Transforming growth factor beta1, urokinase-type plasminogen activator and plasminogen activator inhibitor-1 mRNA expression in head and neck squamous carcinoma and normal adjacent mucosa

BACKGROUND: A balance between urokinase-type plasminogen activator (uPA) and its main inhibitor type-1 (PAI-1) appears to be important for cancer invasive behavior. Since uPA/PAI-1 system seems to be regulated by transforming growth factor beta1 (TGFbeta1) in different cell types, our aim was to investigate the relationship between the expression of the three genes and lymph node status in head and neck squamous cell carcinomas (HNSCC) at specific sites. MATERIALS AND METHODS: uPA, PAI-1, and TGFbeta1 mRNAs were determined by Northern analysis in tumor, and paired normal mucosa samples were obtained from 91 operable HNSCC patients. RESULTS: In oral cavity, excluding tongue, TGFbeta1, PAI-1, and uPA mRNAs values were consistently lower in the normal tissues than in tumors. In larynx tumors, TGFbeta1 expression was increased, but no statistically significant differences were found for uPA or PAI-1 mRNAs as compared with normal tissues. Tongue tumors overexpressed only uPA mRNA, and uPA levels showed significant parallel variations with TGFbeta1 and PAI-1 mRNAs mainly in pN+ tumors. In oral cavity tumors, an inverse correlation between TGFbeta1 and uPA was observed in pN0 subgroup, elevated uPA mRNA was counterbalanced by high PAI-1 mRNA TGFbeta1, and PAI-1 were not coordinately expressed. Correlations between the three markers were not found in larynx. Hypopharynx tumors, all staged as pN+, expressed the lowest TGFbeta1 mRNA mean values. CONCLUSIONS: Combined information about TGFbeta1, uPA, and PAI-1 mRNAs may add some clues to the understanding of the pathophysiological role of uPA system in head and neck squamous cell carcinoma.     

封闭负压引流技术对创面愈合过程纤溶酶原激活剂级联表达的影响

目的研究封闭负压引流技术对急慢性创面纤溶酶原激活剂(plasminogen activator,PA)级联中尿激酶型纤溶酶激活剂(urokinase-type plaminogen activator,uPA)和尿激酶型纤溶酶激活剂受体(urokinase-type plasminogen activator receptor,uPA)表达的影响。方法雄性小家猪5头,背部两侧形成急性创面,分为实验组和对照组,仅实验组动物接受封闭负压引流治疗。分别在治疗前和治疗后第1、3、6、9、12、18、25天于创缘切取标本,用兔抗人uPA和uPAR单克隆抗体按ABC程序进行免疫组织化学染色,并计算uPAA和uPAR的标记指数。人慢性创面6例,清创后进行持续封闭负压引流治疗,在治疗后第13、、5、7天采集创面渗出液,并用ELISA法检测渗出液中uPA和uPAR的含量。结果猪急性创面在封闭负压引流治疗后uPA和uPAR均增加,在第3天达到高峰,然后急速下降,但实验组的基因表达量和染色强度均显著高于对照组。6例人慢性创面进行治疗前uPA和uPAR表达较多,随着治疗时间的延长而逐渐减少。结论封闭负压引流治疗既能上调急性创面伤口周围的表皮角质形成细胞的uPA和uPAR表达,使之迅速增殖迁移;又能通过抑制慢性创面uPA和uPAR表达,从而减少细胞外基质的降解。     

Differential effects of acute and chronic wound fluids on urokinase-type plasminogen activator, urokinase-type plasminogen activator receptor, and tissue-type plasminogen activator in cultured human keratinocytes and fibroblasts

