）. The inhibitory constants of these two inhibitors were measured by a chromogenic competitive assay, and it was found that ABTCE is a better inhibitor for uPA （Ki = 656 μM） than ABT （Ki = 5.03 mM）. This work shows that 2-amniobenzothiazole can be used as P1 group which may have better oral bioavailability than the commonly used amidine or guanidine group. We also found the ethyl ester group occupies the characteristic oxyanion hole and contacts to uPA 37- and 60-loops. Such work provides structural information for further improvements of potency and selectivity of this new class of uPA inhibitor.

Role of Urokinase-type Plasminogen Activator in the Precontact Sperm-egg Communication and Fertility of Mice in vitro

Objective To explore the role of urokinase-type plasminogen activator（uPA） in precontact sperm-egg communication and fertility of mice in vitro. Methods Firstly, sperm chemotaxis （SC） induced by uPA was assayed by measuring the sperm densities in capillaries with a descending gradient or no gradient of uPA respectively. Secondly, the role of uPAR that exists in sperm plasma membrane in SC was studied by examining the change of sperm density in capillary after incubating spermatozoa with anti-uPAR antibody. Thirdly, SC induced by eggs, which had been treated with uPA, PAl-1 and anti-uPAR beforehand respectively, was assayed to study the role of uPA in PSEC. Lastly, the fertilization capability of spermatozoa treated with uPA was examined by counting the number of fertilized eggs. Results 1）The density of spermatozoa that migrated down the gradient of uPA into the capillary was significantly lower than that into the capillary containing no-gradient uPA. 2） When uPAR of spermatozoa was inhibited by anti-uPAR antibody, the density of spermatozoa that migrated into the capillary with ascending gradient of uPA decreased correspondingly. 3） The density of spermatozoa attracted by eggs, which were treated with uPA beforehand, increased significantly than that of attracted by non-treated eggs. On the contrary, the sperm density decreased correspondingly when the egg was treated with PAI-1. 4） The number of fertilized eggs increased significantly after the spermatozoa used here was treated with uPA beforehand. Conclusion uPA could induce SC of mice sperm in vitro through the uPAR on its membrane, enhance the capability of egg inducing SC, and promote spermatozoa to fertilize eggs. Thus, uPA may act as an attractant in PSEC, increase the chance encounter of spermatozoa and eggs, therefore, enhance the fertility success correspondingly. This study, in some degree, provides an evidence that uPA may be used as a new medicine and diagnostic reagent for male infertility.

EXPRESSION AND SIGNIFICANCE OF UROKINASE-TYPEPLASMINOGEN ACTIVATOR IN BREAST CANCER

Objective: To study the expression and clinical significance of urokinase-type plasminogen activator (uPA) in breast cancer. Methods: Applying streptavidin-biotin complex (SABC) immunohistochemical technique, expression of uPA was studied in 100 patients with primary breast cancer. Results: There were 55 patients with high uPA expression, and 45 with lower expression. There was significant correlation between uPA expression and TNM stage, lymph node status, and the tumor size. Neither age, menopausal status, nor ER status was significantly related with level of uPA expression. The patients with high expression of uPA had significantly shorter disease-free survival (DFS) and overall survival (OS) than did those with low expression of uPA. Univariate analysis showed that uPA as a prognostic factor was of similar magnitude to lymph node status and TNM stage, but stronger than that of ER status and tumor size. UPA was an independent prognostic factor affecting disease-free survival and overall survival. Conclusion: uPA appears to be a strong and independent biologic marker for predicting prognosis of breast cancer.

