RESUMO
A hypercoagulable state, chronic inflammation, and increased risk of venous thrombosis and stroke are prominent features in patients with sickle cell disease (SCD). Coagulation factor XII (FXII) triggers activation of the contact system that is known to be involved in both thrombosis and inflammation, but not in physiological hemostasis. Therefore, we investigated whether FXII contributes to the prothrombotic and inflammatory complications associated with SCD. We found that when compared with healthy controls, patients with SCD exhibit increased circulating biomarkers of FXII activation that are associated with increased activation of the contact pathway. We also found that FXII, but not tissue factor, contributes to enhanced thrombin generation and systemic inflammation observed in sickle cell mice challenged with tumor necrosis factor α. In addition, FXII inhibition significantly reduced experimental venous thrombosis, congestion, and microvascular stasis in a mouse model of SCD. Moreover, inhibition of FXII attenuated brain damage and reduced neutrophil adhesion to the brain vasculature of sickle cell mice after ischemia/reperfusion induced by transient middle cerebral artery occlusion. Finally, we found higher FXII, urokinase plasminogen activator receptor, and αMß2 integrin expression in neutrophils of patients with SCD compared with healthy controls. Our data indicate that targeting FXII effectively reduces experimental thromboinflammation and vascular complications in a mouse model of SCD, suggesting that FXII inhibition may provide a safe approach for interference with inflammation, thrombotic complications, and vaso-occlusion in patients with SCD.
Assuntos
Anemia Falciforme , Fator XII , Animais , Camundongos , Anemia Falciforme/complicações , Anemia Falciforme/metabolismo , Fator XII/metabolismo , Inflamação , Acidente Vascular Cerebral , Trombose/metabolismoRESUMO
Polyphosphate is a procoagulant inorganic polymer of linear-linked orthophosphate residues. Multiple investigations have established the importance of platelet polyphosphate in blood coagulation; however, the mechanistic details of polyphosphate homeostasis in mammalian species remain largely undefined. In this study, xenotropic and polytropic retrovirus receptor 1 (XPR1) regulated polyphosphate in platelets and was implicated in thrombosis in vivo. We used bioinformatic analyses of omics data to identify XPR1 as a major phosphate transporter in platelets. XPR1 messenger RNA and protein expression inversely correlated with intracellular polyphosphate content and release. Pharmacological interference with XPR1 activity increased polyphosphate stores, led to enhanced platelet-driven coagulation, and amplified thrombus formation under flow via the polyphosphate/factor XII pathway. Conditional gene deletion of Xpr1 in platelets resulted in polyphosphate accumulation, accelerated arterial thrombosis, and augmented activated platelet-driven pulmonary embolism without increasing bleeding in mice. These data identify platelet XPR1 as an integral regulator of platelet polyphosphate metabolism and reveal a fundamental role for phosphate homeostasis in thrombosis.
Assuntos
Plaquetas/metabolismo , Polifosfatos/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Receptores Virais/metabolismo , Trombose/metabolismo , Animais , Transporte Biológico , Coagulação Sanguínea , Fator XII/metabolismo , Feminino , Masculino , Camundongos , Trombose/sangue , Receptor do Retrovírus Politrópico e XenotrópicoRESUMO
SARS-CoV-2 vaccine ChAdOx1 nCoV-19 (AstraZeneca) causes a thromboembolic complication termed vaccine-induced immune thrombotic thrombocytopenia (VITT). Using biophysical techniques, mouse models, and analysis of VITT patient samples, we identified determinants of this vaccine-induced adverse reaction. Super-resolution microscopy visualized vaccine components forming antigenic complexes with platelet factor 4 (PF4) on platelet surfaces to which anti-PF4 antibodies obtained from VITT patients bound. PF4/vaccine complex formation was charge-driven and increased by addition of DNA. Proteomics identified substantial amounts of virus production-derived T-REx HEK293 proteins in the ethylenediaminetetraacetic acid (EDTA)-containing vaccine. Injected vaccine increased vascular leakage in mice, leading to systemic dissemination of vaccine components known to stimulate immune responses. Together, PF4/vaccine complex formation and the vaccine-stimulated proinflammatory milieu trigger a pronounced B-cell response that results in the formation of high-avidity anti-PF4 antibodies in VITT patients. The resulting high-titer anti-PF4 antibodies potently activated platelets in the presence of PF4 or DNA and polyphosphate polyanions. Anti-PF4 VITT patient antibodies also stimulated neutrophils to release neutrophil extracellular traps (NETs) in a platelet PF4-dependent manner. Biomarkers of procoagulant NETs were elevated in VITT patient serum, and NETs were visualized in abundance by immunohistochemistry in cerebral vein thrombi obtained from VITT patients. Together, vaccine-induced PF4/adenovirus aggregates and proinflammatory reactions stimulate pathologic anti-PF4 antibody production that drives thrombosis in VITT. The data support a 2-step mechanism underlying VITT that resembles the pathogenesis of (autoimmune) heparin-induced thrombocytopenia.
