The molecular landscape of sepsis severity in infants: enhanced coagulation, innate immunity, and T cell repression.

Introduction: Sepsis remains a major cause of mortality and morbidity in infants. In recent years, several gene marker strategies for the early identification of sepsis have been proposed but only a few have been independently validated for adult cohorts and applicability to infant sepsis remains unclear. Biomarkers to assess disease severity and risks of shock also represent an important unmet need. Methods: To elucidate characteristics driving sepsis in infants, we assembled a multi-transcriptomic dataset from public microarray datasets originating from five independent studies pertaining to bacterial sepsis in infant < 6-months of age (total n=335). We utilized a COmbat co-normalization strategy to enable comparative evaluation across multiple studies while preserving the relationship between cases and controls. Results: We found good concordance with only two out of seven of the published adult sepsis gene signatures (accuracy > 80%), highlighting the narrow utility of adult-derived signatures for infant diagnosis. Pseudotime analysis of individual subjects' gene expression profiles showed a continuum of molecular changes forming tight clusters concurrent with disease progression between healthy controls and septic shock cases. In depth gene expression analyses between bacteremia, septic shock, and healthy controls characterized lymphocyte activity, hemostatic processes, and heightened innate immunity during the molecular transition toward a state of shock. Discussion: Our analysis revealed the presence of multiple significant transcriptomic perturbations that occur during the progression to septic shock in infants that are characterized by late-stage induction of clotting factors, in parallel with a heightened innate immune response and a suppression of adaptive cell functionality.

Validation for the function of protein C in mouse models.

Objectives: Protein C (PC) is an anticoagulant that is encoded by the PROC gene. Validation for the function of PC was carried out in mouse models. Methods: In this study, autosomal recessive PC deficiency (PCD) was selected as the target, and the specific mutation site was chromosome 2 2q13-q14, PROC c.1198G>A (p.Gly400Ser) which targets G399S (GGT to AGC) in mouse models. To investigate the role of hereditary PC in mice models, we used CRISPR/Cas9 gene editing technology to create a mouse model with a genetic PCD mutation. Results: The two F0 generation positive mice produced using the CRISPR/Cas9 gene editing technique were chimeras, and the mice in F1 and F2 generations were heterozygous. There was no phenotype of spontaneous bleeding or thrombosis in the heterozygous mice, but some of them were blind. Blood routine results showed no significant difference between the heterozygous mice and wild-type mice (P > 0.05). Prothrombin time (PT), activated partial thromboplastin time (APTT), and thrombin time (TT) were prolonged in the heterozygous mice, while the level of fibrinogen content (FIB) decreased, suggesting secondary consumptive coagulation disease. The protein C activity of heterozygous mice was significantly lower than that of wild-type mice (P < 0.001), but there was no significant difference in protein C antigen levels (P > 0.05). H&E staining showed steatosis and hydrodegeneration in the liver of heterozygous mice. Necrosis and exfoliated epithelial cells could be observed in renal tubule lumen, forming cell or granular tubules. Hemosiderin deposition was found in the spleen along with splenic hemorrhage. Immunohistochemistry demonstrated significant fibrin deposition in the liver, spleen, and kidney of heterozygous mice. Conclusion: In this study, heterozygotes of the mouse model with a PC mutation were obtained. The function of PC was then validated in a mouse model through genotype, phenotype, and PC function analysis.

Machine learning identifies novel coagulation genes as diagnostic and immunological biomarkers in ischemic stroke.

