白介素-1β诱导人脐静脉内皮细胞表达纤溶酶原激活物抑制剂-1的实验研究

探讨白介素-1β(IL-1β)在诱导人脐静脉内皮细胞表达纤溶酶原激活物抑制剂-1(PAI-1)中的作用及机制.方法:培养原代人脐静脉内皮细胞,四甲基偶氮唑盐微量酶反应比色法监测不同浓度IL-1β刺激下的细胞活性;Real Time PCR及蛋白质印迹检测不同时间及不同浓度的IL-1β对PAI-1基因及蛋白表达的影响;进一步用核转录因子-KB(NF-κB)拮抗剂PDTC(5 mol/L)探讨信号传导机制,检测IL-1β对PAI-1的诱导情况.结果:MTT结果示IL-1β在0～10 ng/mL浓度下,细胞的活性不受影响(P＞0.05),20 ng/mL IL-1β刺激下细胞活性改变(P＜0.05),差异有统计学意义;不同浓度IL-1β刺激下人脐静脉内皮细胞内PAI-1基因及蛋白的表达成时间依赖性,6h后开始增高(P＜0.05),12h后达峰值(P＜0.01),24 h后开始下降(P＜0.05),差异有统计学意义;IL-1β对PAI-1的刺激作用亦呈剂量依赖性,随着浓度(0、0.1、1、10 ng/mL)的增加,PAI-1基因及蛋白的表达亦明显增加(P＜0.05),差异有统计学意义;进一步的信号通路研究实验结果显示NF-κB拮抗剂PDTC可抑制IL-1β的诱导作用(P＜0.05).结论:在人脐静脉内皮细胞中,IL-1β可通过NF-κB信号途径上调PAI-1的表达,PDTC可抑制其上调作用.     

缬沙坦对肾小球硬化大鼠纤溶酶原激活物抑制物-1表达影响

目的:探讨缬沙坦对大鼠肾小球硬化细胞外基质降解系统的影响.方法:30只雄性SD大鼠随机分为A,B,C 3组.对B,C 2组大鼠行左肾切除,1周后经尾静脉注射阿霉素,建立肾小球硬化模型.A组行假手术及尾静脉注射等量生理盐水为正常对照.C组给予缬沙坦20 mg/kg,灌胃1次/d;A,B 2组给予2 mL清水灌胃,1次/d.12周后处死大鼠.观察各组大鼠24 h尿蛋白含量及血生化指标和肾脏病理改变,用免疫组织化学方法检测肾脏组织中Ⅳ型胶原、纤溶酶原激活物抑制物-1蛋白表达;用原位杂交方法检测肾脏组织纤溶酶原激活物抑制物-1 mRNA的表达.结果:第6周C组尿蛋白较B组明显降低(P<0.05),第12周血白蛋白较B组明显增高(P<0.05);B组多数肾小球呈节段性硬化,C组肾小球硬化指数明显低于B组(P<0.01);C组Ⅳ型胶原、纤溶酶原激活物抑制物-1在肾脏沉积较B组明显减少(P<0.05);纤溶酶原激活物抑制物-l mRNA表达量明显增加(P<0.05).纤溶酶原激活物抑制物-1及纤溶酶原激活物抑制物-1 mRNA吸光光度值与Ⅳ型胶原均呈正相关.结论:缬沙坦通过降低纤溶酶原激活物抑制物-1在肾脏表达,促进细胞外基质降解而延缓肾小球硬化的进展.     

Pleiotropic functions of plasminogen activator inhibitor-1

Plasminogen activator inhibitor-1 (PAI-1), a 45-kDa serine proteinase inhibitor with reactive site peptide bond Arg345-Met346, is the main physiological plasminogen activator inhibitor. It occurs in human plasma at an antigen concentration of about 20 ng mL(-1). Besides the active inhibitory form of PAI-1 that spontaneously converts to a latent form, also a substrate form exists that is cleaved at the P1-P1' site by its target enzymes, but does not form stable complexes. Besides its role in regulating hemostasis, PAI-1 plays a role in several biological processes dependent on plasminogen activator or plasmin activity. Studies with transgenic mice have revealed a functional role for PAI-1 in wound healing, atherosclerosis, metabolic disturbances such as obesity and insulin resistance, tumor angiogenesis, chronic stress, bone remodeling, asthma, rheumatoid arthritis, fibrosis, glomerulonephritis and sepsis. It is not always clear if these functions depend on the antiproteolytic activity of PAI-1, on its binding to vitronectin or on its intereference with cellular migration or matrix binding.     