The effect of wound fluids collected from acute well-healing wounds and chronic nonhealing venous leg ulcers on the plasminogen activation system of keratinocyte and fibroblast cell cultures was studied in a simplified wound-healing model. Acute wound fluid was collected from donor sites of split skin grafts at different time points representing the progressive healing of the wound. Urokinase-type plasminogen activator, tissue-type plasminogen activator, urokinase-type plasminogen activator receptor, and plasminogen activator inhibitor 1 expression were studied. The methods used were immunocapture assay and immunocytochemistry. The results indicated that the later the acute wound fluid was collected, the greater the urokinase-type plasminogen activator and the lower the plasminogen inhibitor-1 level in treated cells. In contrast, the level of urokinase-type plasminogen activator receptor remained stable irrespective of wound fluid treatment. Immunostaining for urokinase-type plasminogen activator of acute wound fluid-treated cells showed a disseminated punctate pattern over the cell surface, but with chronic wound fluid, urokinase-type plasminogen activator was localized to focal contacts. Our findings support the view that in the acute wound environment the plasminogen activator system is proteolytically active and that in chronic leg ulcers urokinase-type plasminogen activator and urokinase-type plasminogen activator receptor may also be organized for cell adhesion and migration.     

IL-8-stimulated expression of urokinase-type plasminogen activator in human skin and human epidermal cells

Extracellular matrix (ECM) remodeling is essential for normal development and tissue repair. Although many roles for extracellular proteinases in the breakdown of ECM have been established, the regulations of these proteinases in human tissue are not fully understood. Inflammatory cytokines have been implicated in the regulation of several matrix metalloproteinases. To determine whether these mediators have a similar effect on fibrinolysis and the remodeling of the fibrin provisional matrix, we examined the role of cytokines on the regulation of urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) in human skin. In this report, we show that interleukin-8 (IL-8), but not other cytokines tested, is a potent inducer of the 38-kDa uPA in organ-cultured human skin. In addition, the uPA inhibitor, PAI-1, was not affected by IL-8. When primary epidermal human keratinocytes were treated with IL-8, 55-kDa pro-uPA was significantly induced in the conditioned medium. The mRNA expression of uPA in the keratinocytes was found to be constitutively elevated and was not affected by IL-8. To support such a notion, activation of the 5'-flanking promoter of the human uPA gene was measured using the CAT reporter assay. Consistent with the results of mRNA measurement, the promoter is constitutively active in keratinocytes and is not affected by IL-8. In contrast, the promoter construct is neither active in the dermal fibroblasts nor stimulated by the cytokine. This differential transactivation of uPA gene in these cells indicates that keratinocyte-specific factors may govern the basal expression of the gene. These results indicate a complex regulation of uPA expression in epidermal cells.     

尿激酶受体在尿激酶诱导小鼠精子趋化运动中的作用

目的研究尿激酶受体(uPAR)在尿激酶(uPA)诱导精子趋化运动中的作用。方法采用精子聚集毛细管内法检测精子趋化性。实验分为对照组和处理组,处理组又根据uPAR抗体浓度的不同分为10、50、100μg/ml 3组。各组毛细管内的液体都是浓度相同的uPA;对照组精子培养皿内的液体为精子悬液与Ham’s F-10的混合液,处理组精子培养皿内液体是在对照组的基础上加有不同浓度的抗-uPAR抗体。分别在实验的第203、0 min检测每组毛细管内聚集的精子数量。结果随着uPAR抗体浓度的增加,uPA趋化精子的数目逐渐减少,与对照组之间差异有显著性(P<0.05)。抗-uPAR抗体与精子作用20 min时对精子趋化运动的抑制最明显,其中50、100μg/ml组与对照组比较,P<0.01。结论阻断精子uPAR可以抑制由uPA诱导的精子趋化运动,推测uPAR可能在精卵识别中起一定的作用。     

Aldosterone modulates plasminogen activator inhibitor-1 and glomerulosclerosis in vivo

