scholarly journals Protective Effects of Eicosapentaenoic Acid on the Glomerular Endothelium via Inhibition of EndMT in Diabetes

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Toshinori Yasuzawa ◽  
Tomomi Nakamura ◽  
Shigeru Ueshima ◽  
Akira Mima

Diabetes-induced endothelial pathologies are hypothesized to lead to the progression of diabetic kidney disease (DKD). The endothelial to mesenchymal transition (EndMT) possibly induces fibrosis, leading to glomerulosclerosis in the kidney. Furthermore, this could lead to albuminuria in diabetic nephropathy due to glomerular endothelial dysfunction. Eicosapentaenoic acid (EPA), purified from fish oil, decreases inflammatory cytokine levels in glomerulonephritis. Here, we aimed at finding whether ethyl eicosapentaenoate (EPA-E) exerts renal protective effects via EndMT inhibition. To find out whether EPA inhibits EndMT in vitro, the changes in CD31 expression were studied in cultured mouse endothelial cells. The addition of the conditioned medium from the adipocyte culture significantly decreased the protein levels of CD31, while the addition of EPA-E partially reversed this inhibition. Further, EndMT inhibition by EPA-E treatment might occur via the inhibition of the protein kinase Cβ (PKCβ)/transforming growth factor-β (TGF-β)/plasminogen activator inhibitor-1 (PAI-1) signaling and not via microRNAs. Streptozotocin-induced diabetic mice fed a high-fat diet (60% from fat) exhibited mesangial expansion and albuminuria. Induction of EPA-E ameliorated the mesangial expansion and decreased albuminuria without affecting blood pressure, triglyceride and free fatty acid levels, and intraperitoneal glucose. These findings suggest that EPA-E exerts renal protective effects on endothelial cells, by normalizing EndMT followed by the PKCβ/TGF-β/PAI-1 signaling. Thus, EPA-E has the potential for imparting renal protection by regulating EndMT in DKD.

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Qi Liu ◽  
Xiang Fan ◽  
Helen Brogren ◽  
Ming-Ming Ning ◽  
Eng H Lo ◽  
...  

Aims: Plasminogen activator inhibitor-1 (PAI-1) is the main and potent endogenous tissue-type plasminogen activator (tPA) inhibitor, but an important question on whether PAI-1 in blood stream responds and interferes with the exogenously administered tPA remains unexplored. We for the first time investigated temporal profiles of PAI-1 concentration and activity in circulation after stroke and tPA administration in rats. Methods: Permanent MCAO focal stroke of rats were treated with saline or 10mg/kg tPA at 3 hours after stroke (n=10 per group). Plasma (platelet free) PAI-1 antigen and activity levels were measured by ELISA at before stroke, 3, 4.5 (1.5 hours after saline or tPA treatments) and 24 hours after stroke. Since vascular endothelial cells and platelets are two major cellular sources for PAI-1 in circulation, we measured releases of PAI-1 from cultured endothelial cells and isolated platelets after direct tPA (4 μg/ml) exposures for 60 min in vitro by ELISA (n=4 per group). Results: At 3 hours after stroke, both plasma PAI-1 antigen and activity were significantly increased (3.09±0.67, and 3.42±0.57 fold of before stroke baseline, respectively, all data are expressed as mean±SE). At 4.5 hours after stroke, intravenous tPA administration significantly further elevated PAI-1 antigen levels (5.26±1.24), while as expected that tPA neutralized most elevated PAI-1 activity (0.33±0.05). At 24 hours after stroke, PAI-1 antigen levels returned to the before baseline level, however, there was a significantly higher PAI-1 activity (2.51±0.53) in tPA treated rats. In vitro tPA exposures significantly increased PAI-1 releases into culture medium in cultured endothelial cells (1.65±0.08) and platelets (2.02±0.17). Conclution: Our experimental results suggest that tPA administration may further elevate stroke-increased blood PAI-1 concentration, but also increase PAI-1 activity at late 24 hours after stroke. The increased PAI-1 releases after tPA exposures in vitro suggest tPA may directly stimulate PAI-1 secretions from vascular walls and circulation platelets, which partially contributes to the PAI-1 elevation observed in focal stroke rats. The underlying regulation mechanisms and pathological consequence need further investigation.


