共查询到20条相似文献,搜索用时 9 毫秒
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Shuang Zhou Zhu‐Qin Zhang De‐Long Hao Li‐Shan Lian Yong‐Jun Li Hou‐Zao Chen De‐Pei Liu 《Aging cell》2014,13(5):890-899
The inactivation of plasminogen activator inhibitor‐1 (PAI‐1) has been shown to exert beneficial effects in age‐related vascular diseases. Limited information is available on the molecular mechanisms regarding the negatively regulated expression of PAI‐1 in the vascular system. In this study, we observed an inverse correlation between SIRT1, a class III histone deacetylase, and PAI‐1 expression in human atherosclerotic plaques and the aortas of old mice, suggesting that internal negative regulation exists between SIRT1 and PAI‐1. SIRT1 overexpression reversed the increased PAI‐1 expression in senescent human umbilical vein endothelial cells (HUVECs) and aortas of old mice, accompanied by decreased SA‐β‐gal activity in vitro and improved endothelial function and reduced arterial stiffness in vivo. Moreover, the SIRT1‐mediated inhibition of PAI‐1 expression exerted an antisenescence effect in HUVECs. Furthermore, we demonstrated that SIRT1 is able to bind to the PAI‐1 promoter, resulting in a decrease in the acetylation of histone H4 lysine 16 (H4K16) on the PAI‐1 promoter region. Thus, our findings suggest that the SIRT1‐mediated epigenetic inhibition of PAI‐1 expression exerts a protective effect in vascular endothelial senescence. 相似文献
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Thompson LC Goswami S Peterson CB 《Protein science : a publication of the Protein Society》2011,20(2):366-378
Human plasminogen activator inhibitor type 1 (PAI-1) is a serine protease inhibitor with a metastable active conformation. The lifespan of the active form of PAI-1 is modulated via interaction with the plasma protein, vitronectin, and various metal ions. These metal ions fall into two categories: Type I metals, including calcium, magnesium, and manganese, stabilize PAI-1 in the absence of vitronectin, whereas Type II metals, including cobalt, copper, and nickel, destabilize PAI-1 in the absence of vitronectin, but stabilize PAI-1 in its presence. To provide a mechanistic basis for understanding the unusual modulation of PAI-1 structure and activity, the binding characteristics and conformational effects of these two types of metals were further evaluated. Steady-state binding measurements using surface plasmon resonance indicated that both active and latent PAI-1 exhibit a dissociation constant in the low micromolar range for binding to immobilized nickel. Stopped-flow measurements of approach-to-equilibrium changes in intrinsic protein fluorescence indicated that the Type I and Type II metals bind in different modes that induce distinct conformational effects on PAI-1. Changes in the observed rate constants with varying concentrations of metal allowed accurate determination of binding affinities for cobalt, nickel, and copper, yielding dissociation constants of ~40, 30, and 0.09 μM, respectively. Competition experiments that tested effects on PAI-1 stability were consistent with these measurements of affinity and indicate that copper binds tightly to PAI-1. 相似文献
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Thompson LC Goswami S Ginsberg DS Day DE Verhamme IM Peterson CB 《Protein science : a publication of the Protein Society》2011,20(2):353-365
Human plasminogen activator inhibitor type 1 (PAI-1) is a serine protease inhibitor with a metastable active conformation. Under physiological conditions, half of the inhibitor transitions to a latent state within 1-2 h. The interaction between PAI-1 and the plasma protein vitronectin prolongs this active lifespan by ~50%. Previously, our group demonstrated that PAI-1 binds to resins using immobilized metal affinity chromatography (Day, U.S. Pat. 7,015,021 B2, March 21, 2006). In this study, the effect of these metals on function and stability was investigated by measuring the rate of the transition from the active to latent conformation. All metals tested showed effects on stability, with the majority falling into one of two types depending on their effects. The first type of metal, which includes magnesium, calcium and manganese, invoked a slight stabilization of the active conformation of PAI-1. A second category of metals, including cobalt, nickel and copper, showed the opposite effects and a unique vitronectin-dependent modulation of PAI-1 stability. This second group of metals significantly destabilized PAI-1, although the addition of vitronectin in conjunction with these metals resulted in a marked stabilization and slower conversion to the latent conformation. In the presence of copper and vitronectin, the half-life of active PAI-1 was extended to 3 h, compared to a half-life of only ~30 min with copper alone. Nickel had the largest effect, reducing the half-life to ~5 min. Together, these data demonstrate a heretofore-unknown role for metals in modulating PAI-1 stability. 相似文献