Assuntos
Complexo Antígeno-Anticorpo/imunologia , Autoanticorpos/imunologia , COVID-19/prevenção & controle , Proteínas do Capsídeo/efeitos adversos , ChAdOx1 nCoV-19/efeitos adversos , Contaminação de Medicamentos , Vetores Genéticos/efeitos adversos , Células HEK293/imunologia , Imunoglobulina G/imunologia , Fator Plaquetário 4/imunologia , Púrpura Trombocitopênica Idiopática/etiologia , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/efeitos adversos , Adenoviridae/imunologia , Animais , Complexo Antígeno-Anticorpo/ultraestrutura , Autoanticorpos/biossíntese , Síndrome de Vazamento Capilar/etiologia , Proteínas do Capsídeo/imunologia , Linhagem Celular Transformada , ChAdOx1 nCoV-19/química , ChAdOx1 nCoV-19/imunologia , ChAdOx1 nCoV-19/toxicidade , Difusão Dinâmica da Luz , Epitopos/química , Epitopos/imunologia , Armadilhas Extracelulares/imunologia , Extravasamento de Materiais Terapêuticos e Diagnósticos/etiologia , Vetores Genéticos/imunologia , Células HEK293/química , Humanos , Imageamento Tridimensional , Imunoglobulina G/biossíntese , Inflamação , Camundongos , Microscopia/métodos , Ativação Plaquetária , Proteômica , Púrpura Trombocitopênica Idiopática/sangue , Púrpura Trombocitopênica Idiopática/imunologia , Trombose dos Seios Intracranianos/diagnóstico por imagem , Trombose dos Seios Intracranianos/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Cultura de VírusRESUMO
PURPOSE OF REVIEW: This review describes the contribution of coagulation factor XII (FXII) in sterile inflammation and wound healing, focusing on recently identified roles for zymogen FXII in neutrophil functions. RECENT FINDINGS: Recent studies have identified an important role for FXII in neutrophil trafficking. In particular, following neutrophil activation, autocrine FXII signals through the urokinase plasminogen activator receptor (uPAR) on the neutrophil surface to upregulate neutrophil functions. The sum of these activities leads to neutrophil adhesion, chemotaxis, and neutrophil extracellular (NET) formation. Downregulating FXII-mediated signaling in neutrophils is associated with improved wound healing. SUMMARY: These recent findings show the sophisticated role of FXII in vivo and create new opportunities for research on the treatment of chronic inflammatory diseases.
Assuntos
Quimiotaxia/fisiologia , Fator XII/metabolismo , Ativação de Neutrófilo/fisiologia , Neutrófilos/metabolismo , Transdução de Sinais/fisiologia , Cicatrização/fisiologia , Adesão Celular/fisiologia , Armadilhas Extracelulares/metabolismo , Humanos , Inflamação/metabolismo , Ativador de Plasminogênio Tipo Uroquinase/metabolismoRESUMO
The precise mechanism for reduced thrombosis in prekallikrein null mice (Klkb1(-/-)) is unknown. Klkb1(-/-) mice have delayed carotid artery occlusion times on the rose bengal and ferric chloride thrombosis models. Klkb1(-/-) plasmas have long-activated partial thromboplastin times and defective contact activation-induced thrombin generation that partially corrects upon prolonged incubation. However, in contact activation-induced pulmonary thromboembolism by collagen/epinephrine or long-chain polyphosphate, Klkb1(-/-) mice, unlike F12(-/-) mice, do not have survival advantage. Klkb1(-/-) mice have reduced plasma BK levels and renal B2R mRNA. They also have increased expression of the renal receptor Mas and plasma prostacyclin. Increased prostacyclin is associated with elevated aortic vasculoprotective transcription factors Sirt1 and KLF4. Treatment of Klkb1(-/-) mice with the Mas antagonist A-779, COX-2 inhibitor nimesulide, or Sirt1 inhibitor splitomicin lowers plasma prostacyclin and normalizes arterial thrombosis times. Treatment of normal mice with the Mas agonist AVE0991 reduces thrombosis. Klkb1(-/-) mice have reduced aortic tissue factor (TF) mRNA, antigen, and activity. In sum, Klkb1(-/-) mice have a novel mechanism for thrombosis protection in addition to reduced contact activation. This pathway arises when bradykinin delivery to vasculature is compromised and mediated by increased receptor Mas, prostacyclin, Sirt1, and KLF4, leading to reduced vascular TF.
