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Arteriosclerosis, Thrombosis, and... Jul 2023Antithrombin, PC (protein C), and PS (protein S) are circulating natural anticoagulant proteins that regulate hemostasis and of which partial deficiencies are causes of...
BACKGROUND
Antithrombin, PC (protein C), and PS (protein S) are circulating natural anticoagulant proteins that regulate hemostasis and of which partial deficiencies are causes of venous thromboembolism. Previous genetic association studies involving antithrombin, PC, and PS were limited by modest sample sizes or by being restricted to candidate genes. In the setting of the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium, we meta-analyzed across ancestries the results from 10 genome-wide association studies of plasma levels of antithrombin, PC, PS free, and PS total.
METHODS
Study participants were of European and African ancestries, and genotype data were imputed to TOPMed, a dense multiancestry reference panel. Each of the 10 studies conducted a genome-wide association studies for each phenotype and summary results were meta-analyzed, stratified by ancestry. Analysis of antithrombin included 25 243 European ancestry and 2688 African ancestry participants, PC analysis included 16 597 European ancestry and 2688 African ancestry participants, PSF and PST analysis included 4113 and 6409 European ancestry participants. We also conducted transcriptome-wide association analyses and multiphenotype analysis to discover additional associations. Novel genome-wide association studies and transcriptome-wide association analyses findings were validated by in vitro functional experiments. Mendelian randomization was performed to assess the causal relationship between these proteins and cardiovascular outcomes.
RESULTS
Genome-wide association studies meta-analyses identified 4 newly associated loci: 3 with antithrombin levels (, , and ) and 1 with PS levels (-). transcriptome-wide association analyses identified 3 newly associated genes: 1 with antithrombin level (), 1 with PC (), and 1 with PS (). In addition, we replicated 7 independent loci reported in previous studies. Functional experiments provided evidence for the involvement of , , and genes in antithrombin regulation.
CONCLUSIONS
The use of larger sample sizes, diverse populations, and a denser imputation reference panel allowed the detection of 7 novel genomic loci associated with plasma antithrombin, PC, and PS levels.
Topics: Protein C; Protein S; Genome-Wide Association Study; Antithrombins; Transcriptome; Anticoagulants; Antithrombin III; Polymorphism, Single Nucleotide
PubMed: 37128921
DOI: 10.1161/ATVBAHA.122.318213 -
Blood Apr 2023
Topics: Antithrombins; Factor IXa; Antithrombin III; Anticoagulants
PubMed: 37079331
DOI: 10.1182/blood.2023019793 -
Antithrombin Activity and Association with Risk of Thrombosis and Mortality in Patients with Cancer.International Journal of Molecular... Dec 2022Venous and arterial thromboembolism (VTE/ATE) are common complications in cancer patients. Antithrombin deficiency is a risk factor for thrombosis in the general... (Observational Study)
Observational Study
Venous and arterial thromboembolism (VTE/ATE) are common complications in cancer patients. Antithrombin deficiency is a risk factor for thrombosis in the general population, but its connection to risk of cancer-associated thrombosis is unclear. We investigated the association of antithrombin activity levels with risk of cancer-associated VTE/ATE and all-cause mortality in an observational cohort study including patients with cancer, the Vienna Cancer and Thrombosis Study. In total, 1127 patients were included (45% female, median age: 62 years). Amongst these subjects, 110 (9.7%) patients were diagnosed with VTE, 32 (2.8%) with ATE, and 563 (49.9%) died. Antithrombin was not associated with a risk of VTE (subdistribution hazard ratio (SHR): 1.00 per 1% increase in antithrombin level; 95% CI: 0.99-1.01) or ATE (SHR: 1.00; 95% CI: 0.98-1.03). However, antithrombin showed a u-shaped association with the risk of all-cause death, i.e., patients with very low but also very high levels had poorer overall survival. In the subgroup of patients with brain tumors, higher antithrombin levels were associated with ATE risk (SHR: 1.02 per 1% increase; 95% CI: 1.00-1.04) and mortality (HR: 1.01 per 1% increase; 95% CI: 1.00-1.02). Both high and low antithrombin activity was associated with the risk of death. However, no association with cancer-associated VTE and ATE across all cancer types was found, with the exception of in brain tumors.
