RESUMEN
Coagulation protease, factor VIIa (FVIIa), binds to endothelial cell protein C receptor (EPCR) and induces anti-inflammatory and endothelial barrier protective responses via protease-activated receptor-1 (PAR1)-mediated, biased signaling. Our recent studies had shown that the FVIIa-EPCR-PAR1 axis induces the release of extracellular vesicles (EVs) from endothelial cells. In the present study, we investigated the mechanism of FVIIa release of endothelial EVs (EEVs) and the contribution of FVIIa-released EEVs to anti-inflammatory and vascular barrier protective effects, in both in vitro and in vivo models. Multiple signaling pathways regulated FVIIa release of EVs from endothelial cells, but the ROCK-dependent pathway appeared to be a major mechanism. FVIIa-released EEVs were enriched with anti-inflammatory microRNAs (miRs), mostly miR10a. FVIIa-released EEVs were taken up readily by monocytes/macrophages and endothelial cells. The uptake of FVIIa-released EEVs by monocytes conferred anti-inflammatory phenotype to monocytes, whereas EEV uptake by endothelial cells resulted in barrier protection. In additional experiments, EEV-mediated delivery of miR10a to monocytes downregulated the expression of TAK1 and activation of the NF-κB-mediated inflammatory pathway. In in vivo experiments, administration of FVIIa-released EEVs to wild-type mice attenuated LPS-induced increased inflammatory cytokines in plasma and vascular leakage into vital tissues. The incorporation of anti-miR10a into FVIIa-released EEVs diminished the ability of FVIIa-released EEVs to confer cytoprotective effects. Administration of the ROCK inhibitor Y27632, which significantly inhibits FVIIa release of EEVs into the circulation, to mice attenuated the cytoprotective effects of FVIIa. Overall, our study revealed novel insights into how FVIIa induces cytoprotective effects and communicates with various cell types.
Asunto(s)
Células Endoteliales/metabolismo , Vesículas Extracelulares/metabolismo , Factor VIIa/metabolismo , Inflamación/metabolismo , MicroARNs/metabolismo , Animales , Células Endoteliales de la Vena Umbilical Humana , Humanos , Ratones Endogámicos C57BL , Monocitos/metabolismo , Células THP-1RESUMEN
Deep vein thrombosis (DVT) is the third most common cause of cardiovascular mortality. Several studies suggest that DVT occurs at the intersection of dysregulated inflammation and coagulation upon activation of inflammasome and secretion of interleukin 1ß (IL-1ß) in restricted venous flow conditions. Our recent studies showed a signaling adapter protein, Gab2 (Grb2-associated binder 2), plays a crucial role in propagating inflammatory signaling triggered by IL-1ß and other inflammatory mediators in endothelial cells. The present study shows that Gab2 facilitates the assembly of the CBM (CARMA3 [CARD recruited membrane-associated guanylate kinase protein 3]-BCL-10 [B-cell lymphoma 10]-MALT1 [mucosa-associated lymphoid tissue lymphoma translocation protein 1]) signalosome, which mediates the activation of Rho and NF-κB in endothelial cells. Gene silencing of Gab2 or MALT1, the effector signaling molecule in the CBM signalosome, or pharmacological inhibition of MALT1 with a specific inhibitor, mepazine, significantly reduced IL-1ß-induced Rho-dependent exocytosis of P-selectin and von Willebrand factor (VWF) and the subsequent adhesion of neutrophils to endothelial cells. MALT1 inhibition also reduced IL-1ß-induced NF-κB-dependent expression of tissue factor and vascular cell adhesion molecule 1. Consistent with the in vitro data, Gab2 deficiency or pharmacological inhibition of MALT1 suppressed the accumulation of monocytes and neutrophils at the injury site and attenuated venous thrombosis induced by the inferior vena cava ligation-induced stenosis or stasis in mice. Overall, our data reveal a previously unrecognized role of the Gab2-MALT1 axis in thromboinflammation. Targeting the Gab2-MALT1 axis with MALT1 inhibitors may become an effective strategy to treat DVT by suppressing thromboinflammation without inducing bleeding complications.
Asunto(s)
Trombosis , Trombosis de la Vena , Proteínas Adaptadoras Transductoras de Señales , Animales , Proteína 10 de la LLC-Linfoma de Células B/metabolismo , Proteínas Adaptadoras de Señalización CARD/metabolismo , Células Endoteliales/metabolismo , Guanilato-Quinasas/metabolismo , Inflamasomas/metabolismo , Inflamación , Mediadores de Inflamación , Interleucina-1beta/metabolismo , Ratones , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , FN-kappa B/metabolismo , Selectina-P/metabolismo , Tromboinflamación , Tromboplastina/metabolismo , Molécula 1 de Adhesión Celular Vascular/metabolismo , Trombosis de la Vena/genética , Factor de von Willebrand/metabolismoRESUMEN
Recurrent spontaneous or trauma-related bleeding into joints in hemophilia leads to hemophilic arthropathy (HA), a debilitating joint disease. Treatment of HA consists of preventing joint bleeding by clotting factor replacement, and in extreme cases, orthopedic surgery. We recently showed that administration of endothelial cell protein C receptor (EPCR) blocking monoclonal antibodies (mAb) markedly reduced the severity of HA in factor VIII (FVIII)-/- mice. EPCR blocking inhibits activated protein C (APC) generation and EPCR-dependent APC signaling. The present study was aimed to define the role of inhibition of APC anticoagulant activity, APC signaling, or both in suppressing HA. FVIII-/- mice were treated with a single dose of isotype control mAb, MPC1609 mAb, that inhibits anticoagulant, and signaling properties of APC, or MAPC1591 mAb that only blocks the anticoagulant activity of APC. Joint bleeding was induced by needle puncture injury. HA was evaluated by monitoring joint bleeding, change in joint diameter, and histopathological analysis of joint tissue sections for synovial hypertrophy, macrophage infiltration, neoangiogenesis, cartilage degeneration, and chondrocyte apoptosis. No significant differences were observed between MPC1609 and MAPC1591 in inhibiting APC anticoagulant activity in vitro and equally effective in correcting acute bleeding induced by the saphenous vein incision in FVIII-/- mice. Administration of MAPC1591, and not MPC1609, markedly reduced the severity of HA. MAPC1591 inhibited joint bleed-induced inflammatory cytokine interleukin-6 expression and vascular leakage in joints, whereas MPC1609 had no significant effect. Our data show that an mAb that selectively inhibits APC's anticoagulant activity without compromising its cytoprotective signaling offers a therapeutic potential alternative to treat HA.