螺内酯对醛固酮刺激下大鼠肾小球系膜细胞PAI-1表达的影响

目的探讨醛固酮对体外培养大鼠肾小球系膜细胞纤溶酶原激活物抑制物－1（PAl-1）表达的影响及螺内酯的干预作用。方法体外培养大鼠肾小球系膜细胞,设正常对照组、醛固酮（10-7mol·L-1）组、不同浓度螺内酯（10-7,10-8,10-9mol·L-1）干预组,48h后收集细胞及上清液,以RT-PCR检测PM-1、醛固酮受体（MR）和保护其配体特异性的11p羟类固醇脱氢酶2（11β-HSD2）的mRNA表达,采用ELISA检测培养细胞上清中PAI-1蛋白的浓度。结果RT-PCR结果,肾小球系膜细胞表达MR和118．HSD2mRNA,醛固酮可显著上调肾小球系膜细胞PM-1mRNA表达,螺内酯可抑制醛固酮诱导的PA／-1mRNA表达,且呈剂量依赖性;ELISA结果示醛固酮组上清液中PAI-1水平明显增加,螺内酯干预组PAI-1水平明显降低并与浓度有关。结论螺内酯与醛固酮竞争结合MR,抑制醛固酮刺激的大鼠。肾小球系膜细胞中PAI-1mRNA的表达和蛋白合成。     

过氧化物酶体增殖物激活型受体α不同激活物对HepG2细胞1型纤溶酶原激活物抑制剂表达的影响

目的：观察不同的过氧化物酶体增殖物激活型受体α对人肝瘤细胞1型纤溶酶原激活物抑制剂mRNA表达及其活性的影响,探讨过氧化物酶体增殖物激活型受体α在1型纤溶酶原激活物抑制剂基因调控中的作用.方法：实验于2004-04/2005-04在军事医学科学院放射医学研究所药理毒理实验室完成.分别以终浓度为50和100 μmol/L的过氧化物酶体增殖物激活型受体α不同特异性激活物非诺贝特和亚油酸作用于人肝瘤细胞,设未加入非诺贝特和亚油酸作用于人肝瘤细胞为空白对照组.采用半定量反转录-聚合酶链式反应法检测人肝瘤细胞1型纤溶酶原激活物抑制剂及过氧化物酶体增殖物激活型受体α的mRNA水平,发色底物法检测1型纤溶酶原激活物抑制剂的活性变化.结果：[1]与空白对照组相比,非诺贝特组在50和100 μmol/L浓度诱导下1型纤溶酶原激活物抑制剂mRNA表达分别减少31.97%,45.49%（P＜0.05,0.01）;亚油酸组在50和100 μmol/L浓度诱导下1型纤溶酶原激活物抑制剂mRNA表达分别增加43.0%,129.0%（P＜0.05,0.01）.[2]与空白对照组相比,非诺贝特组在50和100 μmol/L浓度诱导下1型纤溶酶原激活物抑制剂蛋白活性分别降低39.3%,49.6%（P＜0.01）;亚油酸组在50和100 μmol/L浓度诱导下1型纤溶酶原激活物抑制剂蛋白活性分别升高37.5%,112.6%（P＜0.01）.与空白对照组相比,人肝瘤细胞过氧化物酶体增殖物激活型受体αmRNA表达量在非诺贝特组100 μmol/L浓度诱导下明显增高79.79%（P＜0.05）,在亚油酸组50和100 μmol/L浓度诱导下则分别显著增高46.73%（P＜0.05）,79.45%（P＜0.01）,非诺贝特组50 μmol/L浓度诱导下使人肝瘤细胞过氧化物酶体增殖物激活型受体αmRNA表达量有升高趋势,但差异不明显.结论：过氧化物酶体增殖物激活型受体α激活物可以影响人肝瘤细胞1型纤溶酶原激活物抑制剂的基因转录及过氧化物酶体增殖物激活型受体αmRNA的表达,且均呈一定剂量依赖性,但非诺贝特和亚油酸对1型纤溶酶原激活物抑制剂的作用迥然不同.     