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Single fluorescence probes along the reactive center loop reveal site‐specific changes during the latency transition of PAI‐1
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Tihami Qureshi Cynthia B. Peterson 《Protein science : a publication of the Protein Society》2016,25(2):487-498
The serine protease inhibitor (serpin), plasminogen activator inhibitor‐1 (PAI‐1), is an important biomarker for cardiovascular disease and many cancers. It is therefore a desirable target for pharmaceutical intervention. However, to date, no PAI‐1 inhibitor has successfully reached clinical trial, indicating the necessity to learn more about the mechanics of the serpin. Although its kinetics of inhibition have been extensively studied, less is known about the latency transition of PAI‐1, in which the solvent‐exposed reactive center loop (RCL) inserts into its central β‐sheet, rendering the inhibitor inactive. This spontaneous transition is concomitant with a large translocation of the RCL, but no change in covalent structure. Here, we conjugated the fluorescent probe, NBD, to single positions along the RCL (P13‐P5′) to detect changes in solvent exposure that occur during the latency transition. The results support a mousetrap‐like RCL‐insertion that occurs with a half‐life of 1–2 h in accordance with previous reports. Importantly, this study exposes unique transitions during latency that occur with a half‐life of ~5 and 25 min at the P5′ and P8 RCL positions, respectively. We hypothesize that the process detected at P5′ represents s1C detachment, while that at P8 results from a steric barrier to RCL insertion. Together, these findings provide new insights by characterizing multiple steps in the latency transition. 相似文献
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Florian Schrötzlmair Charlotte Kopitz Birgit Halbgewachs Fei Lu Hana Algül Nils Brünner Bernd Gänsbacher Achim Krüger 《Journal of cellular and molecular medicine》2010,14(12):2760-2770
Paradoxically, not only proteinases but also their inhibitors can correlate with bad prognosis of cancer patients, underlining the evolving concept of the protease web as the complex interplay between proteinases, their inhibitors and effector molecules. Elevated levels of tissue inhibitor of metalloproteinases‐1 (TIMP‐1) render the liver more susceptible to metastasis by triggering urokinase plasminogen activator (uPA) expression as well as hepatocyte growth factor (HGF) signalling, thereby leading to the fatal scattered infiltration of metastasizing tumour cells throughout the parenchyma of the target organ. Here, we investigated whether host uPA is a crucial protagonist for the TIMP‐1‐induced modulation of a pro‐metastatic microenvironment in the liver. Indeed, in livers of uPA‐ablated mice elevated TIMP‐1 levels did not trigger HGF signalling and did not promote metastasis of a murine T‐lymphoma cell line. In contrast, lack of tumour cell‐derived uPA induced by gene silencing did not interfere with this pro‐metastatic pathway. Furthermore, host uPA was necessary for the recruitment of neutrophilic granulocytes and the associated increase of HGF in livers with elevated TIMP‐1 levels. This newly identified co‐operation between TIMP‐1 and host uPA suggests that therapies, simultaneously interfering with pro‐ and anti‐proteolytic pathways may be beneficial for patients with metastatic disease. 相似文献
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Andrea Hidalgo Lizbeth Salazar‐Sanchez Mayra Cartin Max Mendez Jorge Arauz Alexander Parajeles 《Cell biochemistry and function》2010,28(5):367-373