Asunto(s)
Artritis , Hemofilia A , Animales , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales/uso terapéutico , Anticoagulantes/farmacología , Anticoagulantes/uso terapéutico , Receptor de Proteína C Endotelial , Hemartrosis/tratamiento farmacológico , Hemartrosis/patología , Hemartrosis/prevención & control , Hemofilia A/complicaciones , Hemofilia A/tratamiento farmacológico , Hemorragia , Ratones , Proteína C/metabolismoRESUMEN
BACKGROUND: Our recent studies suggest that sphingomyelin levels in the plasma membrane influence TF (tissue factor) procoagulant activity. The current study was performed to investigate how alterations to sphingomyelin metabolic pathway would affect TF procoagulant activity and thereby affect hemostatic and thrombotic processes. METHODS: Macrophages and endothelial cells were transfected with specific siRNAs or infected with adenoviral vectors to alter sphingomyelin levels in the membrane. TF activity was measured in factor X activation assay. Saphenous vein incision-induced bleeding and the inferior vena cava ligation-induced flow restriction mouse models were used to evaluate hemostasis and thrombosis, respectively. RESULTS: Overexpression of SMS (sphingomyelin synthase) 1 or SMS2 in human monocyte-derived macrophages suppresses ATP-stimulated TF procoagulant activity, whereas silencing SMS1 or SMS2 increases the basal cell surface TF activity to the same level as of ATP-decrypted TF activity. Consistent with the concept that sphingomyelin metabolism influences TF procoagulant activity, silencing of acid sphingomyelinase or neutral sphingomyelinase 2 or 3 attenuates ATP-induced enhanced TF procoagulant activity in macrophages and endothelial cells. Niemann-Pick disease fibroblasts with a higher concentration of sphingomyelin exhibited lower TF activity compared with wild-type fibroblasts. In vivo studies revealed that LPS+ATP-induced TF activity and thrombin generation were attenuated in ASMase-/- mice, while their levels were increased in SMS2-/- mice. Further studies revealed that acid sphingomyelinase deficiency leads to impaired hemostasis, whereas SMS2 deficiency increases thrombotic risk. CONCLUSIONS: Overall, our data indicate that alterations in sphingomyelin metabolism would influence TF procoagulant activity and affect hemostatic and thrombotic processes.
Asunto(s)
Hemostáticos , Trombosis , Ratones , Humanos , Animales , Esfingomielinas , Esfingomielina Fosfodiesterasa/genética , Células Endoteliales/metabolismo , Trombosis/genética , Hemostasis , Adenosina TrifosfatoRESUMEN
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with the hypercoagulable state. Tissue factor (TF) is the primary cellular initiator of coagulation. Most of the TF expressed on cell surfaces remains cryptic. Sphingomyelin (SM) is responsible for maintaining TF in the encrypted state, and hydrolysis of SM by acid sphingomyelinase (ASMase) increases TF activity. ASMase was shown to play a role in virus infection biology. In the present study, we investigated the role of ASMase in SARS-CoV-2 infection-induced TF procoagulant activity. Infection of human monocyte-derived macrophages (MDMs) with SARS-CoV-2 spike protein pseudovirus (SARS-CoV-2-SP-PV) markedly increased TF procoagulant activity at the cell surface and released TF+ extracellular vesicles. The pseudovirus infection did not increase either TF protein expression or phosphatidylserine externalization. SARS-CoV-2-SP-PV infection induced the translocation of ASMase to the outer leaflet of the plasma membrane, which led to the hydrolysis of SM in the membrane. Pharmacologic inhibitors or genetic silencing of ASMase attenuated SARS-CoV-2-SP-PV-induced increased TF activity. Inhibition of the SARS-CoV-2 receptor, angiotensin-converting enzyme-2, attenuated SARS-CoV-2-SP-PV-induced increased TF activity. Overall, our data suggest that SARS-CoV-2 infection activates the coagulation by decrypting TF through activation of ASMase. Our data suggest that the US Food and Drug Administration-approved functional inhibitors of ASMase may help treat hypercoagulability in patients with COVID-19.