过氧化物酶体增殖物激活型受体α不同激活物对HepG2细胞1型纤溶酶原激活物抑制剂表达的影响

目的观察不同的过氧化物酶体增殖物激活型受体α对人肝瘤细胞1型纤溶酶原激活物抑制剂mRNA表达及其活性的影响,探讨过氧化物酶体增殖物激活型受体α在1型纤溶酶原激活物抑制剂基因调控中的作用.方法实验于2004-04/2005-04在军事医学科学院放射医学研究所药理毒理实验室完成.分别以终浓度为50和100 μmol/L的过氧化物酶体增殖物激活型受体α不同特异性激活物非诺贝特和亚油酸作用于人肝瘤细胞,设未加入非诺贝特和亚油酸作用于人肝瘤细胞为空白对照组.采用半定量反转录-聚合酶链式反应法检测人肝瘤细胞1型纤溶酶原激活物抑制剂及过氧化物酶体增殖物激活型受体α的mRNA水平,发色底物法检测1型纤溶酶原激活物抑制剂的活性变化.结果[1]与空白对照组相比,非诺贝特组在50和100 μmol/L浓度诱导下1型纤溶酶原激活物抑制剂mRNA表达分别减少31.97%,45.49%(P＜0.05,0.01);亚油酸组在50和100 μmol/L浓度诱导下1型纤溶酶原激活物抑制剂mRNA表达分别增加43.0%,129.0%(P＜0.05,0.01).[2]与空白对照组相比,非诺贝特组在50和100 μmol/L浓度诱导下1型纤溶酶原激活物抑制剂蛋白活性分别降低39.3%,49.6%(P＜0.01);亚油酸组在50和100 μmol/L浓度诱导下1型纤溶酶原激活物抑制剂蛋白活性分别升高37.5%,112.6%(P＜0.01).与空白对照组相比,人肝瘤细胞过氧化物酶体增殖物激活型受体αmRNA表达量在非诺贝特组100 μmol/L浓度诱导下明显增高79.79%(P＜0.05),在亚油酸组50和100 μmol/L浓度诱导下则分别显著增高46.73%(P＜0.05),79.45%(P＜0.01),非诺贝特组50 μmol/L浓度诱导下使人肝瘤细胞过氧化物酶体增殖物激活型受体αmRNA表达量有升高趋势,但差异不明显.结论过氧化物酶体增殖物激活型受体α激活物可以影响人肝瘤细胞1型纤溶酶原激活物抑制剂的基因转录及过氧化物酶体增殖物激活型受体αmRNA的表达,且均呈一定剂量依赖性,但非诺贝特和亚油酸对1型纤溶酶原激活物抑制剂的作用迥然不同.     

Adrenal gland-dependent augmentation of plasminogen activator inhibitor-1 expression in streptozotocin-induced diabetic mice

BACKGROUND: Diabetes is associated with an excess risk of cardiac events, and one risk factor for infarction is an elevated level of plasminogen activator inhibitor-1 (PAI-1). OBJECTIVES AND METHODS: To evaluate whether the glucocorticoid hormones are involved in the diabetes-induced PAI-1 production, we examined expression profiles of PAI-1 mRNA in adrenalectomized (ADX) mice with streptozotocin (STZ)-induced diabetes. RESULTS: The diabetes-induced augmentation of plasma PAI-1 levels and PAI-1 mRNA expression in the heart and lungs was completely normalized in diabetic ADX mice. The glucocorticoid receptor antagonist RU486 significantly, but only partly suppressed PAI-1 induction in STZ-induced diabetic mice, suggesting that factors other than glucocorticoids are also involved in PAI-1 induction provoked by diabetes. CONCLUSION: Our results suggested that the adrenal gland plays a critical role in the progression of thrombosis in diabetic patients by inducing expression of the PAI-1 gene.     

Atorvastatin reduces plasminogen activator inhibitor-1 expression in adipose tissue of atherosclerotic rabbits

Considerable attention has been focused on definition and enhancement of the analytical quality in laboratory testing over the past decades. Advances in laboratory technology and computer informatics have allowed a major sense of confidence with the analytical phase and more efforts should now be focused on extra-analytical areas of improvement, that should further strengthen the link between cost effectiveness and clinical outcome. Deduction and implementation of common reference intervals, to be possibly shared by a regional network of clinical laboratories, appear so far a crucial step to increase efficiency and harmonization. With the experience gained from External Quality Control exercises and with the consensus of several contributory laboratories, this process is underway in Italy. Quality performances resulting from widespread implementation of common reference intervals and longitudinal comparison of patient's data, will allow clinical laboratories to accomplish with a major transferability, amplifying health benefits and meeting increasing health systems demand.     