BACKGROUND: Aldosterone promotes nephrosclerosis in several rat models, whereas aldosterone receptor antagonism blunts the effect of activation of the renin-angiotensin-aldosterone system (RAAS) on nephrosclerosis, independent of effects on blood pressure. Based on recent findings linking activation of the RAAS with impaired fibrinolytic balance, we hypothesized that aldosterone induces sclerosis through effects on plasminogen activator inhibitor-1 (PAI-1), the major physiological inhibitor of plasminogen activation. METHODS: We examined the effect of aldosterone antagonism on the development of sclerosis and on renal PAI-1 expression following radiation injury in the rat. Following a single dose of 12 Gy to the kidneys, male Sprague-Dawley rats were treated with placebo, the aldosterone antagonist spironolactone (4.5 mg/day by time-release subcutaneous pellet), the angiotensin type 1 receptor antagonist L158-809 (AT1RA; 80 mg/L drinking water), or combined spironolactone and AT1RA. RESULTS: Rats treated with placebo developed significant proteinuria and nephrosclerosis 12 weeks following radiation associated with hypertension. Kidney PAI-1 mRNA expression was increased eightfold (P < 0.001 vs. nonradiated controls). Spironolactone alone had no effect on blood pressure (systolic blood pressure 149.0 +/- 5.4 mm Hg) compared with placebo (151.6 +/- 11.2 mm Hg, P = NS), whereas AT1RA alone (107.7 +/- 8.9 mm Hg, P = 0.013 vs. placebo) or in combination therapy (102.1 +/- 6.2 mm Hg, P = 0.001 vs. placebo) lowered blood pressure. Both the AT1RA and spironolactone decreased proteinuria following radiation (P < 0.001 vs. placebo for either drug), and the combination of AT1RA + spironolactone had a greater effect on proteinuria than spironolactone alone (P = 0.003). Aldosterone antagonism significantly decreased (P = 0.016 vs. placebo) and AT1RA virtually abolished (P = 0.001 vs. placebo) the development of sclerosis. Spironolactone significantly decreased PAI-1 mRNA expression in the kidneys of radiated animals (PAI-1 mRNA/GAPDH ratio 0.39 +/- 0.13 vs. placebo 0.84 +/- 0.05, P = 0.006), and there was a significant correlation between the degree of sclerosis and the level of PAI-1 immunostaining within individual rats (R2 = 0.97, P < 0.0001). CONCLUSION: This study is, to our knowledge, the first to demonstrate that aldosterone regulates PAI-1 expression in vivo, and supports the hypothesis that aldosterone induces renal injury through its effects on PAI-1 expression.     

尿激酶型纤溶酶原激活因子及其受体在神经母细胞瘤中的表达及其意义

目的：研究尿激酶型纤溶酶原活因子（uPA)及其受体（uPAR）在神经母细胞瘤（NB）中的表达和意义。方法：应用免疫组织化学方法研究uPA及uPAR在42例神经母细胞瘤中的表达，并应用逆转录-聚合酶链式反应（RT－PCR）方法检测患儿骨髓和外周血中的神经蛋白基因产物9．5（PGP9．5）。结果：uPA及uPAR阳性表达主在进展期肿瘤（均为85．7％）高于局灶期肿瘤（42．9％，28．6％）；预后不良型患儿（91．7％，83．3％）高于预后良好型患儿（均为44．4％），且差异均具有非常显著性（P＜0．01）。患儿骨髓和外周血中PGP9．5阳性检出率在uPA阳性患儿组（60．0％）显著高于uPA阴性患儿组（8．3％，P＜0．01）；uPAR阳性组（57．1％）高于uPAR阴性组（21．4％，P＜0．05）。uPA和uPAR同时阳性的10例患儿，骨髓和外周血中均有PGP9．5阳性表达，而同时阴性的5例患儿中，均未检测到PGP9．5。结论：uPA和uPAR在NB的浸润转移过程中发挥重要的作用。     

Angiotensin IV stimulates plasminogen activator inhibitor-1 expression in proximal tubular epithelial cells.