Asunto(s)
COVID-19/sangre , Macrófagos/virología , Proteínas de la Membrana/fisiología , SARS-CoV-2 , Esfingomielina Fosfodiesterasa/fisiología , Glicoproteína de la Espiga del Coronavirus/fisiología , Trombofilia/etiología , Tromboplastina/fisiología , Enzima Convertidora de Angiotensina 2/fisiología , COVID-19/complicaciones , Micropartículas Derivadas de Células , Activación Enzimática , Humanos , Hidrólisis , Macrófagos/enzimología , Terapia Molecular Dirigida , Plásmidos , Transporte de Proteínas , Interferencia de ARN , ARN Interferente Pequeño/genética , Receptores Virales/fisiología , Esfingomielina Fosfodiesterasa/antagonistas & inhibidores , Esfingomielinas/fisiología , Trombofilia/sangre , Trombofilia/tratamiento farmacológico , Trombofilia/enzimologíaRESUMEN
Recombinant factor FVIIa (rFVIIa) is used as a hemostatic agent to treat bleeding disorders in hemophilia patients with inhibitors and other groups of patients. Our recent studies showed that FVIIa binds endothelial cell protein C receptor (EPCR) and induces protease-activated receptor 1 (PAR1)-mediated biased signaling. The importance of FVIIa-EPCR-PAR1-mediated signaling in hemostasis is unknown. In the present study, we show that FVIIa induces the release of extracellular vesicles (EVs) from endothelial cells both in vitro and in vivo. Silencing of EPCR or PAR1 in endothelial cells blocked the FVIIa-induced generation of EVs. Consistent with these data, FVIIa treatment enhanced the release of EVs from murine brain endothelial cells isolated from wild-type (WT), EPCR-overexpressing, and PAR1-R46Q-mutant mice, but not EPCR-deficient or PAR1-R41Q-mutant mice. In vivo studies revealed that administration of FVIIa to WT, EPCR-overexpressing, and PAR1-R46Q-mutant mice, but not EPCR-deficient or PAR1-R41Q-mutant mice, increased the number of circulating EVs. EVs released in response to FVIIa treatment exhibit enhanced procoagulant activity. Infusion of FVIIa-generated EVs and not control EVs to platelet-depleted mice increased thrombin generation at the site of injury and reduced blood loss. Administration of FVIIa-generated EVs or generation of EVs endogenously by administering FVIIa augmented the hemostatic effect of FVIIa. Overall, our data reveal that FVIIa treatment, through FVIIa-EPCR-PAR1 signaling, releases EVs from the endothelium into the circulation, and these EVs contribute to the hemostatic effect of FVIIa.
Asunto(s)
Endotelio Vascular/metabolismo , Vesículas Extracelulares/metabolismo , Factor VIIa/farmacología , Hemostasis/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Receptor PAR-1/metabolismo , Sustitución de Aminoácidos , Animales , Vesículas Extracelulares/genética , Hemostasis/genética , Humanos , Ratones , Ratones Noqueados , Mutación Missense , Receptor PAR-1/genética , Proteínas Recombinantes/farmacologíaRESUMEN
We recently showed that clotting factor VIIa (FVIIa) binding to endothelial cell protein C receptor (EPCR) induces anti-inflammatory signaling and protects vascular barrier integrity. Inflammation and vascular permeability are thought to be major contributors to the development of hemophilic arthropathy following hemarthrosis. The present study was designed to investigate the potential influence of FVIIa interaction with EPCR in the pathogenesis of hemophilic arthropathy and its treatment with recombinant FVIIa (rFVIIa). For this, we first generated hemophilia A (FVIII-/-) mice lacking EPCR (EPCR-/-FVIII-/-) or overexpressing EPCR (EPCR++ FVIII-/-). Joint bleeding was induced in FVIII-/-, EPCR-/-FVIII-/-, and EPCR++FVIII-/- mice by needle puncture injury. Hemophilic synovitis was evaluated by monitoring joint bleeding, change in joint diameter, and histopathological analysis of joint tissue sections. EPCR deficiency in FVIII-/- mice significantly reduced the severity of hemophilic synovitis. EPCR deficiency attenuated the elaboration of interleukin-6, infiltration of macrophages, and neoangiogenesis in the synovium following hemarthrosis. A single dose of rFVIIa was sufficient to fully prevent the development of milder hemophilic synovitis in EPCR-/-FVIII-/- mice. The development of hemophilic arthropathy in EPCR-overexpressing FVIII-/- mice did not significantly differ from that of FVIII-/- mice, and 3 doses of rFVIIa partly protected against hemophilic synovitis in these mice. Consistent with the data that EPCR deficiency protects against developing hemophilic arthropathy, administration of a single dose of EPCR-blocking monoclonal antibodies markedly reduced hemophilic synovitis in FVIII-/- mice subjected to joint bleeding. The present data indicate that EPCR could be an attractive new target to prevent joint damage in hemophilia patients.
Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Receptor de Proteína C Endotelial/deficiencia , Hemartrosis/prevención & control , Hemofilia A/complicaciones , Animales , Anticuerpos Monoclonales/farmacología , Citocinas/fisiología , Receptor de Proteína C Endotelial/antagonistas & inhibidores , Receptor de Proteína C Endotelial/inmunología , Receptor de Proteína C Endotelial/fisiología , Factor VIIa/uso terapéutico , Hemartrosis/tratamiento farmacológico , Hemartrosis/etiología , Hemartrosis/fisiopatología , Hemofilia A/tratamiento farmacológico , Hemofilia A/genética , Ratones , Ratones Noqueados , Punciones/efectos adversos , Ratas , Proteínas Recombinantes/uso terapéutico , Sinovitis/etiología , Sinovitis/prevención & controlRESUMEN
[Figure: see text].