Crystal Structures of Urokinase-type Plasminogen Activator in Complex with 4-(Aminomethyl) Benzoic Acid and 4-(Aminomethyl-phenyl)-methanol

Urokinase-type plasminogen activator （uPA） is a trypsin-like serine protease and plays a key role in several biological processes, including tissue remodeling, cell migration, and matrix degradation. The inhibitors of uPA have been shown to prevent the spread of metastasis and tumor growth, and accordingly uPA is widely recognized as a target for the treatment of cancer. In this work, we report the crystal structures of the complexes of uPA with its inhibitors： 4- （aminomethyl）-benzoic acid （AMBA） and 4-（aminomethyl-phenyl）-methanol （AMPM）, both at a resolution of 2.35 А. The inhibitory constants of these two inhibitors were measured by a chromogenic competitive assay, and it was found that AMBA is a better inhibitor for uPA （Ki = 2.68 mM） than AMPM （Ki = 13.99 mM）. The structural study shows that the binding mode of inhibitor AMBA on uPA is similar to that of AMPM on uPA, both docked into the active site S1 pocket of uPA. Structural details of these complexes are provided to explain the difference of inhibitory constants.

The plasminogen activating system in the pathogenesis of Alzheimer’s disease

Dementia is a clinical syndrome that affects approximately 47 million people worldwide and is characterized by progressive and irreversible decline of cognitive,behavioral and sesorimotor functions.Alzheimer’s disease(AD)accounts for approximately 60–80%of all cases of dementia,and neuropathologically is characterized by extracellular deposits of insoluble amyloid-β(Aβ)and intracellular aggregates of hyperphosphorylated tau.Significantly,although for a long time it was believed that the extracellular accumulation of Aβwas the culprit of the symptoms observed in these patients,more recent studies have shown that cognitive decline in people suffering this disease is associated with soluble Aβ-induced synaptic dysfunction instead of the formation of insoluble Aβ-containing extracellular plaques.These observations are translationally relevant because soluble Aβ-induced synaptic dysfunction is an early event in AD that precedes neuronal death,and thus is amenable to therapeutic interventions to prevent cognitive decline before the progression to irreversible brain damage.The plasminogen activating(PA)system is an enzymatic cascade that triggers the degradation of fibrin by catalyzing the conversion of plasminogen into plasmin via two serine proteinases:tissue-type plasminogen activator(tPA)and urokinase-type plasminogen activator(uPA).Experimental evidence reported over the last three decades has shown that tPA and uPA play a role in the pathogenesis of AD.However,these studies have focused on the ability of these plasminogen activators to trigger plasmin-induced cleavage of insoluble Aβ-containing extracellular plaques.In contrast,recent evidence indicates that activity-dependent release of uPA from the presynaptic terminal of cerebral cortical neurons protects the synapse from the deleterious effects of soluble Aβvia a mechanism that does not require plasmin generation or the cleavage of Aβfibrils.Below we discuss the role of the PA system in the pathogenesis of AD and the translational relevance of data published to this date.

Chemotactic effect of urokinase-type plasminogen activator on mouse spermatozoa in vitro

The aim of this study is to investigate the che-motactic effect of urokinase-type plasminogen activator(uPA)on mouse spermatozoa.Capillary assays were applied to study the chemotactic activity of ascending and descending gradients of uPA.Firstly,the chemotactic effect of an ascending gradient of uPA on mouse sper-matozoa was observed by counting the number of sper-matozoa that migrated into the capillary after incubation with uPA for 5,10,20,and 30 min,respectively,com-pared with that after incubation with F10.Twenty min-utes was a suitable incubation time to obtain a plateau of sperm accumulation.Meanwhile,to confirm the specific effect of uPA on mouse sperm chemotaxis,uPA inhibitor(PAI-1)and anti-uPAR rabbit IgG were added to the test solution containing 20 U/mL uPA,respectively.To exclude the possibility that PAI-1 and anti-uPAR rabbit IgG may affect sperm accumulation nonspecifically,PAI-1 and anti-uPAR rabbit IgG were added to F10,respect-ively.It was found that the chemotactic effect of uPA was neutralized completely by PAI-1 and anti-uPAR rabbit IgG.PAI-1 and anti-uPAR rabbit IgG had no neutral-izing effect on the sperm chemotactic effect.Lastly,the sperm chemotaxis response to a descending gradient of uPA was also observed.Taken together,the results sug-gest that uPA can induce sperm chemotaxis in vitro by binding to its receptor on the sperm membrane and may act as a chemoattractant in precontacting sperm-egg com-munication thereby increasing the chance encounter of spermatozoa and eggs.