BACKGROUND: Angiotensin II (Ang II) has been shown to be implicated in the development of renal fibrosis in several forms of chronic glomerulonephritides, but the precise mechanisms of its effects remain unclear. It has recently been reported that Ang II stimulates the expression of plasminogen activator inhibitor-1 (PAI-1) in several cell lines. PAI-1 is a major physiological inhibitor of the plasminogen activator/plasmin system, a key regulator of fibrinolysis and extracellular matrix (ECM) turnover. PAI-1 induction by Ang II in endothelial cells seems to be mediated by Ang IV via a receptor that is different from Ang II type 1 and 2 receptors (AT1 and AT2). METHODS: In this study, we sought to evaluate the effects of Ang IV on PAI-1 gene and protein expression in a well-characterized and immortalized human proximal tubular cell line (HK2) by Northern blot and enzyme-linked immunosorbent assay. RESULTS: Ang IV stimulated PAI-1 mRNA expression, whereas it did not induce a significant increase in tritiated thymidine uptake after 24 hours of incubation. This effect was dose and time dependent. Ang IV (10 nM) induced a 7.8 +/- 3.3-fold increase in PAI-1 mRNA expression. The PAI-1 antigen level was significantly higher in conditioned media and the ECM of cells treated with Ang II and Ang IV than in control cells (both P < 0.02). Although Ang II induced a 4.2 +/- 2. 1-fold increase in PAI-1 mRNA expression, its effect underwent a dose-dependent reduction when amastatin, a potent inhibitor of the endopeptidases that catalyzes the conversion of Ang II to Ang IV, was added. In contrast, amastatin was not able to prevent the expression of PAI-1 mRNA induced by Ang IV. Finally, pretreatment of HK2 cells with losartan and N-Nicotinoyl-Tyr-N3-(Nalpha-CBZ-Arg)-Lys-His-Pro-Ile, the specific antagonists of AT1 and AT2 receptors, failed to modify PAI-1 mRNA expression as induced by Ang II. CONCLUSIONS: Our results demonstrate that Ang II stimulates PAI-1 mRNA expression and the production of its protein in human proximal tubular cells. This is mainly-if not exclusively-due to Ang IV, which acts on a receptor that is different than AT1 or AT2. Therefore, it can be hypothesized that the induction of PAI-1 by Ang IV may be implicated in the pathogenesis of renal interstitial fibrosis in several forms of chronic glomerulonephritides.     

转化生长因子β1对系膜细胞纤溶酶原激活物抑制物1表达的影响

目的观察转化生长因子(TGF)β1对肾小球系膜细胞(GMC)纤溶酶原激活物抑制物(PAI)-1表达的影响,并探讨反应性氧基(ROS)在TGF-β1诱导的PAI-1表达中的作用。方法体外培养大鼠GMC,分别用TGF-β1(2ng/ml)和葡萄糖氧化酶(GO)(10mU/ml)刺激,并用BSO和抗氧化剂N-乙酰半胱氨酸(NAC)进行干预处理。采用Western印迹检测PAI-1蛋白表达;RT-PCR和Northern杂交检测PAI-1mRNA表达;合成的荧光素纤溶酶底物测定纤溶酶活性。结果外源性TGF-β1和GO可显著上调大鼠系膜细胞PAI-1蛋白和mRNA的表达并降低纤溶酶活性。BSO可显著增强TGF-β1和GO诱导的系膜细胞PAI-1mRNA的表达;而NAC可显著地逆转由TGF-β1和GO诱导的PAI-1mRNA表达的上调作用。结论TGF-β1可显著上调系膜细胞PAI-1的表达并抑制纤溶酶活性。ROS在TGF-β1诱导的系膜细胞PAI-1表达上调的信号传递途径中可能起了信号传递分子的作用。     

Expression of urokinase-type plasminogen activator, urokinase-type plasminogen activator receptor and plasminogen activator inhibitors in patients with renal cell carcinoma: correlation with tumor associated macrophage and prognosis