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Mediadores de Inflamación/metabolismo , Inflamación/metabolismo , Pulmón/metabolismo , Infecciones Neumocócicas/metabolismo , Neumonía Bacteriana/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Citocinas/metabolismo , Modelos Animales de Enfermedad , Endotoxinas , Trampas Extracelulares/metabolismo , Femenino , Células Endoteliales de la Vena Umbilical Humana/patología , Humanos , Inflamación/genética , Inflamación/patología , Pulmón/microbiología , Pulmón/patología , Masculino , Ratones Noqueados , Infecciones Neumocócicas/genética , Infecciones Neumocócicas/microbiología , Infecciones Neumocócicas/patología , Neumonía Bacteriana/genética , Neumonía Bacteriana/microbiología , Neumonía Bacteriana/patología , Transducción de Señal , Trombina/metabolismoRESUMEN
OBJECTIVE: TF (Tissue factor) plays a key role in hemostasis, but an aberrant expression of TF leads to thrombosis. The objective of the present study is to investigate the effect of 4-hydroxy-2-nonenal (HNE), the most stable and major oxidant produced in various disease conditions, on the release of TF+ microvesicles into the circulation, identify the source of TF+ microvesicles origin, and assess their effect on intravascular coagulation and inflammation. Approach and Results: C57BL/6J mice were administered with HNE intraperitoneally, and the release of TF+ microvesicles into circulation was evaluated using coagulation assays and nanoparticle tracking analysis. Various cell-specific markers were used to identify the cellular source of TF+ microvesicles. Vascular permeability was analyzed by the extravasation of Evans blue dye or fluorescein dextran. HNE administration to mice markedly increased the levels of TF+ microvesicles and thrombin generation in the circulation. HNE administration also increased the number of neutrophils in the lungs and elevated the levels of inflammatory cytokines in plasma. Administration of an anti-TF antibody blocked not only HNE-induced thrombin generation but also HNE-induced inflammation. Confocal microscopy and immunoblotting studies showed that HNE does not induce TF expression either in vascular endothelium or circulating monocytes. Microvesicles harvested from HNE-administered mice stained positively with CD248 and α-smooth muscle actin, the markers that are specific to perivascular cells. HNE was found to destabilize endothelial cell barrier integrity. CONCLUSIONS: HNE promotes the release of TF+ microvesicles from perivascular cells into the circulation. HNE-induced increased TF activity contributes to intravascular coagulation and inflammation.
Asunto(s)
Aldehídos/toxicidad , Micropartículas Derivadas de Células/efectos de los fármacos , Inflamación/inducido químicamente , Estrés Oxidativo , Tromboplastina/metabolismo , Trombosis/inducido químicamente , Actinas/metabolismo , Aldehídos/administración & dosificación , Animales , Antígenos CD/metabolismo , Antígenos de Neoplasias/metabolismo , Coagulación Sanguínea/efectos de los fármacos , Micropartículas Derivadas de Células/metabolismo , Células Cultivadas , Citocinas/sangre , Femenino , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Inflamación/sangre , Mediadores de Inflamación/sangre , Masculino , Ratones Endogámicos C57BL , Trombina/metabolismo , Trombosis/sangreRESUMEN
Streptococcus pneumoniae is the leading cause of hospital community-acquired pneumonia. Patients with pneumococcal pneumonia may develop complicated parapneumonic effusions or empyema that can lead to pleural organization and subsequent fibrosis. The pathogenesis of pleural organization and scarification involves complex interactions between the components of the immune system, coagulation, and fibrinolysis. EPCR (endothelial protein C receptor) is a critical component of the protein C anticoagulant pathway. The present study was performed to evaluate the role of EPCR in the pathogenesis of S. pneumoniae infection-induced pleural thickening and fibrosis. Our studies show that the pleural mesothelium expresses EPCR. Intrapleural instillation of S. pneumoniae impairs lung compliance and lung volume in wild-type and EPCR-overexpressing mice but not in EPCR-deficient mice. Intrapleural S. pneumoniae infection induces pleural thickening in wild-type mice. Pleural thickening is more pronounced in EPCR-overexpressing mice, whereas it is reduced in EPCR-deficient mice. Markers of mesomesenchymal transition are increased in the visceral pleura of S. pneumoniae-infected wild-type and EPCR-overexpressing mice but not in EPCR-deficient mice. The lungs of wild-type and EPCR-overexpressing mice administered intrapleural S. pneumoniae showed increased infiltration of macrophages and neutrophils, which was significantly reduced in EPCR-deficient mice. An analysis of bacterial burden in the pleural lavage, the lungs, and blood revealed a significantly lower bacterial burden in EPCR-deficient mice compared with wild-type and EPCR-overexpressing mice. Overall, our data provide strong evidence that EPCR deficiency protects against S. pneumoniae infection-induced impairment of lung function and pleural remodeling.