Thrombotic disease is a multifactorial condition that involves both classical and genetic risk factors. We studied the association between the classical risk factors of hypertension and smoking, and polymorphisms on the genes of the angiotensin‐converting enzyme (ACE), the β‐chain of fibrinogen (FG), and the plasminogen activator inhibitor‐1 (PAI‐1) in patients with venous and arterial thrombosis. The present investigation is a retrospective case–control study. A total of 340 participants were analyzed, including 162 patients and 178 healthy controls. Hypertension and smoking showed a significant association with thrombotic disease (p < 0.05) but FG level was found significant risk factor only for the venous thrombosis (VT) group (p < 0.04). Significant differences between thrombotic groups were found for the studied polymorphisms of PAI‐1 (p < 0.0014), but for both FG β‐chain gene polymorphisms, none of the molecular analyses showed a positive sample for any mutating allele (p > 0.05). For the ACE polymorphism, the I allele present a protective effect in the general thrombotic group. This is one of the first reports in a Latin‐American population dealing with these molecular markers and thrombotic diseases. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Kanak L. Dikshit 《Protein science : a publication of the Protein Society》2014,23(6):714-722
Bacterial plasminogen activators differ from each other in their mechanism of plasminogen activation besides their host specificity. Three‐domain streptokinase (SK) and two‐domain PauA generate nonproteolytic active site center in their cognate partner plasminogen but their binary activator complexes are resistant to α2‐antiplasmin (a2AP) inhibition causing nonspecific plasminogen activation in plasma. In contrast, single‐domain plasminogen activator, staphylokinase (SAK), requires proteolytic cleavage of human plasminogen into plasmin for the active site generation, and this activator complex is inhibited by a2AP. The single‐domain plasminogen activator, PadA, from Streptococcus dysgalatiae, having close sequence and possible structure homology with SAK, was recently reported to activate bovine Pg in a nonproteolytic manner similar to SK. We report hereby that the binary activator complex of PadA with bovine plasminogen is inhibited by a2AP and PadA is recycled from this complex to catalyze the activation of plasminogen in the clot environment, where it is completely protected from a2AP inhibition. Catalytic efficiency of the activator complex formed by PadA and bovine plasminogen is amplified several folds in the presence of cyanogen bromide digested fibrinogen but not by intact fibrinogen indicating that PadA may be highly efficient at the fibrin surface. The present study, thus, demonstrates that PadA is a unique single‐domain plasminogen activator that activates bovine plasminogen in a fibrin‐targeted manner like SAK. The sequence optimization by PadA for acquiring the characteristics of both SK and SAK may be exploited for the development of efficient and fibrin‐specific plasminogen activators for thrombolytic therapy. 相似文献
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Plasminogen activator inhibitor type 1 (PAI-1), produced partly from liver is a risk factor for macrovascular and microvascular complications of diabetes. Ghrelin, a recently described orexigenic peptide hormone, attenuates PAI-1 induced by TNF-alpha in the human hepatoma cell line (HepG2). Exposure to TNF-alpha (1 ng/ml) for 24h caused a significant increase in PAI-1 mRNA expression and protein secretion, as evaluated by RT-PCR and ELISA, but pretreatment with ghrelin (1-100 ng/ml) inhibited both basal and TNF-alpha-induced PAI-1 release in a dose and time-dependent manner in HepG2. PDTC, selective NF-kappaB inhibitor, had no additive inhibitory effects with ghrelin. The results indicate that ghrelin inhibits both basal and TNF-alpha-induced PAI-1 production via NF-kappaB pathway in HepG2 cells, and suggest that the peptide plays a therapeutic role in atherosclerosis, especially in obese patients with insulin resistance, in whom ghrelin levels were reduced. 相似文献
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Mi-Hye Lee Samar M. Hammad Andrea J. Semler Louis M. Luttrell Maria F. Lopes-Virella Richard L. Klein 《Journal of lipid research》2010,51(9):2619-2628
Sphingosine-1-phosphate (S1P) is a bioactive lysophospholipid that regulates numerous key cardiovascular functions. High-density lipoproteins (HDLs) are the major plasma lipoprotein carriers of S1P. Fibrinolysis is a physiological process that allows fibrin clot dissolution, and decreased fibrinolytic capacity may result from increased circulating levels of plasminogen activator inhibitor-1 (PAI-1). We examined the effect of S1P associated with HDL subfractions on PAI-1 secretion from 3T3 adipocytes. S1P concentration in HDL3 averaged twice that in HDL2. Incubation of adipocytes with increasing concentrations of S1P in HDL3, but not HDL2, or with S1P complexed to albumin stimulated PAI-I secretion in a concentration-dependent manner. Quantitative RT-PCR revealed that S1P1–3 are expressed in 3T3 adipocytes, with S1P2 expressed in the greatest