Assuntos
Trombose das Artérias Carótidas , Epoprostenol , Fatores de Transcrição Kruppel-Like , Pré-Calicreína , Proteínas Proto-Oncogênicas , Receptores Acoplados a Proteínas G , Tromboplastina , Angiotensina II/análogos & derivados , Angiotensina II/farmacologia , Animais , Trombose das Artérias Carótidas/induzido quimicamente , Trombose das Artérias Carótidas/genética , Trombose das Artérias Carótidas/metabolismo , Trombose das Artérias Carótidas/patologia , Epoprostenol/biossíntese , Epoprostenol/genética , Imidazóis/farmacologia , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/antagonistas & inibidores , Fatores de Transcrição Kruppel-Like/biossíntese , Fatores de Transcrição Kruppel-Like/genética , Camundongos , Camundongos Knockout , Naftalenos/farmacologia , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/genética , Tempo de Tromboplastina Parcial , Fragmentos de Peptídeos/farmacologia , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Pironas/farmacologia , RNA Mensageiro , Receptor B2 da Bradicinina/biossíntese , Receptor B2 da Bradicinina/genética , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Sirtuína 1/antagonistas & inibidores , Sirtuína 1/biossíntese , Sirtuína 1/genética , Sulfonamidas/farmacologia , Sinaptotagminas/biossíntese , Sinaptotagminas/genética , Tromboplastina/antagonistas & inibidores , Tromboplastina/biossíntese , Tromboplastina/genéticaRESUMO
Cancer is a leading cause of thrombosis. We identify a new procoagulant mechanism that contributes to thromboembolism in prostate cancer and allows for safe anticoagulation therapy development. Prostate cancer-mediated procoagulant activity was reduced in plasma in the absence of factor XII or its substrate of the intrinsic coagulation pathway factor XI. Prostate cancer cells and secreted prostasomes expose long chain polyphosphate on their surface that colocalized with active factor XII and initiated coagulation in a factor XII-dependent manner. Polyphosphate content correlated with the procoagulant activity of prostasomes. Inherited deficiency in factor XI or XII or high-molecular-weight kininogen, but not plasma kallikrein, protected mice from prostasome-induced lethal pulmonary embolism. Targeting polyphosphate or factor XII conferred resistance to prostate cancer-driven thrombosis in mice, without increasing bleeding. Inhibition of factor XII with recombinant 3F7 antibody reduced the increased prostasome-mediated procoagulant activity in patient plasma. The data illustrate a critical role for polyphosphate/factor XII-triggered coagulation in prostate cancer-associated thrombosis with implications for anticoagulation without therapy-associated bleeding in malignancies.
Assuntos
Fator XII/metabolismo , Polifosfatos/sangue , Neoplasias da Próstata/sangue , Neoplasias da Próstata/complicações , Trombose/sangue , Trombose/etiologia , Animais , Anticorpos Monoclonais Humanizados/administração & dosagem , Linhagem Celular Tumoral , Fator XIIa/antagonistas & inibidores , Fibrina/metabolismo , Humanos , Masculino , Camundongos , Embolia Pulmonar/sangue , Embolia Pulmonar/etiologia , Embolia Pulmonar/prevenção & controle , Vesículas Secretórias/metabolismo , Trombina/metabolismoRESUMO
BACKGROUND: Anaphylaxis is an acute, potentially lethal, multisystem syndrome resulting from the sudden release of mast cell-derived mediators into the circulation. OBJECTIVES AND METHODS: We report here that a plasma protease cascade, the factor XII-driven contact system, critically contributes to the pathogenesis of anaphylaxis in both murine models and human subjects. RESULTS: Deficiency in or pharmacologic inhibition of factor XII, plasma kallikrein, high-molecular-weight kininogen, or the bradykinin B2 receptor, but not the B1 receptor, largely attenuated allergen/IgE-mediated mast cell hyperresponsiveness in mice. Reconstitutions of factor XII null mice with human factor XII restored susceptibility for allergen/IgE-mediated hypotension. Activated mast cells systemically released heparin, which provided a negatively charged surface for factor XII autoactivation. Activated factor XII generates plasma kallikrein, which proteolyzes kininogen, leading to the liberation of bradykinin. We evaluated the contact system in patients with anaphylaxis. In all 10 plasma samples immunoblotting revealed activation of factor XII, plasma kallikrein, and kininogen during the acute phase of anaphylaxis but not at basal conditions or in healthy control subjects. The severity of anaphylaxis was associated with mast cell degranulation, increased plasma heparin levels, the intensity of contact system activation, and bradykinin formation. CONCLUSIONS: In summary, the data collectively show a role of the contact system in patients with anaphylaxis and support the hypothesis that targeting bradykinin generation and signaling provides a novel and alternative treatment strategy for anaphylactic attacks.