Asunto(s)
Receptor de Proteína C Endotelial/deficiencia , Pulmón/metabolismo , Pleura/metabolismo , Derrame Pleural/metabolismo , Pleuresia/metabolismo , Neumonía Neumocócica/metabolismo , Streptococcus pneumoniae/patogenicidad , Animales , Carga Bacteriana , Células Cultivadas , Modelos Animales de Enfermedad , Receptor de Proteína C Endotelial/genética , Femenino , Fibrosis , Interacciones Huésped-Patógeno , Humanos , Pulmón/microbiología , Pulmón/patología , Pulmón/fisiopatología , Macrófagos/metabolismo , Macrófagos/microbiología , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Infiltración Neutrófila , Neutrófilos/metabolismo , Neutrófilos/microbiología , Pleura/microbiología , Pleura/patología , Derrame Pleural/microbiología , Derrame Pleural/patología , Derrame Pleural/fisiopatología , Pleuresia/microbiología , Pleuresia/patología , Pleuresia/fisiopatología , Neumonía Neumocócica/microbiología , Neumonía Neumocócica/patología , Neumonía Neumocócica/fisiopatologíaRESUMEN
Tissue factor (TF) is a cofactor for factor VIIa and the primary cellular initiator of coagulation. Typically, most TF on cell surfaces exists in a cryptic coagulant-inactive state but are transformed to a procoagulant form (decryption) following cell activation. Our recent studies in cell model systems showed that sphingomyelin (SM) in the outer leaflet of the plasma membrane is responsible for maintaining TF in an encrypted state in resting cells, and the hydrolysis of SM leads to decryption of TF. The present study was carried out to investigate the relevance of this novel mechanism in the regulation of TF procoagulant activity in pathophysiology. As observed in cell systems, administration of adenosine triphosphate (ATP) to mice enhanced lipopolysaccharide (LPS)-induced TF procoagulant activity in monocytes. Treatment of mice with pharmacological inhibitors of acid sphingomyelinase (ASMase), desipramine and imipramine, attenuated ATP-induced TF decryption. Interestingly, ASMase inhibitors also blocked LPS-induced TF procoagulant activity without affecting the LPS-induced de novo synthesis of TF protein. Additional studies showed that LPS induced translocation of ASMase to the outer leaflet of the plasma membrane and reduced SM levels in monocytes. Studies using human monocyte-derived macrophages and endothelial cells further confirmed the role of ASMase in LPS- and cytokine-induced TF procoagulant activity. Overall, our data indicate that LPS- or cytokine-induced TF procoagulant activity requires the decryption of newly synthesized TF protein by ASMase-mediated hydrolysis of SM. The observation that ASMase inhibitors attenuate TF-induced coagulation raises the possibility of their therapeutic use in treating thrombotic disorders associated with aberrant expression of TF.
Asunto(s)
Citocinas/metabolismo , Lipopolisacáridos/metabolismo , Esfingomielina Fosfodiesterasa/metabolismo , Tromboplastina/metabolismo , Trombosis/metabolismo , Animales , Coagulación Sanguínea , Células Endoteliales de la Vena Umbilical Humana , Humanos , Ratones Endogámicos C57BL , Monocitos/metabolismo , Trombina/metabolismoRESUMEN
OBJECTIVE: Recent studies showed that FVIIa (factor VIIa), upon binding to EPCR (endothelial cell protein C receptor), elicits endothelial barrier stabilization and anti-inflammatory effects via activation of PAR (protease-activated receptor)-1-mediated signaling. It is unknown whether FVIIa induces PAR1-dependent cytoprotective signaling through cleavage of PAR1 at the canonical site or a noncanonical site, similar to that of APC (activated protein C). Approach and Results: Mouse strains carrying homozygous R41Q (canonical site) or R46Q (noncanonical site) point mutations in PAR1 (QQ41-PAR1 and QQ46-PAR1 mice) were used to investigate in vivo mechanism of PAR1-dependent pharmacological beneficial effects of FVIIa. Administration of FVIIa reduced lipopolysaccharide-induced inflammation, barrier permeability, and VEGF (vascular endothelial cell growth factor)-induced barrier disruption in wild-type (WT) and QQ46-PAR1 mice but not in QQ41-PAR1 mice. In vitro signaling studies performed with brain endothelial cells isolated from WT, QQ41-PAR1, and QQ46-PAR1 mice showed that FVIIa activation of Akt (protein kinase B) in endothelial cells required R41 cleavage site in PAR1. Our studies showed that FVIIa cleaved endogenous PAR1 in endothelial cells, and FVIIa-cleaved PAR1 was readily internalized, unlike APC-cleaved PAR1 that remained on the cell surface. Additional studies showed that pretreatment of endothelial cells with FVIIa reduced subsequent thrombin-induced signaling. This process was dependent on ß-arrestin1. CONCLUSIONS: Our results indicate that in vivo pharmacological benefits of FVIIa in mice arise from PAR1-dependent biased signaling following the cleavage of PAR1 at the canonical R41 site. The mechanism of FVIIa-induced cytoprotective signaling is distinctly different from that of APC. Our data provide another layer of complexity of biased agonism of PAR1 and signaling diversity.