四种烤瓷冠基底金属浸提液干预人牙龈成纤维细胞尿纤溶酶原激活剂和Ⅰ型纤溶酶原激活物抑制剂的表达

背景:修复材料的生物相容性是决定临床修复效果的重要因素之一。目的:通过比较4种金属浸提液对人牙龈成纤维细胞尿纤溶酶原激活剂和Ⅰ型纤溶酶原激活物抑制剂表达的差异探索其生物相容性。方法:选用活体牙龈,原代培养人牙龈成纤维细胞,采用镍铬、钴铬、纯钛及金钯合金4种金属浸提液进行干预,以未进行干预的细胞作为对照。结果与结论:ELISA检测结果显示镍铬和钴铬合金浸提液干预后细胞尿纤溶酶原激活剂表达增加;免疫荧光实验结合电镜观察发现镍铬和钴铬合金浸提液干预的细胞胞质荧光染色深,分布均匀,遍布整个细胞,提示细胞Ⅰ型纤溶酶原激活物抑制剂表达增加。而纯钛和金钯合金浸提液对细胞尿纤溶酶原激活剂和Ⅰ型纤溶酶原激活物抑制剂的表达无影响。说明纯钛和金钯合金的生物相容性优于镍铬和钴铬合金。     

Disruption of plasminogen activator inhibitor-1 gene enhances spontaneous enlargement of mouse airspace with increasing age

Plasminogen activator inhibitor-1 (PAI-1) is the most effective protease inhibitor in the fibrinolysis system, and plays an important role in the remodeling of the extracellular matrix. We therefore explored whether PAI-1 is involved in the change of lung structure with increasing age. PAI-1 gene knockout mice and wild-type mice were sacrificed at age 3 weeks, 3 months, 6 months and 15 months for histopathology analysis, and assessed the relationship between PAI-1 and the change in lung structure with age. Six-month-old mice were chosen for further studies. Elastin in the lung was detected using Weigert staining. We measured the expression of matrix metalloproteinase-12 (MMP-12) that is a major protease in elastin degradation by real time PCR and immunostaining. Transforming growth factor-β1 (TGF-β1) expression was measured by western blot analysis. PAI-1 gene knockout mice showed significant increases in alveolar size with increasing age and damaged alveolar structure at the age of 15 months, compared with wild-type mice. At the age of 6 months, elastin protein was decreased in the lungs of PAI-1 gene knockout mice. PAI-1 null mice had higher MMP-12 mRNA expression, and lower expression level of active TGF-β1 in the lung. Taken together, these results indicate that the emphysema-like change attributed to PAI-1 deficiency might be facilitated with increased MMP-12 expression that accelerates elastin degradation in mice lungs, and TGF-β1 might be involved in the modulation of this process.     

Niacin affects cell adhesion molecules and plasminogen activator inhibitor-1 in HepG2 cells

BACKGROUND: Beyond lipid-modifying actions, niacin lowers the risk of atherothrombotic events by lowering prothrombotic factors like fibrinogen. Plasminogen activator inhibitor type 1 (PAI-1) is a potential factor for atherogenesis and thrombosis, increased in acute myocardial infarctions and restenosis after angioplasty. Cell adhesion molecules (CAM) mediate adhesion, recruitment and migration of white blood cells through vascular surfaces, an essential process in atherogenesis. ICAM-1 is a significant predictor of future coronary events. Whether niacin affects ICAM-1 expression is unknown. We studied the effects of niacin on PAI-1 and CAM using HepG2 cells. METHODS: HepG2 cells were cultured in DMEM until 90% confluent. After serum starvation, cells were exposed to DME/F12 containing niacin. Transforming growth factor-beta (TGF-beta) was added directly to cell media. Cell lysate and conditioned media were collected for measurement of PAI-1 by ELISA. For measurement of ICAM, cells were treated with tumor necrosis factor-alpha (TNF-alpha) instead. The effect of niacin on mRNA expression of ICAM-1 was studied using RT-PCR. RESULTS: Niacin reduced the TGF-beta-induced rise by 30% to 55% (p=0.002). The differences in degree of PAI-1 reduction, between different niacin concentrations, were not statistically significant. Niacin reduced TNF-alpha-induced rise in ICAM-1 levels by 66% to 89% (p<0.0001), but did not significantly affect TNF-alpha-induced rise in PECAM-1. Semiquantitative RT-PCR analysis showed that reduced TNF-alpha-induced rise in ICAM-1 mRNA expression significantly by 17% (p=0.001). CONCLUSIONS: Treatment with niacin suppressed PAI-1 and ICAM-1 levels in HepG2 cells. Further studies to understand the mechanistic pathways of this suppression, could further explain benefits of niacin in prevention of atherosclerotic disease, and offer therapeutic avenues against the rising burden of atherothrombotic disease.     