胃癌组织Maspin,uPA,MMP-7表达的意义

目的:观察胃癌及正常胃黏膜Maspin,uPA, MMP-7表达的意义．方法:应用免疫组化SP法检测胃管状腺癌30 例,胃印戒细胞癌30例,正常胃黏膜组织20例中Maspin,uPA,MMP-7的表达情况．结果:在胃管状腺癌中Maspin,uPA,MMP-7 阳性表达率分别为50％,70％和80％;胃印戒细胞癌中阳性表达率分别为46．7％,76．7％和 90％;正常胃黏膜组织中阳性表达率分别为 90％,35％和30％．Maspin的表达与浸润深度、淋巴结转移相关,而与肿块的大小和TNM分期无关．uPA和MMP-7的表达与浸润深度、淋巴结转移、TNM分期相关,而与肿块的大小无关．Maspin的表达与uPA和MMP-7的表达呈负相关(P=0．012,r=-0．322;P=0．008,r= -0．341);uPA的表达与MMP-7的表达呈正相关 (P=0．034,r=0．274)．结论:Maspin在胃癌中表达下调,uPA和 MMP-7在胃癌中过表达,他们在胃癌的浸润转移中起重要作用,可作为反应胃癌病理生物学行为的有效指标．

二种溶栓剂应用致死亡的病例分析

目的分析2005～2009年期间本院应用重组组织型纤溶酶原激活剂(rt-PA)和尿激酶(UK)静脉溶栓治疗患者的院内死亡发生情况。方法对应用rt-PA或UK溶栓治疗的ST段抬高的急性心肌梗死患者(n=57)和肺血栓栓塞症患者(n=60)的溶栓剂应用情况、死亡原因等进行回顾分析研究。结果117例接受溶栓治疗的患者院内死亡10例(8.5%),原因为心源性休克(6例)、心脏破裂(3例)和心室颤动(1例)。10例死亡患者中,无1例因出血并发症死亡;7例为ST段抬高的急性心肌梗死患者,肺血栓栓塞症患者因心源性休克死亡3例。应用rt-PA溶栓治疗的98例(84%)患者院内死亡7例,19例患者接受UK溶栓治疗,死亡3例。结论接受溶栓治疗患者的院内死因主要与基础疾病相关,科学规范的应用溶栓治疗是安全的。

The uPA/uPAR system in astrocytic wound healing

The repair of injured tissue is a highly complex process that involves cell prolife ration,differentiation,and migration.Cell migration requires the dismantling of intercellular contacts in the injured zone and their subsequent reconstitution in the wounded area.Urokinase-type plasminogen activator(u PA)is a serine proteinase found in multiple cell types including endothelial cells,smooth muscle cells,monocytes,and macrophages.A substantial body of experimental evidence with different cell types outside the central nervous system indicates that the binding of uPA to its receptor(uPAR)on the cell surface prompts cell migration by inducing plasmin-mediated degradation of the extracellular matrix.In contrast,although uPA and uPAR are abundantly found in astrocytes and u PA binding to uPAR triggers astrocytic activation,it is unknown if uPA also plays a role in astrocytic migration.Neuronal cadherin is a member of cell adhesion proteins pivotal for the formation of cell-cell conta cts between astrocytes.More specifically,while the extracellular domain of neuronal cadherin interacts with the extracellular domain of neuronal cadherin in neighboring cells,its intracellular domain binds toβ-catenin,which in turn links the complex to the actin cytos keleton.Glycogen synthase kinase 3βis a serine-threonine kinase that prevents the cytoplasmic accumulation ofβ-catenin by inducing its phosphorylation at Ser33,Ser37,and Ser41,thus activating a sequence of events that lead to its proteasomal degradation.The data discussed in this perspective indicate that astrocytes release u PA following a mechanical injury,and that binding of this u PA to uPAR on the cell membrane induces the detachment ofβ-catenin from the intracellular domain of neuronal cadherin by triggering its extracellular signal-regulated kinase 1/2-mediated phosphorylation at Tyr650.Remarkably,this is followed by the cytoplasmic accumulation ofβ-catenin because uPA-induced extracellular signalregulated kinase 1/2 activation also phosphorylates lipoprotein receptor-related protein 6 at Ser1490,which in turn,by recruiting glycogen synthase kinase 3βto its intracellular domain abrogates its effect onβ-catenin.The cytoplasmic accumulation ofβ-catenin is followed by its nuclear translocation,where it induces the expression of uPAR,which is required for the migration of astrocytes from the injured edge into the wounded area.