BACKGROUND: Coagulation system is currently known associated with the development of ischemic stroke (IS). Thus, the current study is designed to identify diagnostic value of coagulation genes (CGs) in IS and to explore their role in the immune microenvironment of IS. METHODS: Aberrant expressed CGs in IS were input into unsupervised consensus clustering to classify IS subtypes. Meanwhile, key CGs involved in IS were further selected by weighted gene co-expression network analysis (WGCNA) and machine learning methods, including random forest (RF), support vector machine (SVM), generalized linear model (GLM) and extreme-gradient boosting (XGB). The diagnostic performance of key CGs were evaluated by receiver operating characteristic (ROC) curves. At last, quantitative PCR (qPCR) was performed to validate the expressions of key CGs in IS. RESULTS: IS patients were classified into two subtypes with different immune microenvironments by aberrant expressed CGs. Further WGCNA, machine learning methods and ROC curves identified ACTN1, F5, TLN1, JMJD1C and WAS as potential diagnostic biomarkers of IS. In addition, their expressions were significantly correlated with macrophages, neutrophils and/or T cells. GSEA also revealed that those biomarkers may regulate IS via immune and inflammation. Moreover, qPCR verified the expressions of ACTN1, F5 and JMJD1C in IS. CONCLUSIONS: The current study identified ACTN1, F5 and JMJD1C as novel coagulation-related biomarkers associated with IS immune microenvironment, which enriches our knowledge of coagulation-mediated pathogenesis of IS and sheds light on next-step in vivo and in vitro experiments to elucidate the relevant molecular mechanisms.

Establishment and verification of a prognostic model based on coagulation and fibrinolysis-related genes in hepatocellular carcinoma.

BACKGROUND: Studies have shown that coagulation and fibrinolysis (CFR) are correlated with Hepatocellular carcinoma (HCC) progression and prognosis. We aim to build a model based on CFR-correlated genes for risk assessment and prediction of HCC patient. METHODS: HCC samples were selected from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases respectively. The Molecular Signatures Database (MSigDB) was used to select the CFR genes. RiskScore model were established by single sample gene set enrichment analysis (ssGSEA), weighted correlation network analysis (WGCNA), multivariate Cox regression analysis, LASSO regression analysis. RESULTS: PCDH17, PGF, PDE2A, FAM110D, FSCN1, FBLN5 were selected as the key genes and designed a RiskScore model. Those key genes were Differential expressions in HCC cell and patients. Overexpression PDE2A inhibited HCC cell migration and invasion. The higher the RiskScore, the lower the probability of survival. The model has high AUC values in the first, third and fifth year prediction curves, indicating that the model has strong prediction performance. The difference analysis of clinicopathological features found that a great proportion of high clinicopathological grade samples showed higher RiskScore. RiskScore were positively correlated with immune scores and TIDE scores. High levels of immune checkpoints and immunomodulators were observed in high RiskScore group. High RiskScore groups may benefit greatly from taking traditional chemotherapy drugs. CONCLUSIONS: We screened CFR related genes to design a RiskScore model, which could accurately evaluate the prognosis and survival status of HCC patients, providing certain value for optimizing the clinical treatment of cancer in the future.

Exploring the role of coagulation-related genes in renal cell carcinoma: Implications for tumor microenvironment and prognostic biomarkers.

PURPOSE: Clear cell renal cell carcinoma (ccRCC) frequently progresses to advanced stages due to tumor thrombus (TTs) formation. In this study, we aimed to investigate the role of coagulation-related pathway activation in the progression of ccRCC. METHODS: Consensus clustering was used to identify coagulation-related molecular clusters of ccRCC patients from The Cancer Genome Atlas Program (TCGA) database. The function of coagulation and its correlation with the immune microenvironment were investigated. Protein-protein interactions and differential expression analysis were used to identify the key gene, which was verified by external experiments. The coagulation-associated risk score was constructed by cox proportional hazards regression. RESULTS: Notable disparities were detected in immune characteristics, prognostic differentiation and drug sensitivity between two coagulation-related clusters. Through the integration of clinical stage significance and protein-protein interactions, the key gene MMP9 was screened and it was significantly correlated with CD4+T cells, CD8+T cells and Treg cells. A coagulation-related risk score prognostic model was developed in the Cancer Genome Atlas (TCGA) cohort for risk stratification and prognosis prediction. The prognostic predictive values of the coagulation-related risk score were further authenticated in both TCGA-KIRC and E-MTAB-1980 cohorts. CONCLUSION: There is an obvious correlation between the coagulation and the tumor microenvironment in ccRCC. As a key coagulation-related gene, MMP9 may promote the progression of renal cell carcinoma by influencing immune infiltration of CD8+T cells and Treg cells. Additionally, the risk score could be used as a durable prognostic biomarker, which could assist in clinical decision making for ccRCC patients.