Asunto(s)
Antiinflamatorios/administración & dosificación , Permeabilidad Capilar/efectos de los fármacos , Células Endoteliales/efectos de los fármacos , Factor VIIa/administración & dosificación , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Neumonía/tratamiento farmacológico , Receptor PAR-1/metabolismo , Animales , Modelos Animales de Enfermedad , Endocitosis , Células Endoteliales/metabolismo , Endotoxinas , Femenino , Homocigoto , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Masculino , Ratones Transgénicos , Neumonía/inducido químicamente , Neumonía/genética , Neumonía/metabolismo , Mutación Puntual , Receptor PAR-1/genética , Transducción de SeñalRESUMEN
Recent studies show that endothelial cell protein C receptor (EPCR) interacts with diverse ligands, in addition to its known ligands protein C and activated protein C (APC). We showed in earlier studies that procoagulant clotting factor VIIa (FVIIa) binds EPCR and downregulates EPCR-mediated anticoagulation and induces an endothelial barrier protective effect. Here, we investigated the effect of FVIIa's interaction with EPCR on endothelial cell inflammation and lipopolysaccharide (LPS)-induced inflammatory responses in vivo. Treatment of endothelial cells with FVIIa suppressed tumor necrosis factor α (TNF-α)- and LPS-induced expression of cellular adhesion molecules and adherence of monocytes to endothelial cells. Inhibition of EPCR or protease-activated receptor 1 (PAR1) by either specific antibodies or small interfering RNA abolished the FVIIa-induced suppression of TNF-α- and LPS-induced expression of cellular adhesion molecules and interleukin-6. ß-Arrestin-1 silencing blocked the FVIIa-induced anti-inflammatory effect in endothelial cells. In vivo studies showed that FVIIa treatment markedly suppressed LPS-induced inflammatory cytokines and infiltration of innate immune cells into the lung in wild-type and EPCR-overexpressing mice, but not in EPCR-deficient mice. Mechanistic studies revealed that FVIIa treatment inhibited TNF-α-induced ERK1/2, p38 MAPK, JNK, NF-κB, and C-Jun activation indicating that FVIIa-mediated signaling blocks an upstream signaling event in TNFα-induced signaling cascade. FVIIa treatment impaired the recruitment of TNF-receptor-associated factor 2 into the TNF receptor 1 signaling complex. Overall, our present data provide convincing evidence that FVIIa binding to EPCR elicits anti-inflammatory signaling via a PAR1- and ß-arrestin-1 dependent pathway. The present study suggests new therapeutic potentials for FVIIa, which is currently in clinical use for treating bleeding disorders.
Asunto(s)
Receptor de Proteína C Endotelial/metabolismo , Factor VIIa/metabolismo , Inflamación/metabolismo , Receptor PAR-1/metabolismo , Transducción de Señal , Animales , Biomarcadores , Receptor de Proteína C Endotelial/genética , Regulación de la Expresión Génica , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Inflamación/genética , Mediadores de Inflamación/metabolismo , Lipopolisacáridos/efectos adversos , Lipopolisacáridos/inmunología , Ratones , Receptor PAR-1/genética , Factor de Necrosis Tumoral alfa/metabolismo , beta-Arrestinas/metabolismoRESUMEN
PURPOSE OF REVIEW: Endothelial cell protein C receptor (EPCR), a transmembrane glycoprotein present on the surface of endothelial cells and other cell types, is an essential component of the protein C (PC) anticoagulant system. EPCR is also shown to play a critical role in mediating activated protein C (APC)-induced cytoprotective signaling. The purpose of this review is to outline the mechanisms of EPCR-dependent cell signaling and discuss recent findings made in this area. RECENT FINDINGS: Recent studies showed that the cleavage of protease-activated receptor (PAR)1 at a noncanonical site by APC-EPCR or the canonical site by thrombin when PC occupies EPCR induces ß-arrestin-2-mediated biased cytoprotective signaling. Factor VIIa binding to EPCR is also shown to induce the cytoprotective signaling. EPCR is found to be a reliable surface marker for identifying human hematopoietic stem cells in culture. EPCR, binding to diverse ligands, is thought to play a role in the pathogenesis of severe malaria, immune functions, and cancer by either blocking the APC-mediated signaling or by mechanisms that are yet to be elucidated. SUMMARY: Recent studies provide a mechanistic basis to how EPCR contributes to PAR1-mediated biased signaling. EPCR may play a role in influencing a wide array of biological functions by binding to diverse ligands.
Asunto(s)
Células Endoteliales/metabolismo , Receptor de Proteína C Endotelial/metabolismo , Factor VIIa/metabolismo , Proteína C/metabolismo , Receptor PAR-1/metabolismo , Transducción de Señal , Animales , Células Endoteliales/patología , Células Madre Hematopoyéticas/metabolismo , Células Madre Hematopoyéticas/patología , Humanos , Malaria/metabolismo , Malaria/patología , Proteínas de Neoplasias/metabolismo , Neoplasias/metabolismo , Neoplasias/patología , Arrestina beta 2/metabolismoRESUMEN
Endothelial cell protein C receptor (EPCR) was first identified and isolated as a cellular receptor for protein C on endothelial cells. EPCR plays a crucial role in the protein C anticoagulant pathway by promoting protein C activation. In the last decade, EPCR has received wide attention after it was discovered to play a key role in mediating activated protein C (APC)-induced cytoprotective effects, including antiapoptotic, anti-inflammatory, and barrier stabilization. APC elicits cytoprotective signaling through activation of protease activated receptor-1 (PAR1). Understanding how EPCR-APC induces cytoprotective effects through activation of PAR1, whose activation by thrombin is known to induce a proinflammatory response, has become a major research focus in the field. Recent studies also discovered additional ligands for EPCR, which include factor VIIa, Plasmodium falciparum erythrocyte membrane protein, and a specific variant of the T-cell receptor. These observations open unsuspected new roles for EPCR in hemostasis, malaria pathogenesis, innate immunity, and cancer. Future research on these new discoveries will undoubtedly expand our understanding of the role of EPCR in normal physiology and disease, as well as provide novel insights into mechanisms for EPCR multifunctionality. Comprehensive understanding of EPCR may lead to development of novel therapeutic modalities in treating hemophilia, inflammation, cerebral malaria, and cancer.