Blood ◽  
1996 ◽  
Vol 87 (10) ◽  
pp. 4204-4213 ◽  
Author(s):  
S Handt ◽  
WG Jerome ◽  
L Tietze ◽  
RR Hantgan

Time-dependent thrombolytic resistance is a critical problem in thrombolytic therapy for acute myocardial infarction. Platelets have been regarded as the main source of plasminogen activator inhibitor-1 (PAI-1) found in occlusive platelet-rich clots. However, endothelial cells are also known to influence the fibrinolytic capacity of blood vessels, but their ability to actively mediate time-dependent thrombolytic resistance has not been fully established. We will show that, in vitro, tumor necrosis factor-alpha-stimulated endothelial cells secrete large amounts of PAI-1 over a period of hours, which then binds to fibrin and protects the clot from tissue plasminogen activator- induced fibrinolysis. In vivo, endothelial cells covering atherosclerotic plaques are influenced by cytokines synthesized by plaque cells. Therefore, we propose that continuous activation of endothelial cells in atherosclerotic blood vessels, followed by elevated PAI-1 secretion and storage of active PAI-1 in the fibrin matrix, leads to clot stabilization. This scenario makes endothelial cells a major factor in time-dependent thrombolytic resistance.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2502-2502 ◽  
Author(s):  
Cinara Echart ◽  
Barbara Graziadio ◽  
Cinzia Repice ◽  
Mario Boccadoro ◽  
Antonio Palumbo ◽  
...  

Abstract Introduction: Patients with Multiple myeloma are at relatively high risk of developing thromboembolic events, usually deep vein thromboses (DVT). There are numerous contributing factors, including therapy, such as thalidomide, where DVT has been identified as a major toxicity, especially when thalidomide is used in combination with other treatments such as dexamethasone. The mechanisms by which thalidomide predisposes to thrombosis are not well understood. Defibrotide (DF) is an orally biovailable polydisperse oligonucleotide with anti-thrombotic, pro-fibrinolytic and anti-adhesive properties. Previously, DF has been shown to dose-dependently counteracted the increase in Plasminogen Activator Inhibitor-1 (PAI-1) expression and decrease on tissue plasminogen activator (t-PA) activity after lipopolysaccharide (LPS) stimulation of endothelial cells in vitro. Methods and Results: We have conducted in vitro studies using human microvascular endothelial cells (HMEC) in order to investigate the effect of different doses of thalidomide on various fibrinolytic factors. In addition, we evaluated whether DF modulates changes of fibrinolysis induced by thalidomide. HMEC were treated with 50 and 100μg/ml of thalidomide for 24 hours in presence and absence of DF (at a dose of 150μg/ml). t-PA and PAI-1 gene expression were evaluated through real time polymerase chain reaction (RT-PCR) of cDNA prepared from HMEC. Release of t-PA and PAI-1 were evaluated by imunoenzymatic assay (ELISA). Furthermore, we evaluated the fibrinolytic activity of cell surpernatant using a fibrin clot plate assay. In this method the fibrin clot was formed by mixing fibrinogen, plasminogen and thrombin. The plasmin generated by the cell surpernatant was able to digest fibrin and also hydrolyzed the chromogenic substrate S-2251. The RT-PCR results showed that thalidomide reduces t-PA (2.2 fold) and increases PAI-1 gene expression (4.0 fold) in HMEC cells, whereas DF was able to counteract this effect by up-regulating the t-PA and down-regulating PAI-1 gene expression induced by thalidomide (8.8 and 2.0 fold, respectivielly). Similar results was observed analyzing t-PA release by HMEC cells treated with different concentrations of thalidomide with and without DF. Thalidomide significantly reduces the t-PA released in both concentrations (p<0.001) and DF significantly increase the release of t-PA reduced by thalidomide (p<0.01). The changes of fibrinolytic activity in HMEC by thalidomide and the capacity of DF to restore the fibrinolysis was confirmed by analyzing the lyses of fibrin clots with endothelial cell surpernatant (p<0.01). Conclusions: These results show that DF is able to counteract the alterations of fibrinolytic factors in HMEC treated with thalidomide. Whilst further studies in preclinical MM models are underway, these data suggest a potential role for DF in the prevention of DVT induced by thalidomide and support ongoing clinical trials of DF in combination with thalidomide-based treatment.