PURPOSE: Urokinase-type plasminogen activator (uPA) has an important role in tumor progression through the degradation of extracellular matrix. In addition, uPA receptor (uPAR) and plasminogen activator inhibitors (PAIs), composed of PAI-1 and 2, are also known to affect such activities. Tumor associated macrophage (TAM) is an important regulator of tumor progression that is associated with the uPA system in various cancers. However, to our knowledge the clinical significance of PAI-2 and the relationship between the uPA system and TAM in human renal cell carcinoma (RCC) tissues have not been investigated. We investigated and clarified these issues. MATERIALS AND METHODS: The subjects of the current study were 106 consecutive surgically resected specimens from patients with RCC. The expression of uPA, uPAR, PAI-1 and PAI-2 was determined by immunohistochemistry. We also examined the relationships among these molecules, survival and TAM. RESULTS: The mean immunoreactive scores (range 0 to 6) of uPA, uPAR, PAI-1 and PAI-2 were 3.09, 2.22, 1.99 and 0.56, respectively. These scores correlated with the grade and presence of metastasis. The expression of uPA, uPAR and PAI-1 but not PAI-2 correlated negatively with cause specific survival. Of uPA family members multivariate analysis showed that PAI-1 independently influenced cause specific survival. TAM counts correlated with PAI-1 only (p <0.001). CONCLUSIONS: Our results suggest that PAI-1 is an important regulator of tumor progression and survival, and PAI-1 may modulate them via TAM. On the other hand, PAI-2 has a minimum role in survival. Our results may help discussions of treatment strategy in patients with RCC.     

Modulation of angiotensin II and norepinephrine-induced plasminogen activator inhibitor-1 expression by AT1a receptor deficiency

Angiotensin (Ang) II stimulates plasminogen activator inhibitor-1 (PAI-1) expression in many cell types by mechanisms that are cell-type specific. We measured effects of Ang II or norepinephrine on PAI-1 expression in wild type (WT) and Ang type-1a receptor knockout mice (AT(1a)-/-) in the presence or absence of the non-specific AT(1) antagonist losartan. Ang II and norepinephrine increased systolic blood pressure equally, whereas losartan decreased the pressor response of the former but not the latter in WT mice. In AT(1a)-/- mice, baseline systolic blood pressure was lower with no effect of Ang II, norepinephrine, or losartan. Ang II stimulated PAI-1 expression in the heart, aorta, and kidney and markedly in the liver of WT mice. In AT(1a)-/- mice, Ang II-stimulated PAI-1 was significantly attenuated compared with the WT in the heart and aorta but significantly enhanced in the kidney. Losartan decreased the induction in the aorta and liver of WT, and in the kidney and liver of AT(1a)-/- mice. Norepinephrine increased PAI-1 expression in WT heart and aorta, and in AT(1a)-/- heart, kidney, and liver with no effect of losartan. Renal PAI-1 expression correlated with AT(1b) receptor mRNA. We conclude that Ang II stimulates PAI-1 expression in part through the AT(1b) receptor in the kidney and liver. Further, norepinephrine induces PAI-1 expression in vivo with AT(1a) receptor deficiency modulating the effect.     

The plasminogen activator inhibitor-1 gene, hypofibrinolysis, and osteonecrosis

In 59 patients with osteonecrosis of the hip, four genes associated with thrombophilia or hypofibrinolysis along with coagulation tests were studied to determine the pathoetiologic associations of heritable coagulation disorders with osteonecrosis. Patients did not differ from healthy control subjects for the thrombophilic Factor V Leiden, prothrombin, or methylenetetrahydrofolate reductase mutations. The plasminogen activator inhibitor-1 gene was shifted toward homozygosity for the 4G polymorphism; 41% of patients with osteonecrosis were homozygous for the 4G/4G polymorphism versus 20% of 40 healthy control subjects. The gene product of the 4G polymorphism, hypofibrinolytic plasminogen activator inhibitor activity, was higher in patients than in control subjects (median 19.2 versus 6.3 U/mL); 61% of patients had high plasminogen activator inhibitor activity (> or = 16.4 U/mL) versus 5% of control subjects. Stimulated tissue plasminogen activator activity (inhibited by plasminogen activator inhibitor activity) was lower in patients than in control subjects (3.10 versus 5.98 IU/mL); 31% of patients had low stimulated tissue plasminogen activator activity (< 2.28 IU/mL) versus 3% of control subjects. Heritable hypofibrinolysis conferred by the 4G/4G mutation of the plasminogen activator inhibitor-1 gene seems to be a major pathoetiology of primary osteonecrosis.     