Assuntos
Anafilaxia/imunologia , Anafilaxia/metabolismo , Fator XII/metabolismo , Hipersensibilidade/imunologia , Hipersensibilidade/metabolismo , Mastócitos/imunologia , Adulto , Idoso , Anafilaxia/complicações , Anafilaxia/genética , Animais , Biomarcadores , Bradicinina/metabolismo , Modelos Animais de Doenças , Fator XII/antagonistas & inibidores , Fator XII/genética , Feminino , Humanos , Hipersensibilidade/complicações , Hipersensibilidade/genética , Hipotensão/etiologia , Cininogênios/metabolismo , Masculino , Camundongos Knockout , Pessoa de Meia-Idade , Receptor B2 da Bradicinina/genética , Receptor B2 da Bradicinina/metabolismo , Transdução de Sinais , Fatores de Tempo , Adulto JovemRESUMO
Prolylcarboxypeptidase (PRCP) is associated with leanness, hypertension, and thrombosis. PRCP-depleted mice have injured vessels with reduced Kruppel-like factor (KLF)2, KLF4, endothelial nitric oxide synthase (eNOS), and thrombomodulin. Does PRCP influence vessel growth, angiogenesis, and injury repair? PRCP depletion reduced endothelial cell growth, whereas transfection of hPRCP cDNA enhanced cell proliferation. Transfection of hPRCP cDNA, or an active site mutant (hPRCPmut) rescued reduced cell growth after PRCP siRNA knockdown. PRCP-depleted cells migrated less on scratch assay and murine PRCP(gt/gt) aortic segments had reduced sprouting. Matrigel plugs in PRCP(gt/gt) mice had reduced hemoglobin content and angiogenic capillaries by platelet endothelial cell adhesion molecule (PECAM) and NG2 immunohistochemistry. Skin wounds on PRCP(gt/gt) mice had delayed closure and reepithelialization with reduced PECAM staining, but increased macrophage infiltration. After limb ischemia, PRCP(gt/gt) mice also had reduced reperfusion of the femoral artery and angiogenesis. On femoral artery wire injury, PRCP(gt/gt) mice had increased neointimal formation, CD45 staining, and Ki-67 expression. Alternatively, combined PRCP(gt/gt) and MRP-14(-/-) mice were protected from wire injury with less neointimal thickening, leukocyte infiltration, and cellular proliferation. PRCP regulates cell growth, angiogenesis, and the response to vascular injury. Combined with its known roles in blood pressure and thrombosis control, PRCP is positioned as a key regulator of vascular homeostasis.
Assuntos
Carboxipeptidases/fisiologia , Células Endoteliais/enzimologia , Neovascularização Patológica , Neovascularização Fisiológica , Animais , Aorta/metabolismo , Apoptose , Calgranulina B/metabolismo , Bovinos , Movimento Celular , Proliferação de Células , Células Cultivadas , Artéria Femoral/patologia , Células Endoteliais da Veia Umbilical Humana , Humanos , Isquemia/patologia , Antígeno Ki-67/metabolismo , Fator 4 Semelhante a Kruppel , Camundongos , Camundongos Endogâmicos C57BL , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , CicatrizaçãoRESUMO
Bradykinin B2 receptor-deleted mice (Bdkrb2(-/-)) have delayed carotid artery thrombosis times and prolonged tail bleeding time resulting from elevated angiotensin II (AngII) and angiotensin receptor 2 (AT2R) producing increased plasma nitric oxide (NO) and prostacyclin. Bdkrb2(-/-) also have elevated plasma angiotensin-(1-7) and messenger RNA and protein for its receptor Mas. Blockade of Mas with its antagonist A-779 in Bdkrb2(-/-) shortens thrombosis times (58 ± 4 minutes to 38 ± 4 minutes) and bleeding times (170 ± 13 seconds to 88 ± 8 seconds) and lowers plasma nitrate (22 ± 4 µM to 15 ± 5 µM), and 6-keto-PGF1α (259 ± 103 pg/mL to 132 ± 58 pg/mL). Bdkrb2(-/-) platelets express increased NO, guanosine 3',5'-cyclic monophosphate, and cyclic adenosine monophosphate with reduced spreading on collagen, collagen peptide GFOGER, or fibrinogen. In vivo A-779 or combined L-NAME and nimesulide treatment corrects it. Bdkrb2(-/-) platelets have reduced collagen-related peptide-induced integrin α2bß3 activation and P-selectin expression that are partially corrected by in vivo A-779, nimesulide, or L-NAME. Bone marrow transplantations show that the platelet phenotype and thrombosis time depends on the host rather than donor bone marrow progenitors. Transplantation of wild-type bone marrow into Bdkrb2(-/-) hosts produces platelets with a spreading defect and delayed thrombosis times. In Bdkrb2(-/-), combined AT2R and Mas overexpression produce elevated plasma prostacyclin and NO leading to acquired platelet function defects and thrombosis delay.