amount. Treatment of adipocytes with the S1P1 and S1P3 antagonist VPC23019 did not block PAI-1 secretion. Inhibiting S1P2 with JTE-013 or reducing the expression of the gene coding for S1P2 using silencing RNA (siRNA) technology blocked PAI-1 secretion, suggesting that the S1P2 receptor mediates PAI-1 secretion from adipocytes exposed to HDL3 or S1P. Treatment with the phospholipase C (PLC) inhibitor , the protein kinase C (PKC) inhibitor RO-318425, or the Rho-associated protein kinase (ROCK) inhibitor Y27632 all significantly inhibited HDL3- and S1P-mediated PAI-1 release, suggesting that HDL3- and/or S1P-stimulated PAI-1 secretion from 3T3 cells is mediated by activation of multiple, downstream signaling pathways of S1P2. U73122相似文献
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Amr Omer Devang Patel Xian Jin Lian Jason Sadek Sergio Di Marco Arnim Pause Myriam Gorospe Imed Eddine Gallouzi 《EMBO reports》2018,19(5)
Cellular senescence is a physiological response by which an organism halts the proliferation of potentially harmful and damaged cells. However, the accumulation of senescent cells over time can become deleterious leading to diseases and physiological decline. Our data reveal a novel interplay between senescence and the stress response that affects both the progression of senescence and the behavior of senescent cells. We show that constitutive exposure to stress induces the formation of stress granules (SGs) in proliferative and presenescent cells, but not in fully senescent cells. Stress granule assembly alone is sufficient to decrease the number of senescent cells without affecting the expression of bona fide senescence markers. SG‐mediated inhibition of senescence is associated with the recruitment of the plasminogen activator inhibitor‐1 (PAI‐1), a known promoter of senescence, to these entities. PAI‐1 localization to SGs increases the translocation of cyclin D1 to the nucleus, promotes RB phosphorylation, and maintains a proliferative, non‐senescent state. Together, our data indicate that SGs may be targets of intervention to modulate senescence in order to impair or prevent its deleterious effects. 相似文献
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Tihami Qureshi Sumit Goswami Carlee S. McClintock Matthew T. Ramsey Cynthia B. Peterson 《Protein science : a publication of the Protein Society》2016,25(2):499-510
Plasminogen activator inhibitor‐1 (PAI‐1) is a biologically important serine protease inhibitor (serpin) that, when overexpressed, is associated with a high risk for cardiovascular disease and cancer metastasis. Several of its ligands, including vitronectin, tissue‐type and urokinase‐type plasminogen activator (tPA, uPA), affect the fate of PAI‐1. Here, we measured changes in the solvent accessibility and dynamics of an important unresolved functional region, the reactive center loop (RCL), upon binding of these ligands. Binding of the catalytically inactive S195A variant of tPA to the RCL causes an increase in fluorescence, indicating greater solvent protection, at its C‐terminus, while mobility along the loop remains relatively unchanged. In contrast, a fluorescence increase and large decrease in mobility at the N‐terminal RCL is observed upon binding of S195A‐uPA to PAI‐1. At a site distant from the RCL, binding of vitronectin results in a modest decrease in fluorescence at its proximal end without restricting overall loop dynamics. These results provide the new evidence for ligand effects on RCL conformation and dynamics and differences in the Michaelis complex with plasminogen activators that can be used for the development of more specific inhibitors to PAI‐1. This study is also the first to use electron paramagnetic resonance (EPR) spectroscopy to investigate PAI‐1 dynamics. Significance : Balanced blood homeostasis and controlled cell migration requires coordination between serine proteases, serpins, and cofactors. These ligands form noncovalent complexes, which influence the outcome of protease inhibition and associated physiological processes. This study reveals differences in binding via changes in solvent accessibility and dynamics within these complexes that can be exploited to develop more specific drugs in the treatment of diseases associated with unbalanced serpin activity. 相似文献
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Yuzhuo Chu Joel C. Bucci Cynthia B. Peterson 《Protein science : a publication of the Protein Society》2020,29(2):494-508