C3AR1 is a regulatory factor associated with coagulation cascade and inflammation in sepsis.

Sepsis is a leading cause of mortality in intensive care units. Sepsis is associated with activation of the coagulation cascade and inflammation. The aim of this study was to identify coagulation-related genes in sepsis that may provide translational potential therapeutic targets. The datasets GSE28750, GSE95233, and GSE65682 were downloaded from the gene expression omnibus database. Consensus-weighted gene co-expression network analysis (WGCNA) was used to identify sepsis modules. Gene set enrichment analysis was used to identify genes enriched in the coagulation cascade. The value of hub-gene in immunological analysis was tested in the validation sets (GSE95233). The value of hub-gene in clinical prognosis was tested in the validation sets (GSE65582). One thousand one hundred seventy-six genes with high connectivity in the clinically significant module were identified as hub genes. Ten genes were found to be enriched in coagulation-related signaling pathways. C3AR1 was selected for further analysis. The immune infiltration analysis showed that lower expression of C3AR1 was associated with immune response in sepsis and could be an independent predictor of survival status in sepsis patients. Meanwhile, univariate and multivariate Cox analysis showed that C3AR1 had a significant correlation with survival. C3AR1 may become an effective biomarker for worse outcomes in sepsis patients associated with immune and coagulation cascade.

Clinical Implications of Discrepancy between One-Stage Clotting and Chromogenic Factor IX Activity in Hemophilia B.

BACKGROUND: Discrepancy in factor IX activity (FIX:C) between one-stage assay (OSA) and chromogenic substrate assay (CSA) in patients with hemophilia B (PwHB) introduces challenges for clinical management. AIM: To study the differences in FIX:C using OSA and CSA in moderate and mild hemophilia B (HB), their impact on classification of severity, and correlation with genotype. METHODS: Single-center study including 21 genotyped and clinically characterized PwHB. FIX:C by OSA was measured using ActinFSL (Siemens) and CSA by Biophen (Hyphen). In addition, in vitro experiments with wild-type FIX were performed. Reproducibility of CSA was assessed between three European coagulation laboratories. RESULTS: FIX:C by CSA was consistently lower than by OSA, with 10/17 PwHB having a more severe hemophilia type by CSA. OSA displayed a more accurate description of the clinical bleeding severity, compared with CSA. A twofold difference between OSA:CSA FIX:C was present in 12/17 PwHB; all patients had genetic missense variants in the FIX serine protease domain. Discrepancy was also observed with diluted normal plasma, most significant for values below 0.10 IU/mL. Assessment of samples with low FIX:C showed excellent reproducibility of the CSA results between the laboratories. CONCLUSION: FIX:C was consistently higher by OSA compared with the CSA. Assessing FIX:C by CSA alone would have led to diagnosis of a more severe hemophilia type in a significant proportion of patients. Our study suggests using both OSA and CSA FIX:C together with genotyping to classify HB severity and provide essential information for clinical management.

Biology of factor XI.

ABSTRACT: Unique among coagulation factors, the coagulation factor XI (FXI) arose through a duplication of the gene KLKB1, which encodes plasma prekallikrein. This evolutionary origin sets FXI apart structurally because it is a homodimer with 2 identical subunits composed of 4 apple and 1 catalytic domain. Each domain exhibits unique affinities for binding partners within the coagulation cascade, regulating the conversion of FXI to a serine protease as well as the selectivity of substrates cleaved by the active form of FXI. Beyond serving as the molecular nexus for the extrinsic and contact pathways to propagate thrombin generation by way of activating FIX, the function of FXI extends to contribute to barrier function, platelet activation, inflammation, and the immune response. Herein, we critically review the current understanding of the molecular biology of FXI, touching on some functional consequences at the cell, tissue, and organ level. We conclude each section by highlighting the DNA mutations within each domain that present as FXI deficiency. Together, a narrative review of the structure-function of the domains of FXI is imperative to understand the etiology of hemophilia C as well as to identify regions of FXI to safely inhibit the pathological function of activation or activity of FXI without compromising the physiologic role of FXI.