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Antígenos CD/fisiología , Receptores de Superficie Celular/fisiología , Secuencia de Aminoácidos , Animales , Antígenos CD/química , Receptor de Proteína C Endotelial , Hemostasis/genética , Humanos , Inflamación/genética , Inflamación/metabolismo , Ligandos , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Terciaria de Proteína , Receptores de Superficie Celular/química , Homología de Secuencia de AminoácidoRESUMEN
Tissue factor pathway inhibitor (TFPI) is the primary inhibitor of the extrinsic coagulation cascade, and its expression is reported to be relatively stable. Various pathophysiologic agents have been shown to influence TFPI activity by regulating its expression or by modifying the protein. It is not clear how TFPI activity is regulated in normal physiology or in injury. Because thrombin and TFPI are locally elaborated in pleural injury, we sought to determine if thrombin could regulate TFPI in human pleural mesothelial cells (HPMCs). Thrombin significantly decreased TFPI mRNA and protein levels by > 70%. Thrombin-mediated down-regulation of TFPI promoted factor X activation by HPMCs. The ability of thrombin to significantly decrease TFPI mRNA and protein levels was maintained at nanomolar concentrations. Protease-activated receptor (PAR)-1, a mediator of thrombin signaling, is detectable in the mesothelium in human and murine pleural injury. PAR-1 silencing blocked thrombin-mediated decrements of TFPI in HPMCs. Thrombin activates PI3K/Akt and nuclear factor κB (NF-κB) signaling in HPMCs. Inhibition of PI3K (by PX-866) and NF-κB (by SN50) prevented thrombin-mediated TFPI mRNA and protein down-regulation. These are the first studies to demonstrate that thrombin decreases TFPI expression in HPMCs. Our findings demonstrate a novel mechanism by which thrombin regulates TFPI expression in HPMCs and promotes an unrestricted procoagulant response, and suggest that interactions between PI3K and NF-κB signaling pathways are linked in HPMCs and control TFPI expression. These findings raise the possibility that targeting this pathway could limit the ability of the mesothelium to support extravascular fibrin deposition and organization associated with pleural injury.
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Células Epiteliales/metabolismo , Lipoproteínas/metabolismo , FN-kappa B/metabolismo , Trombina/fisiología , Animales , Células Cultivadas , Regulación hacia Abajo , Expresión Génica , Humanos , Lipoproteínas/genética , Ratones Endogámicos C57BL , Fosfatidilinositol 3-Quinasas/metabolismo , Pleura/citología , Receptor PAR-1/metabolismoRESUMEN
Receptor tyrosine kinases, including the epidermal growth factor receptors (EGFR), are able to activate the mitogen-activated protein kinases (MAPK) via several adaptor proteins and protein kinases such as Raf. EGFR can be activated by a variety of extracellular stimuli including neutrophil elastase, but we are aware of no report as to whether Pseudomonas aeruginosa produced elastase (PE) could elicit such signalling through EGFR activation. We sought to test the inference that PE modulates inflammatory responses in human lung fibroblasts and that the process occurs by activation of the EGFR/MAPK pathways. We utilized IL-8 cytokine expression as a pathway-specific end point measure of the fibroblast inflammatory response to PE. Western blot analysis was performed to detect phosphorylation of EGFR and signal transduction intermediates. Northern blot, real-time PCR, and ELISA methods were utilized to determine cytokine gene expression levels. We found that PE induces phosphorylation of the EGFR and the extracellular signal-regulated proteins (ERK1/2) of the MAPK pathway, and nuclear translocation of NF-κB. Furthermore, enzymically active PE enhances IL-8 mRNA and protein secretion. Pretreatment of the cells with specific inhibitors of EGFR, MAPK kinase and NF-κB markedly attenuated the PE-induced signal proteins phosphorylation and IL-8 gene expression and protein secretion. Collectively, the data show that PE produced by Pseudomonas aeruginosa can modulate lung inflammation by exploiting the EGFR/ERK signalling cascades and enhancing IL-8 production in the lungs via NF-κB activation.