The serine protease inhibitor, plasminogen activator inhibitor Type‐1 (PAI‐1) is a metastable protein that undergoes an unusual transition to an inactive conformation with a short half‐life of only 1–2 hr. Circulating PAI‐1 is bound to a cofactor vitronectin, which stabilizes PAI‐1 by slowing this latency conversion. A well‐characterized PAI‐1‐binding site on vitronectin is located within the somatomedin B (SMB) domain, corresponding to the first 44 residues of the protein. Another PAI‐1 recognition site has been identified with an engineered form of vitronectin lacking the SMB domain, yet retaining PAI‐1 binding capacity (Schar, Blouse, Minor, Peterson. J Biol Chem. 2008;283:28487–28496). This additional binding site is hypothesized to lie within an intrinsically disordered domain (IDD) of vitronectin. To localize the putative binding site, we constructed a truncated form of vitronectin containing 71 amino acids from the N‐terminus, including the SMB domain and an additional 24 amino acids from the IDD region. This portion of the IDD is rich in acidic amino acids, which are hypothesized to be complementary to several basic residues identified within an extensive vitronectin‐binding site mapped on PAI‐1 (Schar, Jensen, Christensen, Blouse, Andreasen, Peterson. J Biol Chem. 2008;283:10297–10309). Steady‐state and stopped‐flow fluorescence measurements demonstrate that the truncated form of vitronectin exhibits the same rapid biphasic association as full‐length vitronectin and that the IDD hosts the elusive second PAI‐1 binding site that lies external to the SMB domain of vitronectin. 相似文献
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Li Xiang‐yong Chen Yang‐chao Zhou Ke‐yuan Zhang Mei‐hong Luo Hai‐qing Kung Hsiang‐fu Zhou Xin 《Cell biology international》2010,34(11):1099-1104
BI‐1 (Bax inhibitor‐1), an apoptosis‐inhibiting gene belonging to the Bcl‐2 protein family, plays an important role in mitochondrial apoptosis pathway to suppress Bax‐induced apoptosis. To investigate the potential role of BI‐1 in promoting cell growth and tumorigenesis, in the present study we overexpressed the BI‐1 gene in NIH3T3 cells using the lentivirus‐mediated gene expression system. Our in vitro studies showed that NIH3T3 cells overexpressing BI‐1 displayed a significantly higher growth rate and formed more and larger colonies than the control cells. In addition, our in vivo studies indicated that the lenti‐BI‐1‐infected cells formed obvious tumours, while no tumours were formed by the control cells after subcutaneously injected into nude mice. These results strongly suggested that the BI‐1 gene might play a crucial role in neoplastic genesis and development. 相似文献
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Gonzalo Montoya Rodrigo Correa Jesús Arenas Lía Hoz Enrique Romo Rita Arroyo Margarita Zeichner‐David Higinio Arzate 《Journal of peptide science》2019,25(10)
A cementum protein 1‐derived peptide (CEMP1‐p1) consisting of 20 amino acids from the CEMP1's N‐terminus region: MGTSSTDSQQAGHRRCSTSN, and its role on the mineralization process in a cell‐free system, was characterized. CEMP1‐p1's physicochemical properties, crystal formation, and hydroxyapatite (HA) nucleation assays were performed. Crystals induced by CEMP1‐p1 were analyzed by scanning electron microscopy, Fourier‐transform infrared spectroscopy‐attenuated total reflectance (FTIR‐ATR), X‐ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and atomic force microscopy. The results indicate that CEMP1‐p1 lacks secondary structure, forms nanospheres that organize into three‐dimensional structures, possesses affinity to HA, and induces its nucleation. CEMP1‐p1 promotes the formation of spherical structures composed by densely packed prism‐like crystals, which revealed a Ca/P ratio of 1.56, corresponding to HA. FTIR‐ATR showed predominant spectrum peaks that correspond and are characteristic of HA and octacalcium phosphate (OCP). Analysis by XRD indicates that the crystals show planes with a preferential crystalline orientation for HA and for OCP. HRTEM showed interplanar distances that correspond to crystalline planes of HA and OCP. Crystals are composed by superimposed lamellae, which exhibit epitaxial growth, and each layer of the crystals is structured by nanocrystals. This study reveals that CEMP1‐p1 regulates HA crystal formation, somehow mimicking the in vivo process of mineralized tissues bioformation. 相似文献
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Plasminogenactivatorinhibitor1(PAI1)isaspecificphysiologicalinhibitorofurokinasetypeplasminogenactivator(uPA)andtissuetypeplasminogenactivator(tPA)[1].ChangesofPAI1mayinduceimbalancebetweenglomerularextracellularmatrix(ECM)synthesisanddegradation,thusleading… 相似文献