Project description:Arterial and venous (A/V) thrombosis constitutes the greatest source of morbidity and mortality worldwide. Long considered as distinct entities, accumulating evidence indicates that A/V thrombosis can occur in the same populations suggesting that common mechanisms are likely operative. Although hyperactivation of the immune system is a common forerunner to the genesis of thrombotic events in both vascular systems, the key molecular control points remain poorly understood. Consequently, anti-thrombotic therapies targeting the immune system for therapeutic gain are lacking. Here we show that neutrophils are key effectors of both A/V thrombosis and can be targeted via novel immunoregulatory nanoparticles. Using antiphopholipid antibody syndrome (APS) as a model for devastating A/V thrombosis, we identified the transcription factor Krüppel-like factor 2 (KLF2) as a key regulator of neutrophil activation. Upon activation via genetic loss of KLF2 or administration of antiphospholipid antibodies, neutrophils cluster P-selectin glycoprotein ligand 1 (PSGL-1) via cortical actin remodeling, thereby increasing adhesion potential at thrombosis sites. Targeting clustered PSGL-1 using designer nanoparticles attenuates neutrophil-mediated A/V thrombosis in APS and KLF2 knockout models, illustrating the importance and feasibility of targeting activated neutrophils to prevent pathological thrombosis. Together, our results demosntrate a role for activated neutrophils to prevent pathological thrombosis. Together, our results demonstrate a role for activated neutorphils in both arterial and venous thrombosis and identify key molecular events that serve as potential targets for therapeutics against diverse causes of immunothrombosis.
Project description:Protein C (PC) deficiency increases the risk of venous thrombosis (VT) among members of Kindred Vermont II, but fails to fully account for the inheritance pattern. A genome scan of the pedigree supported the presence of a prothrombotic gene on chromosome 11q23 with weaker support on chromosomes 10p12 and 18p11.2-q11. Preliminary data from Affimetrix microarray expression analysis of Blood Outgrowth Endothelial Cells of 3 members of Kindred Vermont II compared to a well established normal control group indicated that IgsF4 was decreased in patients versus controls. In addition, both statistical and pathway analysis results suggested that these genes are associated protein C. Further studies indicated that Cell Adhesion Molecule 1 (CADM1), a member of the IgsF4 superfamily, may be associated with VT. Experiment Overall Design: We obtained BOEC (blood outgrowth endothelial cells) from 3 female kindred subjects (ages 56, 61, and 74) with Protein C Deficiency. We also performed microarray analysis on BOEC from 27 normal subjects of diverse ages.
Project description:Protein C (PC) deficiency increases the risk of venous thrombosis (VT) among members of Kindred Vermont II, but fails to fully account for the inheritance pattern. A genome scan of the pedigree supported the presence of a prothrombotic gene on chromosome 11q23 with weaker support on chromosomes 10p12 and 18p11.2-q11. Preliminary data from Affimetrix microarray expression analysis of Blood Outgrowth Endothelial Cells of 3 members of Kindred Vermont II compared to a well established normal control group indicated that IgsF4 was decreased in patients versus controls. In addition, both statistical and pathway analysis results suggested that these genes are associated protein C. Further studies indicated that Cell Adhesion Molecule 1 (CADM1), a member of the IgsF4 superfamily, may be associated with VT.
Project description:Coagulopathy is a hallmark finding in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is associated with an increased risk of death from venous and arterial thromboembolic complications. SARS-CoV-2 infection can lead to microvascular thrombosis that contributes to acute lung injury and respiratory failure. The molecular mechanisms leading to thrombosis in Coronavirus disease 2019 (COVID19) patients are poorly understood. Here, we study a role of the procoagulant neutrophil extracellular traps (NETs)/Factor XII (FXII) axis in COVID19-associated thromboembolism.
Project description:Coagulopathy is a hallmark finding in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is associated with an increased risk of death from venous and arterial thromboembolic complications. SARS-CoV-2 infection can lead to microvascular thrombosis that contributes to acute lung injury and respiratory failure. The molecular mechanisms leading to thrombosis in Coronavirus disease 2019 (COVID19) patients are poorly understood. Here, we study a role of the procoagulant neutrophil extracellular traps (NETs)/Factor XII (FXII) axis in COVID19-associated thromboembolism.
Project description:Cancer patients often have an activated clotting system and are at increased risk for venous thrombosis. In this study, we analyzed tissue factor (TF) expression in four different human pancreatic tumor cell lines for the purpose of producing derivative tumors in vivo. We found that two of the lines expressed TF and released TF-positive microparticles (MPs) into the culture medium. The majority of TF protein in the culture medium was associated with MPs. Importantly, only TF-positive cell lines activated coagulation in nude mice, and this activation was abolished by an anti-human TF antibody. Of the two TF-positive lines only one produced detectable levels of human MP TF activity in the plasma when grown orthotopically in nude mice. Surprisingly, <5% of human TF protein in plasma from tumor-bearing mice was associated with MPs. Mice with TF-positive tumors and elevated levels of circulating TF-positive MPs had increased thrombosis in a saphenous vein model. In contrast, we observed no difference in thrombus weight between tumor bearing and control mice in an inferior vena cava stenosis model. Our studies suggest that in a xenograft mouse model tumor TF activates coagulation, whereas TF on circulating MPs may trigger venous thrombosis.
Project description:Deep vein thrombosis (DVT) is a common clinical problem, but its cellular and molecular mechanisms remain incompletely understood. We performed single-cell RNA sequencing (scRNA-seq) on the vein wall of mouse inferior vena cava (IVC) ligation model of deep vein thrombosis (DVT), to analyze the transcriptomic changes in the vein wall during acute venous thrombosis.
Project description:Leukocyte flux contributes to thrombus formation in deep veins under pathologic conditions, but mechanisms which inhibit venous thrombosis are incompletely understood. Ectonucleotide di(tri)phosphohydrolase 1 (ENTPD1 or Cd39), an ectoenzyme which catabolizes extracellular adenine nucleotides, is embedded on the surface of endothelial cells and leukocytes. We hypothesized that under venous stasis conditions CD39 regulates inflammation at the vein:blood interface in a murine model of deep vein thrombosis. Gene expression profiling of WT and Cd39-null mice revealed 76 differentially-expressed inflammatory genes that were significantly upregulated in Cd39-deleted mice after venous thrombosis; and validation experiments confirmed high expression of several key inflammatory mediators.