大鼠局灶性脑缺血再灌注损伤过程中组织型纤溶酶原激活物及其抑制物的表达变化

目的:观察大鼠局灶性脑缺血再灌注损伤过程中组织型纤溶酶原激活物及其抑制物表达变化规律,探讨纤溶系统在脑缺血再灌注损伤中的作用。方法:实验于2001/2003在吉林大学第一临床学院神经内科进行。取雄性Wistar大鼠48只,随机分成正常对照组(n=6)、假手术组(n=6)及实验组(n=36),实验组又分为缺血90min再灌注0,6,12,24,48,72h组,每组6只。正常对照组不干预;实验组采用线栓法制备局灶性脑缺血模型,假手术组尼龙线未进入大脑中动脉。各组均于缺血90min后拔除线栓,实验组于再灌注不同时间点断头取脑。应用免疫组织化学及原位杂交方法检测缺血再灌注不同时间点组织型纤溶酶原激活物及其抑制物表达变化,同时应用脱氧尿嘧啶缺口末端标记法观察神经元凋亡变化。结果:48只动物均进入结果分析。①正常大鼠大脑皮质及尾壳核神经元可见组织型纤溶酶原激活物及其抑制物蛋白、mRNA的弱表达。②脑缺血再灌注不同时间点,二者表达呈不同的动态变化:组织型纤溶酶原激活物蛋白、mRNA在再灌注0h即开始表达,主要见于形态结构正常的神经元;于再灌注48h表达明显增强,持续至再灌注72h,于皮质、尾壳核损伤中心区坏死残存的神经元表达最为明显,于损伤中心区周边的部分固缩神经元及正常的神经元表达也增强。组织型纤溶酶原激活物抑制物蛋白、mRNA开始表达迟于前者,于再灌注72h最为明显,其表达部位与组织型纤溶酶原激活物相同,但表达强度较弱。③脱氧尿嘧啶缺口末端标记法染色显示,再灌注早期在缺血区的大脑皮质及尾壳核外侧部可见少量散在凋亡神经元,随再灌注时间延长凋亡细胞数目增多,于再灌注48～72h达高峰。结论:组织型纤溶酶原激活物参与了脑缺血再灌注性损伤,并可能是通过启动神经元凋亡过程所致;其抑制物延迟表达可能是组织型纤溶酶原激活物表达阶梯状升高后反应所致。     

Gender-specific correlations of plasminogen activator inhibitor-1 and tissue plasminogen activator levels with cardiovascular disease-related traits

Summary.  Background:  The purpose of this study was to examine the correlations between plasma levels of plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (t-PA) and cardiovascular disease-related traits in a general population and whether these correlations differed between females and males. Methods:  Plasma PAI-1 and t-PA antigen levels and C-reactive protein (CRP), HDL-cholesterol, triglycerides, total cholesterol, systolic blood pressure, diastolic blood pressure, urinary albumin excretion, and glucose were measured in the population-based PREVEND study in Groningen, the Netherlands ( n  = 2527). Results:  Except for CRP and total cholesterol levels, all traits were significantly different between gender ( P  < 0.001). PAI-1 levels were correlated with all measured cardiovascular disease-related traits ( P  < 0.01) in both females and males. Except for urinary albumin excretion, similar results, albeit less significant, were found for t-PA levels. Age-adjusted correlations between PAI-1 and CRP, triglycerides, total cholesterol, systolic blood pressure, and diastolic blood pressure differed significantly between females and males ( P  < 0.01). Many of the gender differences were predominantly present between premenopausal females and males. Conclusion:  PAI-1 and t-PA levels were correlated with cardiovascular disease-related traits in subjects obtained from the general population and several of these correlations differed across gender. The correlations found in the present study suggest the presence of coordinated patterns of cardiovascular risk factors and indicate which traits might influence PAI-1 and t-PA levels and thereby provide a framework and potential tool for therapeutic intervention to reduce thromboembolic events in the general population.     