Simvastatin Prevents Lipopolysaccharide-induced Septic Shock in Rats

Simvastatin is a hypolipidemic drug that inhibits hydroxymethylglutaryl coenzyme A（HMGCoA） reductase to control elevated cholesterol,or hypercholesterolemia.Previous studies have shown that simvastatin may attenuate inflammation in ischemia-reperfusion injury and sepsis.Herein,we hypothesized that simvastatin may prevent rats from lipopolysaccharide（LPS）-induced septic shock.In our study,rats were divided into a saline group,an LPS group and an LPS plus simvastatin group.Male Sprague-Dawley（SD） rats were pretreated with simvastatin（1 mg/kg） for 30 min before the addition of LPS（8 mg/kg）,with variations in left ventricular pressure recorded throughout.Ninety min after LPS injection,whole blood was collected from the inferior vena cava,and neutrophils were separated from the whole blood using separating medium.The neutrophils were then lysed for Western blotting to detect the levels of urokinase-type plasminogen activator（u PA） and plasminogen activator inhibitor-1（PAI-1）.In addition,mesentery microcirculations of inlet diameter,outlet diameter and blood flow rate were measured in all three groups.The results indicated that simvastatin significantly promoted heart systolic function and increased the level of u PA while simultaneously inhibited the expression of PAI-1 as compared with LPS group.Moreover,simvastatin reversed the LPS-induced inhibition of mesentery microcirculation.Taken together,it was suggested that simvastatin can effectively protect the rats from LPS-induced septic shock.

CLINICAL STUDY OF T-PA AND U-PA EXPRESSION IN PATIENTS WITH GASTROINTESTINAL CANCER

Objective: To study the changes of tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA) expressions and fibrinolysis molecular markers in patients with gastrointestinal cancer in order to elucidate their clinical significance. Methods: The plasma levels of t-PA, u-PA, urokinase-type plasminogen activator receptor (u-PAR) and plasmin anti-plasmin complex (PAP) were measured by ELISA. t-PA and u-PA mRNAs were detected by Real-time RT-PCR. Results: The plasma levels of u-PA, u-PAR and PAP were elevated in gastrointestinal cancer patients, while u-PA was markedly elevated in patients with local infiltration, lymph node involvement or distal metastasis. U-PA mRNA was higher and t-PA was lower in gastrointestinal cancer compared to normal tissue. Conclusion: Hyperfibrinolysis is an important factor related with metastasis potential of gastrointestinal cancer. t-PA may be a character of well differentiated tissue.

Effect of Lanthanum and Cerium on Expression of RSCU-PA-32k Gene in Saccharomyces Cerevisiae

Lanthanum chloride can promote expression efficiency of rscu-PA-32k gene in yeast. 2 and 5 mmol·L -1 LaCl 3 increase the activities of the expression product by 13% and 20% (from 14.6 to 16.5 and 17.5 U·ml -1). Cerium chloride can decrease the activity of expression product. 2 and 5 mmol·L -1 CeCl 3 decreases the activities of the expression product by 21% and 33% (from 14.6 to 11.5 and 9.8 U·ml -1).