Developmental adcyap1b loss leads to hemorrhage, disrupted hemostasis, and a blood coagulation cascade in zebrafish.

BACKGROUND: Pituitary adenylate cyclase-activating polypeptide is a neuropeptide with diverse roles in biological processes. Its involvement in the blood coagulation cascade is unclear. OBJECTIVES: This study unraveled adcyap1b's role in blood coagulation using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 in zebrafish. Effects were validated via adcyap1b knockdown. Gene expression changes in adcyap1b mutants were explored, linking them to clotting disorders. An analysis of proca gene splicing illuminated its role in adcyap1b-related anticoagulation deficiencies. METHODS: Zebrafish were genetically modified using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 to induce adcyap1b knockout. Morpholino-mediated gene knockdown was employed for validation. Expression levels of coagulation factors, anticoagulant proteins, and fibrinolytic system genes were assessed in adcyap1b mutant zebrafish. Alternative splicing of proca gene was analyzed. RESULTS: Adcyap1b mutant zebrafish exhibited severe hemorrhage, clotting disorders, and disrupted blood coagulation. Morpholino-mediated knockdown replicated observed phenotypes. Downregulation in transcripts related to coagulation factors V and IX, anticoagulation protein C, and plasminogen was observed. Abnormal alternative splicing of the proca gene was identified, providing a mechanistic explanation for anticoagulation system deficiencies. CONCLUSION: Adcyap1b plays a crucial role in maintaining zebrafish blood coagulation and hemostasis. Its influence extends to the regulation of procoagulant and anticoagulant pathways, with abnormal alternative splicing contributing to observed deficiencies. These findings unveil a novel aspect of adcyap1b function, offering potential insights into similar processes in mammalian systems.

Yolk sac cell atlas reveals multiorgan functions during human early development.

The extraembryonic yolk sac (YS) ensures delivery of nutritional support and oxygen to the developing embryo but remains ill-defined in humans. We therefore assembled a comprehensive multiomic reference of the human YS from 3 to 8 postconception weeks by integrating single-cell protein and gene expression data. Beyond its recognized role as a site of hematopoiesis, we highlight roles in metabolism, coagulation, vascular development, and hematopoietic regulation. We reconstructed the emergence and decline of YS hematopoietic stem and progenitor cells from hemogenic endothelium and revealed a YS-specific accelerated route to macrophage production that seeds developing organs. The multiorgan functions of the YS are superseded as intraembryonic organs develop, effecting a multifaceted relay of vital functions as pregnancy proceeds.

Two to tango: endothelial cell TMEM16 scramblases drive coagulation and thrombosis.

Endothelial cells form a constitutively anticoagulant surface under homeostasis. While loss of this anticoagulant property is a hallmark of many cardiovascular diseases, the molecular mechanisms underlying the procoagulant transition remain incompletely understood. In this issue of the JCI, Schmaier et al. identify the phospholipid scramblases TMEM16E and TMEM16F, which support endothelial procoagulant activity through phosphatidylserine (PS) externalization. Genetic deletion of TMEM16E or TMEM16F or treatment with TMEM16 inhibitors prevented PS externalization and reduced fibrin formation in the vessel wall independently of platelets in a murine laser-injury model of thrombosis. These findings reveal a role for endothelial TMEM16E in thrombosis and identify TMEM16E as a potential therapeutic target for preventing thrombus formation.

The effects of coagulation factors on the risk of endometriosis: a Mendelian randomization study.