1990 ◽  
Vol 111 (2) ◽  
pp. 743-755 ◽  
Author(s):  
M S Pepper ◽  
D Belin ◽  
R Montesano ◽  
L Orci ◽  
J D Vassalli

Tightly controlled proteolytic degradation of the extracellular matrix by invading microvascular endothelial cells is believed to be a necessary component of the angiogenic process. We have previously demonstrated the induction of plasminogen activators (PAs) in bovine microvascular endothelial (BME) cells by three agents that induce angiogenesis in vitro: basic FGF (bFGF), PMA, and sodium orthovanadate. Surprisingly, we find that these agents also induce plasminogen activator inhibitor-1 (PAI-1) activity and mRNA in BME cells. We also find that transforming growth factor-beta 1 (TGF-beta 1), which in vitro modulates a number of endothelial cell functions relevant to angiogenesis, also increases both PAI-1 and urokinase-type PA (u-PA) mRNA. Thus, production of both proteases and protease inhibitors is increased by angiogenic agents and TGF-beta 1. However, the kinetics and amplitude of PAI-1 and u-PA mRNA induction by these agents are strikingly different. We have used the ratio of u-PA:PAI-1 mRNA levels as an indicator of proteolytic balance. This ratio is tilted towards enhanced proteolysis in response to bFGF, towards antiproteolysis in response to TGF-beta 1, and is similar to that in untreated cultures when the two agents are added simultaneously. Using an in vitro angiogenesis assay in three-dimensional fibrin gels, we find that TGF-beta 1 inhibits the bFGF-induced formation of tube-like structures, resulting in the formation of solid endothelial cell cords within the superficial parts of the gel. These results suggest that a net positive proteolytic balance is required for capillary lumen formation. A novel perspective is provided on the relationship between extracellular matrix invasion, lumen formation, and net proteolytic balance, thereby reflecting the interplay between angiogenesis-modulating cytokines such as bFGF and TGF-beta 1.


2018 ◽  
Vol 47 (4) ◽  
pp. 346-350
Author(s):  
Patrycja Sosinska-Zawierucha ◽  
Ewa Baum ◽  
Beata Mackowiak ◽  
Monika Misian ◽  
Andrzej Bręborowicz

Background/aims: Hemodialysis causes the systemic inflammatory response, which may affect the function of endothelial cells. Methods: We studied the effect of the serum obtained after a hemodialysis session, compared to serum collected before the start of the treatment, on the gene expression and secretory activity of arterial endothelial cells (AECs) and venous endothelial cells (VECs) in in vitro culture. Results: Serum collected at the end of the hemodialysis session increased expression of the studied genes in VECs, and at the same time decreased their expression in AECs. Secretory activity was increased in VEC: (interleukin-6 [IL-6] +29%, p < 0.05, von Willebrand factor +23%, p < 0.02; tissue plasminogen activator [t-PA] +35%, p < 0.002, t-PA/plasminogen activator inhibitor-1 [PAI-1] ratio + 57%, p < 0.005). In AEC, synthesis of IL-6 and vascular endothelial growth factor were reduced (–36%, p < 0.02, –34%, p < 0.05, respectively) and the tPA/PAI-1 ratio was increased (+22%, p < 0.01). Conclusions: Hemodialysis induces the inflammatory, procoagulant, and profibrinolytic activity of VEC, whereas suppression of AEC is observed at the same time. Video Journal Club ‘Cappuccino with Claudio Ronco’ at https://www.karger.com/Journal/ArticleNews/223997?sponsor=52


2019 ◽  
Vol 20 (20) ◽  
pp. 5076
Author(s):  
Cheng-Ying Hsieh ◽  
Joen-Rong Sheu ◽  
Chih-Hao Yang ◽  
Wei-Lin Chen ◽  
Jie-Heng Tsai ◽  
...  