Assuntos
Angiotensina I/sangue , Plaquetas/metabolismo , Epoprostenol/sangue , Óxido Nítrico/sangue , Fragmentos de Peptídeos/sangue , Glicoproteínas da Membrana de Plaquetas/metabolismo , Proteínas Proto-Oncogênicas/sangue , Receptores Acoplados a Proteínas G/sangue , Angiotensina II/análogos & derivados , Angiotensina II/farmacologia , Animais , Tempo de Sangramento , Plaquetas/efeitos dos fármacos , Transplante de Medula Óssea , AMP Cíclico/sangue , GMP Cíclico/sangue , Immunoblotting , Camundongos , Camundongos da Linhagem 129 , Camundongos Knockout , NG-Nitroarginina Metil Éster/farmacologia , Fragmentos de Peptídeos/farmacologia , Inibidores da Agregação Plaquetária/farmacologia , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/genética , Receptor Tipo 2 de Angiotensina/sangue , Receptor B2 da Bradicinina/deficiência , Receptor B2 da Bradicinina/genética , Receptores Acoplados a Proteínas G/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sulfonamidas/farmacologia , Trombose/sangue , Fatores de TempoRESUMO
The University of North Carolina Symposia on Hemostasis began in 2002, with The First Symposium on Hemostasis with a Special Focus on FVIIa and Tissue Factor. They have occurred biannually since and have maintained the primary goal of establishing a forum for the sharing of outstanding advances made in the basic sciences of hemostasis. The 2024 11th Symposium on Hemostasis will bring together leading scientists from around the globe to present and discuss the latest research related to coagulation factors and platelet biology. In keeping with the tradition of the conference, we expect novel cross-disciplinary collaborations to result from bringing together fundamental scientists and physician-scientists from different backgrounds and perspectives. The aim of these collaborations is to springboard the next generation of important advances in the field. This year's program was designed to discuss Coagulation and Platelet Biology at the Intersection of Health and Disease. The goal is to develop a better understanding of the pathophysiologic mechanisms leading to hemostatic and thrombotic disorders as this understanding is critical for the continued development of safe and efficacious therapeutics. Included in this review article are illustrated capsules provided by our speakers that highlight the main conclusions of the invited talks.
RESUMO
Prolylcarboxypeptidase (PRCP) activates prekallikrein to plasma kallikrein, leading to bradykinin liberation, and degrades angiotensin II. We now identify PRCP as a regulator of blood vessel homeostasis. ß-Galactosidase staining in PRCP(gt/gt) mice reveals expression in kidney and vasculature. Invasive telemetric monitorings show that PRCP(gt/gt) mice have significantly elevated blood pressure. PRCP(gt/gt) mice demonstrate shorter carotid artery occlusion times in 2 models, and their plasmas have increased thrombin generation times. Pharmacologic inhibition of PRCP with Z-Pro-Prolinal or plasma kallikrein with soybean trypsin inhibitor, Pro-Phe-Arg-chloromethylketone or PKSI 527 also shortens carotid artery occlusion times. Aortic and renal tissues have uncoupled eNOS and increased reactive oxygen species (ROS) in PRCP(gt/gt) mice as detected by dihydroethidium or Amplex Red fluorescence or lucigenin luminescence. The importance of ROS is evidenced by the fact that treatment of PRCP(gt/gt) mice with antioxidants (mitoTEMPO, apocynin, Tempol) abrogates the hypertensive, prothrombotic phenotype. Mechanistically, our studies reveal that PRCP(gt/gt) aortas express reduced levels of Kruppel-like factors 2 and 4, thrombomodulin, and eNOS mRNA, suggesting endothelial cell dysfunction. Further, PRCP siRNA treatment of endothelial cells shows increased ROS and uncoupled eNOS and decreased protein C activation because of thrombomodulin inactivation. Collectively, our studies identify PRCP as a novel regulator of vascular ROS and homeostasis.
Assuntos
Carboxipeptidases/genética , Trombose das Artérias Carótidas/genética , Hipertensão/genética , Interferência de RNA/fisiologia , Doenças Vasculares/genética , Animais , Vasos Sanguíneos/efeitos dos fármacos , Vasos Sanguíneos/metabolismo , Vasos Sanguíneos/fisiopatologia , Carboxipeptidases/antagonistas & inibidores , Carboxipeptidases/fisiologia , Trombose das Artérias Carótidas/complicações , Células Cultivadas , Técnicas de Silenciamento de Genes , Humanos , Hipertensão/complicações , Hipertensão/fisiopatologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , RNA Interferente Pequeno/farmacologia , Tempo de Trombina , Fatores de Tempo , Doenças Vasculares/complicações , Doenças Vasculares/fisiopatologiaRESUMO
Gender-affirming hormonal therapies are a critical component of the care of transgender individuals. Transgender people are commonly prescribed estrogen or testosterone to promote male-to-female or female-to-male transitions and to preserve gender-specific characteristics long-term. However, some exogenous hormones, especially certain estrogen preparations, are an established risk factor of thrombosis. As the number of individuals seeking gender-based care is rising, there is an urgent need to identify and characterize the mechanisms underlying hormone-associated thrombosis and incorporate this information into clinical algorithms for diagnosis and management. Herein, we discuss historical evidence on the incidence of thrombosis and changes in plasma composition in transgender and cisgender cohorts. We present 3 case studies to demonstrate knowledge gaps in thrombosis risk stratification and prediction tools. We also present data from in vitro coagulation and fibrinolysis assays and discuss how information from these kinds of assays may be used to help guide the clinical management of transgender individuals.