BACKGROUND: Endometriosis is recognized as a complex gynecological disorder that can cause severe pain and infertility, affecting 6-10% of all reproductive-aged women. Endometriosis is a condition in which endometrial tissue, which normally lines the inside of the uterus, deposits in other tissues. The etiology and pathogenesis of endometriosis remain ambiguous. Despite debates, it is generally agreed that endometriosis is a chronic inflammatory disease, and patients with endometriosis appear to be in a hypercoagulable state. The coagulation system plays important roles in hemostasis and inflammatory responses. Therefore, the purpose of this study is to use publicly available GWAS summary statistics to examine the causal relationship between coagulation factors and the risk of endometriosis. METHODS: To investigate the causal relationship between coagulation factors and the risk of endometriosis, a two-sample Mendelian randomization (MR) analytic framework was used. A series of quality control procedures were followed in order to select eligible instrumental variables that were strongly associated with the exposures (vWF, ADAMTS13, aPTT, FVIII, FXI, FVII, FX, ETP, PAI-1, protein C, and plasmin). Two independent cohorts of European ancestry with endometriosis GWAS summary statistics were used: UK Biobank (4354 cases and 217,500 controls) and FinnGen (8288 cases and 68,969 controls). We conducted MR analyses separately in the UK Biobank and FinnGen, followed by a meta-analysis. The Cochran's Q test, MR-Egger intercept test, and leave-one-out sensitivity analyses were used to assess the heterogeneities, horizontal pleiotropy, and stabilities of SNPs in endometriosis. RESULTS: Our two-sample MR analysis of 11 coagulation factors in the UK Biobank suggested a reliable causal effect of genetically predicted plasma ADAMTS13 level on decreased endometriosis risk. A negative causal effect of ADAMTS13 and a positive causal effect of vWF on endometriosis were observed in the FinnGen. In the meta-analysis, the causal associations remained significant with a strong effect size. The MR analyses also identified potential causal effects of ADAMTS13 and vWF on different sub-phenotypes of endometrioses. CONCLUSIONS: Our MR analysis based on GWAS data from large-scale population studies demonstrated the causal associations between ADAMTS13/vWF and the risk of endometriosis. These findings suggest that these coagulation factors are involved in the development of endometriosis and may represent potential therapeutic targets for the management of this complex disease.

Integrated analysis to identify the prognostic and immunotherapeutic roles of coagulation-associated gene signature in clear cell renal cell carcinoma.

The coagulation system is closely related to the physiological status and immune response of the body. Recent years, studies focusing on the association between coagulation system abnormalities and tumor progression have been widely reported. In clear cell renal cell carcinoma (ccRCC), poor prognosis often occurs in patients with venous tumor thrombosis and coagulation system abnormalities, and there is a lack of research in related fields. Significant differences in coagulation function were also demonstrated in our clinical sample of patients with high ccRCC stage or grade. Therefore, in this study, we analyzed the biological functions of coagulation-related genes (CRGs) in ccRCC patients using single-cell sequencing and TCGA data to establish the 5-CRGs based diagnostic signature and predictive signature for ccRCC. Univariate and multivariate Cox analyses suggested that prognostic signature could be an independent risk factor. Meanwhile, we applied CRGs for consistent clustering of ccRCC patients, and the two classes showed significant survival and genotype differences. The differences in individualized treatment between the two different subtypes were revealed by pathway enrichment analysis and immune cell infiltration analysis. In summary, we present the first systematic analysis of the significance of CRGs in the diagnosis, prognosis, and individualized treatment of ccRCC patients.

A thrombophilic allele of clotting Factor VII/VIIa promoting recurrent pulmonary emboli, clinical details, and a structural model of the altered protein: a case report.