Thrombin is an essential procoagulant and profibrotic mediator. However, its implication in tuberculous pleural effusion (TBPE) remains unknown. The effusion thrombin and plasminogen activator inhibitor-1 (PAI-1) levels were measured among transudative pleural effusion (TPE, n = 22) and TBPE (n = 24) patients. Pleural fibrosis, identified as radiological residual pleural thickening (RPT) and shadowing, was measured at 12-month follow-up. Moreover, in vivo and in vitro effects of thrombin on PAI-1 expression and mesothelial–mesenchymal transition (MMT) were assessed. We demonstrated the effusion thrombin levels were significantly higher in TBPE than TPE, especially greater in TBPE patients with RPT > 10mm than those without, and correlated positively with PAI-1 and pleural fibrosis area. In carbon black/bleomycin-treated mice, knockdown of protease-activated receptor-1 (PAR-1) markedly downregulated α-smooth muscle actin (α-SMA) and fibronectin, and attenuated pleural fibrosis. In pleural mesothelial cells (PMCs), thrombin concentration-dependently increased PAI-1, α-SMA, and collagen I expression. Specifically, Mycobacterium tuberculosis H37Ra (MTBRa) induced thrombin production by PMCs via upregulating tissue factor and prothrombin, and PAR-1 silencing considerably abrogated MTBRa−stimulated PAI-1 expression and MMT. Consistently, prothrombin/PAR-1 expression was evident in the pleural mesothelium of TBPE patients. Conclusively, thrombin upregulates PAI-1 and MMT and may contribute to tuberculous pleural fibrosis. Thrombin/PAR-1 inhibition may confer potential therapy for pleural fibrosis.


Author(s):  
J.C. Lewis ◽  
R.R. Hantgan ◽  
W.G. Jerome ◽  
K.G. Grant ◽  
A. Dekker ◽  
...  

Thrombosis, the major clinical sequelae to atherosclerosis, is complex and encompasses a multiplicity of interactions among plasma proteins, platelets and other blood cells, and vascular endothelial cells. Thrombolysis, in a fashion paralleling thrombus progression, is also influenced by a multiplicity of interactions, and recent evidence has suggested that both platelets and endothelial cells play a role in prolonging the lytic process. This prolongation is detrimental to prognosis following vascular occlusion. We have previously reported that thrombin-stimulated platelets will prolong clot lysis when included in an in-vitro assay comprised of tissue-type plasminogen activator, plasminogen, and fibrin(ogen). This observation has been expanded in the present study to included TNF stimulated human umbilical vein endothelial cells, and our data document the association of platelet and EC derived PAI-1 with the fibrin network. HUVEC grown on carbon-stabilized, formvar-coated gold grids for whole mount IVEM were stimulated with tumor necrosis factor, prior to clot initiation and subsequent lysis, by addition to the cultures of fibrinogen, t-PA, plasminogen and thrombin-stimulated platelets. At selected times of lysis following polymerization, based upon laser light scattering kinetic studies, the samples were fixed and processed for PAI-1 localization using the immunogold technique. When observed by SEM, the partially lysed thrombi consisted of an anastomosing fibrin network that extended from endothelial cell surfaces (Figure 1). Within the thrombus, the delicate, branching fibrin strands often were focused at points containing the activated platelets. The interaction of fibrin with endothelial cells was evidenced by IVEM as a delicate extracellular array extending between and among adjacent cells (Figure 2 a,b). Immunogold probes, documenting PAI-1, were distributed in clusters along the fibrin (Figures lb,c). PA1-1, although cellular in origin, was not associated with the surfaces of either platelets or endothelial cells. The specificity of PAI-1 localization was verified through inclusion of a non-related immunogold probe which bound in substantially lower concentration and without site selectivity (Figure 2c). We conclude that HUVEC and platelets modulate thrombolysis through the release of PAI-1 which binds to fibrin and retards plasminogen activation.