RESUMO
Neutrophil recruitment to the inflamed endothelium is a multistep process and is of utmost importance in the development of the hallmark vaso-occlusive crisis in sickle cell disease (SCD). However, there lacks a standardized, clinically feasible approach for assessing neutrophil recruitment to the inflamed endothelium for individualized risk stratification and therapeutic response prediction in SCD. Here, we describe a microfluidic device functionalized with E-selectin, a critical endothelial receptor for the neutrophil recruitment process, as a strategy to assess neutrophil binding under physiologic flow in normoxia and clinically relevant hypoxia in SCD. We show that hypoxia significantly enhances neutrophil binding to E-selectin and promotes the formation of neutrophil-platelet aggregates. Moreover, we identified two distinct patient populations: a more severe clinical phenotype with elevated lactate dehydrogenase levels and absolute reticulocyte counts but lowered fetal hemoglobin levels associated with constitutively less neutrophil binding to E-selectin. Mechanistically, we demonstrate that the extent of neutrophil activation correlates with membrane L-selectin shedding, resulting in the loss of ligand interaction sites with E-selectin. We also show that inhibition of E-selectin significantly reduces leukocyte recruitment to activated endothelial cells. Our findings add mechanistic insight into neutrophil-endothelial interactions under hypoxia and provide a clinically feasible means for assessing neutrophil binding to E-selectin using clinical whole blood samples, which can help guide therapeutic decisions for SCD patients.
Assuntos
Anemia Falciforme , Técnicas Biossensoriais , Humanos , Selectina E/uso terapêutico , Células Endoteliais/metabolismo , Infiltração de Neutrófilos , Adesão Celular , Endotélio/metabolismo , Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/metabolismo , Dispositivos Lab-On-A-Chip , HipóxiaRESUMO
BACKGROUND: Human serum albumin (HSA) is the most abundant plasma protein and is sensitive to glycation in vivo. The chronic hyperglycemic conditions in patients with diabetes mellitus (DM) induce a nonenzymatic Maillard reaction that denatures plasma proteins and forms advanced glycation end products (AGEs). HSA-AGE is a prevalent misfolded protein in patients with DM and is associated with factor XII activation and downstream proinflammatory kallikrein-kinin system activity without any associated procoagulant activity of the intrinsic pathway. OBJECTIVES: This study aimed to determine the relevance of HSA-AGE toward diabetic pathophysiology. METHODS: The plasma obtained from patients with DM and euglycemic volunteers was probed for activation of FXII, prekallikrein (PK), and cleaved high-molecular-weight kininogen by immunoblotting. Constitutive plasma kallikrein activity was determined via chromogenic assay. Activation and kinetic modulation of FXII, PK, FXI, FIX, and FX via in vitro-generated HSA-AGE were explored using chromogenic assays, plasma-clotting assays, and an in vitro flow model using whole blood. RESULTS: Plasma obtained from patients with DM contained increased plasma AGEs, activated FXIIa, and resultant cleaved cleaved high-molecular-weight kininogen. Elevated constitutive plasma kallikrein enzymatic activity was identified, which positively correlated with glycated hemoglobin levels, representing the first evidence of this phenomenon. HSA-AGE, generated in vitro, triggered FXIIa-dependent PK activation but limited the intrinsic coagulation pathway activation by inhibiting FXIa and FIXa-dependent FX activation in plasma. CONCLUSION: These data indicate a proinflammatory role of HSA-AGEs in the pathophysiology of DM via FXII and kallikrein-kinin system activation. A procoagulant effect of FXII activation was lost through the inhibition of FXIa and FIXa-dependent FX activation by HSA-AGEs.