BACKGROUND: The clotting or hemostasis system is a meticulously regulated set of enzymatic reactions that occur in the blood and culminate in formation of a fibrin clot. The precisely calibrated signaling system that prevents or initiates clotting originates with the activated Factor Seven (FVIIa) complexed with tissue factor (TF) formed in the endothelium. Here we describe a rare inherited mutation in the FVII gene which is associated with pathological clotting. CASE PRESENTATION: The 52-year-old patient, with European, Cherokee and African American origins, FS was identified as having low FVII (10%) prior to elective surgery for an umbilical hernia. He was given low doses of NovoSeven (therapeutic Factor VIIa) and had no unusual bleeding or clotting during the surgery. In fact, during his entire clinical course he had no unprovoked bleeding. Bleeding instances occurred with hemostatic stresses such as gastritis, kidney calculus, orthopedic surgery, or tooth extraction, and these were handled without factor replacement. On the other hand, FS sustained two unprovoked and life-threatening instances of pulmonary emboli, although he was not treated with NovoSeven at any time close to the events. Since 2020, he has been placed on a DOAC (Direct Oral Anticoagulant, producing Factor Xa inhibition) and has sustained no further clots. POSSIBLE MECHANISM OF (UNAUTHORIZED) FVII ACTIVATION: FS has a congenitally mutated FVII/FVIIa gene, which carries a R315W missense mutation in one allele and a mutated start codon (ATG to ACG) in the other allele, thus rendering the patient effectively homozygous for the missense FVII. Structure based comparisons with known crystal structures of TF-VIIa indicate that the patient's missense mutation is predicted to induce a conformational shift of the C170's loop due to crowding of the bulky tryptophan to a distorted "out" position (Fig. 1). This mobile loop likely forms new interactions with activation loop 3, stabilizing a more active conformation of the FVII and FVIIa protein. The mutant form of FVIIa may be better able to interact with TF, displaying a modified serine protease active site with enhanced activity for downstream substrates such as Factor X. CONCLUSIONS: Factor VII can be considered the gatekeeper of the coagulation system. Here we describe an inherited mutation in which the gatekeeper function is altered. Instead of the expected bleeding manifestations resulting from a clotting factor deficiency, the patient FS suffered clotting episodes. The efficacy of the DOAC in treating and preventing clots in this unusual situation is due to its target site of inhibition (anti-Xa), which lies downstream of the site of action of FVIIa/TF.

Post-transcriptional control of haemostatic genes: mechanisms and emerging therapeutic concepts in thrombo-inflammatory disorders.

The haemostatic system is pivotal to maintaining vascular integrity. Multiple components involved in blood coagulation have central functions in inflammation and immunity. A derailed haemostasis is common in prevalent pathologies such as sepsis, cardiovascular disorders, and lately, COVID-19. Physiological mechanisms limit the deleterious consequences of a hyperactivated haemostatic system through adaptive changes in gene expression. While this is mainly regulated at the level of transcription, co- and posttranscriptional mechanisms are increasingly perceived as central hubs governing multiple facets of the haemostatic system. This layer of regulation modulates the biogenesis of haemostatic components, for example in situations of increased turnover and demand. However, they can also be 'hijacked' in disease processes, thereby perpetuating and even causally entertaining associated pathologies. This review summarizes examples and emerging concepts that illustrate the importance of posttranscriptional mechanisms in haemostatic control and crosstalk with the immune system. It also discusses how such regulatory principles can be used to usher in new therapeutic concepts to combat global medical threats such as sepsis or cardiovascular disorders.

Domain Evolution of Vertebrate Blood Coagulation Cascade Proteins.

Vertebrate blood coagulation is controlled by a cascade containing more than 20 proteins. The cascade proteins are found in the blood in their zymogen forms and when the cascade is triggered by tissue damage, zymogens are activated and in turn activate their downstream proteins by serine protease activity. In this study, we examined proteomes of 21 chordates, of which 18 are vertebrates, to reveal the modular evolution of the blood coagulation cascade. Additionally, two Arthropoda species were used to compare domain arrangements of the proteins belonging to the hemolymph clotting and the blood coagulation cascades. Within the vertebrate coagulation protein set, almost half of the studied proteins are shared with jawless vertebrates. Domain similarity analyses revealed that there are multiple possible evolutionary trajectories for each coagulation protein. During the evolution of higher vertebrate clades, gene and genome duplications led to the formation of other coagulation cascade proteins.