Leptin and plasminogen activator inhibitor-1 levels in children on chronic dialysis

Abstract

Purpose: In this study, it is aimed to compare the serum leptin and PAI-1 levels and evaluate their relationship in children on hemodialysis (HD) and peritoneal dialysis (PD). Method: Thirty-six patients on HD (mean age: 15.0?±?2.8 years), 19 patients on PD (mean age: 13.0?±?3.5 years) and 15 healthy subjects (mean age: 14.5?±?2.7 years) were included in the study. Laboratory investigations included blood count, biochemical parameters, serum iron, iron binding capacity, parathormone, erythrocyte sedimentation rate, C-reactive protein (CRP), prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen, serum leptin and PAI-1 levels. Results: Serum leptin levels were significantly higher in HD group than in control group when the effects of BMI and sex were controlled, while PD and control groups had similar leptin levels. PAI-1 levels were also significantly higher in HD group than in control group, while there was no statistically significant difference in PAI-1 levels of PD and control group. PAI-1 levels and leptin levels were significantly correlated, which was independent of the effect of BMI in both HD and PD groups when they are evaluated separately. Conclusion: Results of our study showed that HD patients had higher leptin and PAI-1 levels and leptin and PAI-1 levels were correlated significantly in both patient groups. The effect of elevated serum leptin and PAI-1 levels on the cardiovascular complications remains to be established.     

尿激酶在雄性生殖中的作用

尿激酶型纤溶酶原激活因子(uPA)存在于许多动物的生殖系统,在雄性生殖系统精子和精浆中都可以检测到。关于uPA的作用机制尚未完全阐明,目前多数学者认为uPA是通过与uPA受体结合而发挥作用。在雄性生殖系统,uPA的生理作用是多方面的,它参与精子发生、成熟、运动、获能、顶体反应、受精以及精液液化等生殖生理过程。现就uPA在此方面的研究进展作一综述。     

Initiation of a fibrinolytic system in hepatic resection: The roles of tissue-type plasminogen activator and plasminogen activator inhibitor-1

The factors related to the initiation of fibrinolysis, especially with regard to the tissue-type plasminogen activator (tPA) and the plasminogen activator inhibitor-1 (PAI-1), were investigated in 15 patients who underwent hepatic resection, and the findings were compared between those with normal livers and those with diseased livers. It was found that tPA increased before hepatic division, whereas PAI-1 increased after hepatic division and reached a peak immediately following the operation. Plasminogen decreased during hepatectomy, reaching its lowest point on postoperative day 1, and increasing later. Decreased levels of both plasminogen and the ₂-plasmin inhibitor were considered to be partly due to plasmin formation in the blood. Patients with a diseased liver tended to have higher intraoperative values of euglobulin lysis activity and higher postoperative values of plasminogen activator, but significantly lower postoperative values of ₂-plasmin inhibitor than those with a normal liver. The results of this study suggest that activation of the fibrinolytic system occurs both during hepatectomy and in the early postoperative period, and that patients with a diseased liver are prone to develop hyperfibrinolysis during hepatectomy. Moreover, the increased levels of both tPA and PAI-1 can serve as one of the most sensitive markers for the vital reaction against surgical stress.     