Assuntos
Calicreínas , Calicreína Plasmática , Humanos , Calicreínas/metabolismo , Calicreína Plasmática/metabolismo , Cininas , Fator XIIa/metabolismo , Cininogênio de Alto Peso Molecular/metabolismo , Pré-Calicreína/metabolismo , Albuminas , Produtos Finais de Glicação AvançadaRESUMO
Background: Neutrophil Extracellular Traps (NETs) are key mediators of immunothrombotic mechanisms and defective clearance of NETs from the circulation underlies an array of thrombotic, inflammatory, infectious, and autoimmune diseases. Efficient NET degradation depends on the combined activity of two distinct DNases, DNase1 and DNase1-like 3 (DNase1L3) that preferentially digest double-stranded DNA (dsDNA) and chromatin, respectively. Methods: Here, we engineered a dual-active DNase with combined DNase1 and DNase1L3 activities and characterized the enzyme for its NET degrading potential in vitro. Furthermore, we produced a mouse model with transgenic expression of the dual-active DNase and analyzed body fluids of these animals for DNase1 and DNase 1L3 activities. We systematically substituted 20 amino acid stretches in DNase1 that were not conserved among DNase1 and DNase1L3 with homologous DNase1L3 sequences. Results: We found that the ability of DNase1L3 to degrade chromatin is embedded into three discrete areas of the enzyme's core body, not the C-terminal domain as suggested by the state-of-the-art. Further, combined transfer of the aforementioned areas of DNase1L3 to DNase1 generated a dual-active DNase1 enzyme with additional chromatin degrading activity. The dual-active DNase1 mutant was superior to native DNase1 and DNase1L3 in degrading dsDNA and chromatin, respectively. Transgenic expression of the dual-active DNase1 mutant in hepatocytes of mice lacking endogenous DNases revealed that the engineered enzyme was stable in the circulation, released into serum and filtered to the bile but not into the urine. Conclusion: Therefore, the dual-active DNase1 mutant is a promising tool for neutralization of DNA and NETs with potential therapeutic applications for interference with thromboinflammatory disease states.
Assuntos
Endodesoxirribonucleases , Armadilhas Extracelulares , Camundongos , Animais , Endodesoxirribonucleases/genética , Armadilhas Extracelulares/metabolismo , Desoxirribonuclease I/genética , Desoxirribonuclease I/metabolismo , Cromatina , DNA/metabolismo , Desoxirribonucleases/genéticaRESUMO
Targeted drug delivery to disease-associated activated neutrophils can provide novel therapeutic opportunities while avoiding systemic effects on immune functions. We created a nanomedicine platform that uniquely utilizes an α1-antitrypsin-derived peptide to confer binding specificity to neutrophil elastase on activated neutrophils. Surface decoration with this peptide enabled specific anchorage of nanoparticles to activated neutrophils and platelet-neutrophil aggregates, in vitro and in vivo. Nanoparticle delivery of a model drug, hydroxychloroquine, demonstrated significant reduction of neutrophil activities in vitro and a therapeutic effect on murine venous thrombosis in vivo. This innovative approach of cell-specific and activation-state-specific targeting can be applied to several neutrophil-driven pathologies.
Assuntos
Elastase de Leucócito , Deficiência de alfa 1-Antitripsina , Animais , Humanos , Hidroxicloroquina/farmacologia , Elastase de Leucócito/metabolismo , Camundongos , Nanomedicina , NeutrófilosRESUMO
BACKGROUND: Resilience is a person's mental ability to deal with challenging situations adaptively and is a crucial stress management skill. Psychological resilience and finding ways to cope in crises is a highly relevant topic considering the COVID-19 pandemic, which enforced quarantine, social distancing measures, and school closures worldwide. Parents and children are currently living with increased stress due to COVID-19. We need to respond with immediate ways to strengthen children's resilience. Internet-based cognitive behavioral therapy interventions for children's stress management overcome accessibility issues such as the inability to visit mental health experts owing to COVID-19 movement restrictions. An interactive learning environment was created, based on the preventive program "Friends," to overcome accessibility issues associated with delivering cognitive behavioral therapy-based interventions in formal and informal education settings. OBJECTIVE: This study aimed to examine the effectiveness of a web-based learning environment on resilience in (1) reducing anxiety symptoms and (2) increasing emotion recognition and recognition of stress management techniques among 9-10-year-old children. We also aimed to evaluate the learning environment's usability. METHODS: A quasi-experimental pretest-posttest control group design was used. In total, 20 fourth graders in the experimental group interacted with the learning environment over 6 weekly 80-minute sessions. Further, 21 fourth graders constituted the control group. The main data sources were (1) a psychometric tool to measure children's anxiety symptoms, namely the Greek translation of the original Spence Children's Anxiety Scale, (2) 3 open-ended questions assessing emotion recognition and recognition of stress management techniques, and (3) the System Usability Scale to measure the usability of the learning environment. RESULTS: In both groups, there was a small but nonsignificant postintervention reduction in reported anxiety symptoms, except for obsessive-compulsive disorder symptoms in the experimental group. A paired samples t test revealed that students' reported symptom scores of obsessive-compulsive disorder significantly decreased from 1.06 (SD 0.68) to 0.76 (SD 0.61) (t19= 5.16; P=.01). The experimental group revealed a significant increase in emotion recognition (t19=-6.99; P<.001), identification of somatic symptoms of stress (t19=-7.31; P<.001), and identification of stress management techniques (t19=-6.85; P<.001). The learning environment received a satisfactory usability score. The raw average system usability score was 76.75 (SD 8.28), which is in the 80th percentile rank and corresponds to grade B. CONCLUSIONS: This study shows that interactive learning environments might deliver resilience interventions in an accessible and cost-effective manner in formal education, potentially even in distance-learning conditions owing to the COVID-19 pandemic. Interactive learning environments on resilience are also valuable tools for parents who can use them with their children at home, for informal learning, using mobile devices. As such, they could be a promising first-step, low-intensity intervention that children and the youth can easily access.