C4.4A as a biomarker in pulmonary adenocarcinoma and squamous cell carcinoma

The high prevalence and mortality of lung cancer, together with a poor 5-year survival of only approximately 15%, emphasize the need for prognostic and predictive factors to improve patient treatment. C4.4A, a member of the Ly6/uP AR family of membrane proteins, qualifies as such a potential informative biomarker in non-small cell lung cancer. Under normal physiological conditions, it is primarily expressed in suprabasal layers of stratified squamous epithelia. Consequently, it is absent from healthy bronchial and alveolar tissue, but nevertheless appears at early stages in the progression to invasivecarcinomas of the lung, i.e., in bronchial hyperplasia/metaplasia and atypical adenomatous hyperplasia. In the stages leading to pulmonary squamous cell carcinoma, expression is sustained in dysplasia, carcinoma in situ and invasive carcinomas, and this pertains to the normal presence of C4.4A in squamous epithelium. In pulmonary adenocarcinomas, a fraction of cases is positive for C4.4A, which is surprising, given the origin of these carcinomas from mucin-producing and not squamous epithelium. Interestingly, this correlates with a highly compromised patient survival and a predominant solid tumor growth pattern. Circumstantial evidence suggests an inverse relationship between C4.4A and the tumor suppressor LKB1. This might provide a link to the prognostic impact of C4.4A in patients with adenocarcinomas of the lung and could potentially be exploited for predicting the efficacy of treatment targeting components of the LKB1 pathway.

肝硬化患者纤溶酶原激活物以及基质金属蛋白酶抑制剂蛋白表达

[目的]探讨肝纤维化不同分级α-平滑肌肌动蛋白(α-SMA)、基质金属蛋白酶1(MMP-1)、基质金属蛋白酶抑制剂1(TIMP-1)蛋白表达以及血浆尿激酶型纤溶酶原激活物(uPA)、纤溶酶原激活物抑制剂1(PAI-1)变化在肝纤维化发生发展中的意义.[方法]慢性肝病患者37例,依据病理变化分为0～4级,其中1级8例,2级9例,3级7例,4级13例;正常对照组6例.免疫组化法测定肝组织α-SMA、MMP-1、TIMP-1蛋白表达.ELISA法测定血浆uPA、PAI-1、转化生长因子β1(TGF-β1)变化.并同时检测血透明质酸、血清清蛋白、凝血酶原时间及其活动度、胆红素改变.[结果]随着肝纤维化的发展,肝组织α-SMA、MMP-1、TIMP-1蛋白表达以及血浆uPA、PAI-1、TGF-β1水平逐渐增加.在肝纤维化3、4级α-SMA、TIMP-1蛋白表达、血浆PAI-1水平增加尤为明显,而血浆uPA水平、肝组织MMP-1蛋白表达差异无统计学意义,表现为uPA、MMP-1相对不足.在肝纤维化4级血浆TGF-β1与α-SMA蛋白表达呈正相关(P＜0.05),α-SMA蛋白表达与PAI-1、TIMP-1蛋白表达呈正相关(均P＜0.05).[结论]肝组织TIMP-1蛋白表达以及血浆PAI-1在肝硬化发展过程中发挥着重要作用.抑制TGF-β1的早期激活,抑制肝星状细胞激活与PAI-1过度表达,适当增加MMP-1表达,可能有助于增加肝细胞外基质降解,从而延缓肝硬化的发生发展.

Urokinase-targeted recombinant bacterial protein toxins-a rationally designed and engineered anticancer agent for cancer therapy

Urokinase-targeted recombinant bacterial protein toxins are a sort of rationally designed and engineered anticancer recombinant fusion proteins representing a novel class of agents for cancer therapy.Bacterial protein toxins have long been known as the primary virulence factor(s)for a variety of pathogenic bacteria and are the most powerful human poisons.On the other hand,it has been well documented that urokinase-type plasminogen activator(uPA)and urokinase plasminogen activator receptor(uPAR),making up the uPA system,are overexpressed in a variety of human tumors and tumor cell lines.The expression of uPA system is highly correlated with tumor invasion and metastasis.To exploit these characteristics in the design of tumor cell-selective cytotoxins,two prominent bacterial protein toxins,i.e.,the diphtheria toxin and anthrax toxin are deliberately engineered through placing a sequence targeted specifically by the uPA system to form anticancer recombinant fusion proteins.These uPA system-targeted bacterial protein toxins are activated selectively on the surface of uPA systemexpressing tumor cells,thereby killing these cells.This article provides a review on the latest progress in the exploitation of these recombinant fusion proteins as potent tumoricidal agents.It is perceptible that the strategies for cancer therapy are being innovated by this novel therapeutic approach.