1996 ◽  
Vol 75 (04) ◽  
pp. 600-606 ◽  
Author(s):  
Rui-Jin Shi ◽  
Patricia J Simpson-Haidaris ◽  
Victor J Marder ◽  
David J Silverman ◽  
Lee Ann Sporn

SummaryChanges in PAI-1 expression in human umbilical vein endothelial cells (HUVEC) were studied following in vitro infection with Rickettsia rickettsii. A 1.8-fold increase in secreted PAI-1 activity occurred in infected versus control cultures (p = 0.03) at 24 h but not at earlier timepoints. A similar increase (1.4-fold) in secreted PAI-1 antigen (p <0.005) was measured by ELISA. To determine whether this increase was due to increased synthesis of PAI-1, HUVEC were metabolically labeled with 35S-methionine concurrent with R. rickettsii infection. Such infection resulted in a 1.9-fold increase in labeled PAI-1 in the medium at 24 h (p = 0.036). Increase in steady-state levels of PAI-1 mRNA were detected as early as 18 h by Northern blot analysis, peaking (5.5-fold) at approximately 24 h. These results indicate that PAI-1 production is increased in RR-infected endothelial cells, an effect that may contribute to the vascular occlusions noted in Rocky Mountain spotted fever.


1992 ◽  
Vol 20 (1) ◽  
pp. 61-65
Author(s):  
Elisabetta Cenni ◽  
Gabriela Ciapetti ◽  
Susanna Stea ◽  
Alessandro Di Leo ◽  
Daniela Cavedagna ◽  
...  

In order to evaluate in vitro the suitability of various prosthetic materials for endothelial seeding, human endothelial cells derived from the umbilical vein were placed in direct contact with a variety of polymers. As a control, endothelial cells were cultured in the absence of material. After 24, 48, 72 and 96 hours, the cells were counted and a viability test with neutral red was performed. Assays of 6-keto prostaglandinFla (6-keto-PGF1a), tissue plasminogen activator (tPA) and plasminogen activator inhibitor 1 (PAI-1) were carried out on the supernatants. The cell counting technique demonstrated growth inhibition in the cell populations in contact with Woven Dacron® and Double Velour Dacron® in comparison with control cell cultures. Vital staining with neutral red, always sharply positive in the controls, was weak in the cells placed in contact with the materials. The 6-keto-PGF1a concentration in the supernatant was similar to the control level in the populations in contact with Woven Dacron® and Double Velour Dacron®. The tPA synthesis was higher in the cells exposed to the assayed materials compared to control values, while the PAI-1 concentration in the supernatant was lower in the cultures in contact with all materials.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Fang Sun ◽  
Ke Hu

Transforming growth factor-β(TGF-β) signaling and TGF-β-promoted epithelial-to-mesenchymal transition (EMT) have been postulated to be the common pathway causing pulmonary fibrosis. However, the up- or downstreaming markers of TGF-β-induced EMT still need to be further recognized. In the present study, we investigated the regulation on Krüppel-like factor 4 (KLF-4) and plasminogen activator inhibitor-1 (PAI-1) by TGF-βin the murine lung epithelial LA-4 cells and then examined the regulation of both markers in the TGF-β-induced EMT by the PAI-1 knockdown or the KLF-4 overexpression. Our study indicated that TGF-βinduced EMT in mouse LA-4 lung epithelial cells via reducing E-cadherin, while promoting Collagen I andα-SMA. And PAI-1 was upregulated, whereas KLF-4 was downregulated in the TGF-β-induced EMT model in LA-4 cells. Moreover, the siRNA-mediated PAI-1 knockdown inhibited the TGF-β-induced EMT, whereas the adenovirus-medicated KLF-4 overexpression markedly reduced the PAI-1 expression and inhibited the TGF-β-induced EMT in LA-4 cells. In conclusion, our study confirmed the downregulation of KLF-4 in the TGF-β-induced EMT in LA-4 cells. And the KLF-4 overexpression significantly reduced the TGF-β-induced PAI-1 and thus inhibited the TGF-β-induced EMT in mouse lung epithelial LA-4 cells. It implies that KLF-4 might be a promising target for effective control of the pulmonary fibrosis.


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