RESUMO
BACKGROUND: There are acute settings where assessing the anticoagulant effect of direct oral anticoagulants (DOACs) can be useful. Due to variability among routine coagulation tests, there is an unmet need for an assay that detects DOAC effects within minutes in the laboratory or at the point of care. METHODS: We developed a novel dielectric microsensor, termed ClotChip, and previously showed that the time to reach peak permittivity (T peak) is a sensitive parameter of coagulation function. We conducted a prospective, single-center, pilot study to determine its clinical utility at detecting DOAC anticoagulant effects in whole blood. RESULTS: We accrued 154 individuals: 50 healthy volunteers, 49 rivaroxaban patients, 47 apixaban, and 8 dabigatran patients. Blood samples underwent ClotChip measurements and plasma coagulation tests. Control mean T peak was 428 seconds (95% confidence interval [CI]: 401-455 seconds). For rivaroxaban, mean T peak was 592 seconds (95% CI: 550-634 seconds). A receiver operating characteristic curve showed that the area under the curve (AUC) predicting rivaroxaban using T peak was 0.83 (95% CI: 0.75-0.91, p < 0.01). For apixaban, mean T peak was 594 seconds (95% CI: 548-639 seconds); AUC was 0.82 (95% CI: 0.73-0.91, p < 0.01). For dabigatran, mean T peak was 894 seconds (95% CI: 701-1,086 seconds); AUC was 1 (p < 0.01). Specificity for all DOACs was 88%; sensitivity ranged from 72 to 100%. CONCLUSION: This diagnostic study using samples from "real-world" DOAC patients supports that ClotChip exhibits high sensitivity at detecting DOAC anticoagulant effects in a disposable portable platform, using a miniscule amount of whole blood (<10 µL).
Assuntos
Testes de Coagulação Sanguínea/instrumentação , Monitoramento de Medicamentos/instrumentação , Inibidores do Fator Xa/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Coagulação Sanguínea/efeitos dos fármacos , Testes de Coagulação Sanguínea/métodos , Dabigatrana/farmacologia , Dabigatrana/uso terapêutico , Monitoramento de Medicamentos/métodos , Desenho de Equipamento , Inibidores do Fator Xa/farmacologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pirazóis/farmacologia , Pirazóis/uso terapêutico , Piridonas/farmacologia , Piridonas/uso terapêutico , Rivaroxabana/farmacologia , Rivaroxabana/uso terapêuticoRESUMO
BACKGROUND: Coagulopathy and inflammation are hallmarks of Coronavirus disease 2019 (COVID-19) and are associated with increased mortality. Clinical and experimental data have revealed a role for neutrophil extracellular traps (NETs) in COVID-19 disease. The mechanisms that drive thrombo-inflammation in COVID-19 are poorly understood. METHODS: We performed proteomic analysis and immunostaining of postmortem lung tissues from COVID-19 patients and patients with other lung pathologies. We further compared coagulation factor XII (FXII) and DNase activities in plasma samples from COVID-19 patients and healthy control donors and determined NET-induced FXII activation using a chromogenic substrate assay. FINDINGS: FXII expression and activity were increased in the lung parenchyma, within the pulmonary vasculature and in fibrin-rich alveolar spaces of postmortem lung tissues from COVID-19 patients. In agreement with this, plasmaaac acafajföeFXII activation (FXIIa) was increased in samples from COVID-19 patients. Furthermore, FXIIa colocalized with NETs in COVID-19 lung tissue indicating that NETs accumulation leads to FXII contact activation in COVID-19. We further showed that an accumulation of NETs is partially due to impaired NET clearance by extracellular DNases as DNase substitution improved NET dissolution and reduced FXII activation in vitro. INTERPRETATION: Collectively, our study supports that the NET/FXII axis contributes to the pathogenic chain of procoagulant and proinflammatory responses in COVID-19. Targeting both NETs and FXIIa may offer a potential novel therapeutic strategy. FUNDING: This study was supported by the European Union (840189), the Werner Otto Medical Foundation Hamburg (8/95) and the German Research Foundation (FR4239/1-1, A11/SFB877, B08/SFB841 and P06/KFO306).