Evolutionarily conserved role of hps1 in melanin production and blood coagulation in medaka fish.

Hermansky-Pudlak syndrome is an autosomal recessive disease characterized by albinism, visual impairment, and blood platelet dysfunction. One of the genes responsible for Hermansky-Pudlak syndrome, hps1, regulates organelle biogenesis and thus plays important roles in melanin production, blood clotting, and the other organelle-related functions in humans and mice. However, the function of hps1 in other species remains poorly understood. In this study, we discovered albino medaka fish during the maintenance of a wild-derived population and identified hps1 as the responsible gene using positional cloning. In addition to the specific absence of melanophore pigmentation, the hps1 mutant showed reduced blood coagulation, suggesting that hps1 is involved in clotting caused by both mammalian platelets and fish thrombocytes. Together, the findings of our study demonstrate that hps1 has an evolutionarily conserved role in melanin production and blood coagulation. In addition, our study presents a useful vertebrate model for understanding the molecular mechanisms of Hermansky-Pudlak syndrome.

Genetic Deletion of HLJ1 Does Not Affect Blood Coagulation in Mice.

HLJ1 (also called DNAJB4) is a member of the DNAJ/Hsp40 family and plays an important role in regulating protein folding and activity. However, there is little information about the role of HLJ1 in the regulation of physiological function. In this study, we investigated the role of HLJ1 in blood coagulation using wild-type C57BL/6 mice and HLJ1-null (HLJ1-/-) mice. Western blot analysis and immunohistochemistry were used to assess the expression and distribution of HLJ1 protein, respectively. The tail bleeding assay was applied to assess the bleeding time and blood loss. A coagulation test was used for measuring the activity of extrinsic, intrinsic and common coagulation pathways. Thromboelastography was used to measure the coagulation parameters in the progression of blood clot formation. The results showed that HLJ1 was detectable in plasma and bone marrow. The distribution of HLJ1 was co-localized with CD41, the marker of platelets and megakaryocytes. However, genetic deletion of HLJ1 did not alter blood loss and the activity of extrinsic and intrinsic coagulation pathways, as well as blood clot formation, compared to wild-type mice. Collectively, these findings suggest that, although HLJ1 appears in megakaryocytes and platelets, it may not play a role in the function of blood coagulation under normal physiological conditions.

Differences in thrombin and plasmin generation potential between East African and Western European adults: The role of genetic and non-genetic factors.

BACKGROUND: Geographic variability in coagulation across populations and their determinants are poorly understood. OBJECTIVE: To compare thrombin (TG) and plasmin (PG) generation parameters between healthy Tanzanian and Dutch individuals, and to study associations with inflammation and different genetic, host and environmental factors. METHODS: TG and PG parameters were measured in 313 Tanzanians of African descent living in Tanzania and 392 Dutch of European descent living in the Netherlands and related to results of a dietary questionnaire, circulating inflammatory markers, genotyping, and plasma metabolomics. RESULTS: Tanzanians exhibited an enhanced TG and PG capacity, compared to Dutch participants. A higher proportion of Tanzanians had a TG value in the upper quartile with a PG value in the lower/middle quartile, suggesting a relative pro-coagulant state. Tanzanians also displayed an increased normalized thrombomodulin sensitivity ratio, suggesting reduced sensitivity to protein C. In Tanzanians, PG parameters (lag time and TTP) were associated with seasonality and food-derived plasma metabolites. The Tanzanians had higher concentrations of pro-inflammatory cytokines, which correlated strongly with TG and PG parameters. There was limited overlap in genetic variation associated with TG and PG parameters between the two cohorts. Pathway analysis of genetic variants in the Tanzanian cohort revealed multiple immune pathways that were enriched with TG and PG traits, confirming the importance of co-regulation between coagulation and inflammation. CONCLUSIONS: Tanzanians have an enhanced TG and PG potential compared to Dutch individuals, which may relate to differences in inflammation, genetics and diet. These observations highlight the importance of better understanding of the geographic variability in coagulation across populations.