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Proteínas Bacterianas/metabolismo , Fibroblastos/metabolismo , Inflamación/metabolismo , Metaloendopeptidasas/metabolismo , Línea Celular , Núcleo Celular/metabolismo , Citocinas/genética , Citocinas/metabolismo , Receptores ErbB/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Expresión Génica , Humanos , Inflamación/genética , Interleucina-8/genética , Interleucina-8/metabolismo , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , FN-kappa B/metabolismo , Fosforilación , Transporte de Proteínas , Transducción de SeñalRESUMEN
OBJECTIVE: 4-hydroxy-2-nonenal (HNE) is one of the major aldehydes formed during lipid peroxidation and is believed to play a role in the pathogenesis of atherosclerosis. The objective of the present study is to investigate the effect of HNE on tissue factor (TF) procoagulant activity expressed on cell surfaces. APPROACH AND RESULTS: TF activity and antigen levels on intact cells were measured using factor Xa generation and TF monoclonal antibody binding assays, respectively. Exposure of phosphatidylserine on the cell surface was analyzed using thrombin generation assay or by binding of a fluorescent dye-conjugated annexin V. 2',7'-dichlorodihydrofluorescein diacetate was used to detect the generation of reactive oxygen species. Our data showed that HNE increased the procoagulant activity of unperturbed THP-1 cells that express traces of TF antigen, but had no effect on unperturbed endothelial cells that express no measurable TF antigen. HNE increased TF procoagulant activity but not TF antigen of both activated monocytic and endothelial cells. HNE treatment generated reactive oxygen species, activated p38 mitogen-activated protein kinase, and increased the exposure of phosphatidylserine at the outer leaflet in THP-1 cells. Treatment of THP-1 cells with an antioxidant, N-acetyl cysteine, suppressed the above HNE-induced responses and negated the HNE-mediated increase in TF activity. Blockade of p38 mitogen-activated protein kinase activation inhibited HNE-induced phosphatidylserine exposure and increased TF activity. CONCLUSIONS: HNE increases TF coagulant activity in monocytic cells through a novel mechanism involving p38 mitogen-activated protein kinase activation that leads to enhanced phosphatidylserine exposure at the cell surface.
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Aldehídos/farmacología , Monocitos/efectos de los fármacos , Fosfatidilserinas/metabolismo , Transducción de Señal/efectos de los fármacos , Tromboplastina/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Acetilcisteína/farmacología , Antioxidantes/farmacología , Coagulación Sanguínea/efectos de los fármacos , Línea Celular Tumoral , Micropartículas Derivadas de Células/efectos de los fármacos , Micropartículas Derivadas de Células/metabolismo , Citocinas/farmacología , Relación Dosis-Respuesta a Droga , Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Activación Enzimática , Factor Xa/metabolismo , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Humanos , Peroxidación de Lípido/efectos de los fármacos , Lipopolisacáridos/farmacología , Monocitos/enzimología , Monocitos/inmunología , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Trombina/metabolismo , Factores de TiempoRESUMEN
BACKGROUND: Factor VIIa induces the release of extracellular vesicles (EVs) from endothelial cells (EEVs). Factor VIIa-released EEVs are enriched with microRNA-10a (miR10a) and elicit miR10a-dependent cytoprotective responses. OBJECTIVES: To investigate mechanisms by which FVIIa induces miR10a expression in endothelial cells and sorts miR10a into the EVs. METHODS: Activation of Elk-1 and TWIST1 expression was analyzed by immunofluorescence microscopy and immunoblot analysis. Small interfering RNA silencing approach was used to knock down the expression of specific genes in endothelial cells. EVs secreted from endothelial cells or released into circulation in mice were isolated by centrifugation and quantified by nanoparticle tracking analysis. Factor VIIa or EVs were injected into mice; mice were challenged with lipopolysaccharides to assess the cytoprotective effects of FVIIa or EVs. RESULTS: FVIIa activation of ERK1/2 triggered the activation of Elk-1, which led to the induction of TWIST1, a key transcription factor involved in miR10a expression. Factor VIIa also induced the expression of La, a small RNA-binding protein. Factor VIIa-driven acid sphingomyelinase (ASM) activation and the subsequent activation of the S1P receptor pathway were responsible for the induction of La. Silencing of ASM or La significantly reduced miR10a levels in FVIIa-released EEVs without affecting the cellular expression of miR10a. Factor VIIa-EEVs from ASM knocked-down cells failed to provide cytoprotective responses in cell and murine model systems. Administration of FVIIa protected wild-type but not ASM-/- mice against lipopolysaccharide-induced inflammation and vascular leakage. CONCLUSION: Our data suggest that enhanced cellular expression of miR10a coupled with La-dependent sorting of miR10a is responsible for enriching FVIIa-released EVs with miR10a.
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Vesículas Extracelulares , MicroARNs , Ratones , Animales , Factor VIIa/metabolismo , Células Endoteliales/metabolismo , Transducción de Señal , Lipopolisacáridos/metabolismo , Vesículas Extracelulares/metabolismo , MicroARNs/genética , MicroARNs/metabolismoRESUMEN
Recent studies have shown that factor VIIa (FVIIa) binds to the endothelial cell protein C receptor (EPCR), a cellular receptor for protein C and activated protein C, but the physiologic significance of this interaction is unclear. In the present study, we show that FVIIa, upon binding to EPCR on endothelial cells, activates endogenous protease activated receptor-1 (PAR1) and induces PAR1-mediated p44/42 mitogen-activated protein kinase (MAPK) activation. Pretreatment of endothelial cells with FVIIa protected against thrombin-induced barrier disruption. This FVIIa-induced, barrier-protective effect was EPCR dependent and did not involve PAR2. Pretreatment of confluent endothelial monolayers with FVIIa before thrombin reduced the development of thrombin-induced transcellular actin stress fibers, cellular contractions, and paracellular gap formation. FVIIa-induced p44/42 MAPK activation and the barrier-protective effect are mediated via Rac1 activation. Consistent with in vitro findings, in vivo studies using mice showed that administration of FVIIa before lipopolysaccharide (LPS) treatment attenuated LPS-induced vascular leakage in the lung and kidney. Overall, our present data provide evidence that FVIIa bound to EPCR on endothelial cells activates PAR1-mediated cell signaling and provides a barrier-protective effect. These findings are novel and of great clinical significance, because FVIIa is used clinically for the prevention of bleeding in hemophilia and other bleeding disorders.