Topics: Humans; Female; Middle Aged; Male; Antithrombins; Venous Thromboembolism; Antithrombin III; Thrombosis; Risk Factors; Brain Neoplasms
PubMed: 36555414
DOI: 10.3390/ijms232415770 -
Journal of Thrombosis and Haemostasis :... Dec 2020Antithrombin (AT) is a major plasma glycoprotein of the serpin superfamily that regulates the proteolytic activity of the procoagulant proteases of both intrinsic and... (Review)
Review
Antithrombin (AT) is a major plasma glycoprotein of the serpin superfamily that regulates the proteolytic activity of the procoagulant proteases of both intrinsic and extrinsic pathways. Two important structural features that participate in the regulatory function of AT include a mobile reactive center loop that binds to active site of coagulation proteases, trapping them in the form of inactive covalent complexes, and a basic D-helix that binds to therapeutic heparins and heparan sulfate proteoglycans (HSPGs) on vascular endothelial cells. The binding of D-helix of AT by therapeutic heparins promotes the reactivity of the serpin with coagulation proteases by several orders of magnitude by both a conformational activation of the serpin and a template (bridging) mechanism. In addition to its essential anticoagulant function, AT elicits a potent anti-inflammatory signaling response when it binds to distinct vascular endothelial cell HSPGs, thereby inducing prostacyclin synthesis. Syndecans-4 has been found as a specific membrane-bound HSPG receptor on endothelial cells that relays the signaling effect of AT to the relevant second messenger molecules in the signal transduction pathways inside the cell. However, following cleavage by coagulation proteases and/or by spontaneous conversion to a latent form, AT loses both its anti-inflammatory activity and high-affinity interaction with heparin and HSPGs. Interestingly, these low-affinity heparin conformers of AT elicit potent proapoptotic and antiangiogenic activities by also binding to specific HSPGs by unknown mechanisms. This review article will summarize current knowledge about mechanisms through which different conformers of AT exert their serine protease inhibitory and intracellular signaling functions in these biological pathways.
Topics: Anticoagulants; Antithrombin III; Antithrombins; Endothelial Cells; Heparin; Signal Transduction
PubMed: 32780936
DOI: 10.1111/jth.15052 -
Clinical and Applied... 2023Antithrombin (AT) is a natural anticoagulant pivotal in inactivating serine protease enzymes in the coagulation cascade, making it a potent inhibitor of blood clot...
Antithrombin (AT) is a natural anticoagulant pivotal in inactivating serine protease enzymes in the coagulation cascade, making it a potent inhibitor of blood clot formation. AT also possesses anti-inflammatory properties by influencing anticoagulation and directly interacting with endothelial cells. Hereditary AT deficiency is one of the most severe inherited thrombophilias, with up to 85% lifetime risk of venous thromboembolism. Acquired AT deficiency arises during heparin therapy or states of hypercoagulability like sepsis and premature infancy. Optimization of AT levels in individuals with AT deficiency is an important treatment consideration, particularly during high-risk situations such as surgery, trauma, pregnancy, and postpartum. Here, we integrate the existing evidence surrounding the approved uses of AT therapy, as well as potential additional patient populations where AT therapy has been considered by the medical community, including any available consensus statements and guidelines. We also describe current knowledge regarding cost-effectiveness of AT concentrate in different contexts. Future work should seek to identify specific patient populations for whom targeted AT therapy is likely to provide the strongest clinical benefit.
Topics: Pregnancy; Female; Humans; Antithrombins; Endothelial Cells; Anticoagulants; Antithrombin III; Blood Coagulation; Antithrombin III Deficiency
PubMed: 37822179
DOI: 10.1177/10760296231205279 -
Blood Jul 2022
Topics: Antithrombin III; Antithrombin III Deficiency; Antithrombins; Glycosylation; Humans; Sugars; Thrombophilia
PubMed: 35834281
DOI: 10.1182/blood.2022016677 -
Clinical Science (London, England :... May 2017The gene encodes a serine protease inhibitor named antithrombin III (ATIII). This protease demonstrates both anticoagulant and anti-inflammatory action. ATIII is the... (Review)
Review
The gene encodes a serine protease inhibitor named antithrombin III (ATIII). This protease demonstrates both anticoagulant and anti-inflammatory action. ATIII is the most important coagulation factor inhibitor, and even minor changes in ATIII can significantly alter the risk of thromboembolism. ATIII can also suppress inflammation via a coagulation-dependent or -independent effect. Moreover, apart from ATIII deficiency, ATIII and its gene may also be related to many diseases (e.g. hypertension, kidney diseases). The present review summarizes how ATIII affects the progress of kidney disease and its mechanism. Further studies are required to investigate how ATIII affects renal function and the treatment.