Angiotensin II induces plasminogen activator inhibitor-1 and -2 expression in vascular endothelial and smooth muscle cells.

Angiotensin II (AII)- and Arg8-vasopressin (AVP)-regulated gene expression in vascular cells has been reported to contribute to vascular homeostasis and hypertrophy. In this report, AVP-induced expression of plasminogen activator inhibitor (PAI)-2 mRNA in rat microvessel endothelial (RME) cells was identified using differential mRNA display. Further characterization of vasoactive peptide effects on PAI expression revealed that AII stimulated a 44.8 +/- 25.2-fold and a 12.4 +/- 3.2-fold increase in PAI-2 mRNA in RME cells and rat aortic smooth muscle cells (RASMC), respectively. AII also stimulated a 10- and 48-fold increase in PAI-1 mRNA in RME cells and RASMC, respectively. These AII effects were inhibited by either Sar1, Ile8-angiotensin or the AT1 antagonist DuP 735, but were not significantly altered in the presence of the AT2 antagonist PD123319. AII stimulation of RASMC and RME cells also significantly increased both PAI-1 protein and PAI activity released to the culture medium. Inhibition of protein kinase C completely blocked PMA-stimulated induction of PAI-2 mRNA in both cell types and inhibited the AII-stimulated increase in RASMC by 98.6 +/- 2.8%. In contrast, protein kinase C inhibition only partially decreased the AII-stimulated PAI-2 expression in RME cells by 68.8 +/- 11.1%, suggesting that a protein kinase C-independent mechanism contributes to a 6.9 +/- 1.5-fold AII induction of PAI-2 expression in endothelial cells. AII and PMA also stimulated protein tyrosine phosphorylation in RME cells, and the tyrosine kinase inhibitor genistein partially blocked their induction of PAI-2 mRNA. These findings suggest that AII may regulate plasminogen activation in the vasculature by inducing both PAI-1 and PAI-2 expression.     

PAI-1蛋白在子宫内膜异位症组织的表达及意义

目的：探讨PAI-1蛋白在异位内膜、在位内膜厦对照组内膜的表达及意义。方法：应用免疫组化方法检测PAI-1蛋白在40例内异症组异位内膜及在位内膜，30例对照组子宫内膜的表达。结果：①PAI-1蛋白表达于异位内膜、在位内膜、对照组内膜的腺上皮细胞及间质细胞胞浆；②PAI-1蛋白在异位内膜厦对照组内膜间质细胞表达均高于腺上皮细胞（P〈0．05），而于在位内膜腺上皮细胞与间质细胞表达比较无统计学意义（P〉0．05）；③PAI-1蛋白在间质细胞表达异位内膜高于在位内膜及对照组内膜（P〈0．05），而在腺上皮细胞表达异住内膜、在位内膜、对照组内膜三者之间比较无统计学意义（P〉0．05）；④PAI-1蛋白在血管内皮细胞呈阳性表达。结论：PAI-1蛋白在异位内膜间质细胞高表达可能促使其转移、黏附、侵袭、生长，导致子宫内膜异住症的发生发展。     

Reactive site-dependent phenotypic alterations in plasminogen activator inhibitor-1 transgenic mice

BACKGROUND: Plasminogen activator inhibitor-1 (PAI-1) is the major physiological inhibitor of plasminogen activators (PAs) and plays a role in the regulation of a number of physiological processes including the degradation of extracellular matrix proteins, cell proliferation and migration, and intracellular signaling. AIM: To characterize the effects of durable expression of a stable form of human PAI-1 and to characterize important structure-function relationships in PAI-1 in vivo. METHODS: We developed transgenic mice lines overexpressing stable variants of human PAI-1 under the control of the murine preproendothelin-1 promoter and characterized the phenotypic alterations displayed by transgenic mice. RESULTS: Transgenic mice expressing an active form of human PAI-1 (PAI-1-stab) display complex phenotypic abnormalities including alopecia and hepatosplenomegaly. Reactive site mutant transgenic mice expressing inactive PAI-1 exhibit complete phenotypic rescue, while transgenic mice expressing PAI-1 with reduced affinity for vitronectin manifest all of the phenotypic abnormalities present in PAI-1-stab transgenic mice. CONCLUSIONS: The protease inhibitory activity of PAI-1 toward PAs and/or other serine proteases is necessary and sufficient to promote complex phenotypic abnormalities and mediates many of the physiological effects of PAI-1 in vivo.