骨肉瘤中尿激酶型纤溶酶原激活因子和受体的表达

目的研究尿激酶型纤溶酶原激活因子(uPA)及其受体(uPAR)在不同外科分期骨肉瘤中的表达及意义.方法采用荧光定量RT-PCR方法检测32例骨肉瘤组织uPA和uPAR表达情况.结果肿瘤组织与癌旁组织和正常组织比较,uPA和uPAR表达的阳性率明显增高(P＜0.01).骨肉瘤Ⅰ、Ⅱ、Ⅲ期表达uPA的阳性率分别为22.2%(2/9)、76.9%(10/13)、90.0%(9/10),表达uPAR的阳性率分别为33.3%(3/9)、84.6%(11/13)、90.0%(9/10).uPA和uPAR在Ⅰ期和Ⅱ期、Ⅰ期和Ⅲ期骨肉瘤中表达差异均有显著性(P＜0.05、P＜0.01).结论uPA/uPAR在骨肉瘤组织中表达明显升高.肿瘤恶性程度越高,uPA/uPAR表达阳性率越高,提示uPA/uPAR与骨肉瘤恶性进展有高度相关性.     

N-Acetyl-seryl-aspartyl-lysyl-proline inhibits TGF-beta-mediated plasminogen activator inhibitor-1 expression via inhibition of Smad pathway in human mesangial cells

Recent large clinical trials indicate that angiotensin-converting enzyme inhibitors (ACE-I) attenuate the detrimental outcome of progressive renal disease. The hemoregulatory tetrapeptide N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP, AcSDKP) is hydrolyzed by ACE, and plasma Ac-SDKP level is increased by fivefold after treatment with ACE-I. Ac-SDKP was found to ameliorate cardiac and renal fibrosis in hypertensive animal models. However, the molecular mechanisms by which Ac-SDKP mediates anti-fibrotic effects remain unclear. This study is an examination of the interaction between Ac-SDKP and transforming growth factor-beta (TGF-beta), one of the key cytokines in the progression of renal disease, in human mesangial cells. Ac-SDKP inhibited TGF-beta1-induced plasminogen activator inhibitor-1 (PAI-1) and alpha2 (I) collagen mRNA. Ac-SDKP suppressed not only TGF-beta1-induced Smad2 phosphorylation at Ser-465/467 in a dose-dependent manner, but also the nuclear accumulation of receptor-regulated Smads (R-Smad), Smad2 and Smad3. As expected, Ac-SDKP inhibited TGF-beta-responsive Smad-dependent luciferase reporters, 3TP-luc and 4xSBE-luc. Immunofluorescence analysis revealed that the inhibitory Smad, Smad7, was exported to the cytoplasm from the nucleus by the treatment with Ac-SDKP. These findings provide novel evidence that Ac-SDKP inhibits TGF-beta signal transduction through the suppression of R-Smad activation via nuclear export of Smad7, highlighting an alternative mechanism involved in the reno-protective efficacy of ACE-I.     

Effect of dextran on plasma tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1(PAI-1) during surgery

Dextran is known to increase the plasminogen activation rate in vitro and to decrease the α₂-antiplasmin activity.
We decided to explore the effect of dextran on plasma tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1(PAI-1) during surgical trauma.
Thirty-one patients undergoing elective surgery were given 500 ml of 6% dextran 70. Another nine patients serving as controls were given 500 ml of a glucose-electrolyte solution. The activities of t-PA and PAI-1during surgery were determined, as was the concentration of t-PA antigen.
PAI-1activity was decreased by 19% after infusion of 250 ml of dextran. After 500 ml, the activity was reduced by 22% (both P <0.05). The activity of t-PA was increased by 43% and 29% (both P <0.05) and the antigenic amount of t-PA was increased by 18% and 15% (both P <0.05) after infusion of 250 ml and 500 ml of dextran, respectively. No changes in these variables were observed in the control patients.
It is concluded that infusion of dextran promotes fibrinolysis by enhancing plasminogen activation in patients subjected to trauma. Since elevated levels of PAI-1prior to surgery are known to predispose to deep vein thrombosis, which may form already during the operation, the effect of dextran on PAI-1described here may explain its clot preventing properties.