Topics: Antithrombin III; Antithrombin III Deficiency; Blood Coagulation; Humans; Inflammation; Kidney Diseases; Models, Biological; Risk Factors; Signal Transduction; Thromboembolism
PubMed: 28424376
DOI: 10.1042/CS20160669 -
JCI Insight Oct 2022Antithrombin, a major endogenous anticoagulant, is a serine protease inhibitor (serpin). We characterized the biological and clinical impact of variants involving...
Antithrombin, a major endogenous anticoagulant, is a serine protease inhibitor (serpin). We characterized the biological and clinical impact of variants involving C-terminal antithrombin. We performed comprehensive molecular, cellular, and clinical characterization of patients with C-terminal antithrombin variants from a cohort of 444 unrelated individuals with confirmed antithrombin deficiency. We identified 17 patients carrying 12 C-terminal variants, 5 of whom had the p.Arg445Serfs*17 deletion. Five missense variants caused qualitative deficiency, and 7, including 4 insertion-deletion variants, induced severe quantitative deficiency, particularly p.Arg445Serfs*17 (antithrombin <40%). This +1 frameshift variant had a molecular size similar to that of WT antithrombin but possessed a different C-terminus. Morphologic and cotransfection experiments showed that recombinant p.Arg445Serfs*17 was retained at the endoplasmic reticulum and had a dominant-negative effect on WT antithrombin. Characterization of different 1+ frameshift, aberrant C-terminal variants revealed that protein secretion was determined by frameshift site. The introduction of Pro441 in the aberrant C-terminus, shared by 5 efficiently secreted variants, partially rescued p.Arg445Serfs*17 secretion. C-terminal antithrombin mutants have notable heterogeneity, related to variant type and localization. Aberrant C-terminal variants caused by 1+ frameshift, with similar size as WT antithrombin, may be secreted or not, depending on frameshift site. The severe clinical phenotypes of these genetic changes are consistent with their dominant-negative effects.
Topics: Antithrombin III; Antithrombins; Endoplasmic Reticulum; Serine Proteinase Inhibitors; Serpins
PubMed: 36214221
DOI: 10.1172/jci.insight.161430 -
Blood Advances Feb 2022Plasmodium falciparum-derived histidine-rich protein II (HRPII) has been shown to inhibit heparin-dependent anticoagulant activity of antithrombin (AT) and induce...
Plasmodium falciparum-derived histidine-rich protein II (HRPII) has been shown to inhibit heparin-dependent anticoagulant activity of antithrombin (AT) and induce inflammation in vitro and in vivo. In a recent study, we showed that HRPII interacts with the AT-binding vascular glycosaminoglycans (GAGs) not only to disrupt the barrier-permeability function of endothelial cells but also to inhibit the antiinflammatory signaling function of AT. Here we investigated the mechanisms of the proinflammatory function of HRPII and the protective activity of AT in cellular and animal models. We found that AT competitively inhibits the GAG-dependent HRPII-mediated activation of NF-κB and expression of intercellular cell adhesion molecule 1 (ICAM1) in endothelial cells. Furthermore, AT inhibits HRPII-mediated histone H3 citrullination and neutrophil extracellular trap (NET) formation in HL60 cells and freshly isolated human neutrophils. In vivo, HRPII induced Mac1 expression on blood neutrophils, MPO release in plasma, neutrophil infiltration, and histone H3 citrullination in the lung tissues. HRPII also induced endothelial cell activation as measured by increased ICAM1 expression and elevated vascular permeability in the lungs. AT effectively inhibited HRPII-mediated neutrophil infiltration, NET formation, and endothelial cell activation in vivo. AT also inhibited HRPII-meditated deposition of platelets and fibrin(ogen) in the lungs and circulating level of von Willebrand factor in the plasma. We conclude that AT exerts protective effects against pathogenic effects of P falciparum-derived HRPII in both cellular and animal models.
Topics: Animals; Anticoagulants; Antigens, Protozoan; Antithrombin III; Antithrombins; Endothelial Cells; Histidine; Histones; Inflammation; Plasmodium falciparum; Protozoan Proteins
PubMed: 34768285
DOI: 10.1182/bloodadvances.2021005836 -
Haematologica Oct 2023
Topics: Humans; Antithrombins; Founder Effect; Poland; Antithrombin III; Mutation; Anticoagulants
PubMed: 37021543
DOI: 10.3324/haematol.2022.282459