Factor Xa induces tissue factor expression in endothelial cells by P44/42 MAPK and NF-κB-dependent pathways

Anti-Inflammatory and Anticancer Effects of Anticoagulant Therapy in Patients with Malignancy

Optimizing the anticoagulation therapy is of pivotal importance in patients with a malignant tumor, as venous thromboembolism (VTE) has become the second-leading cause of death in this population. Cancer can highly increase the risk of thrombosis and bleeding. Consequently, the management of cancer-associated VTE is complex. In recent years, translational research has intensified, and several studies have highlighted the role of inflammatory cytokines in cancer growth and progression. Simultaneously, the pleiotropic effects of anticoagulants currently recommended for VTE have emerged. In this review, we describe the anti-inflammatory and anticancer effects of both direct oral anticoagulants (DOACs) and low-molecular-weight heparins (LWMHs).

The effectiveness of atorvastatin for the prevention of deep vein thrombosis in cancer patients undergoing chemotherapy : A randomised controlled trial: open label

BACKGROUND

Deep vein thrombosis (DVT) is a common complication in cancer. Although thromboprophylaxis in cancer patients is recommended by the guidelines, clinicians' use of thromboprophylaxis remains limited due to cost, bleeding complications, and reluctance to give injectable anticoagulants. Inflammation plays essential roles in the pathogenesis of cancer-associated thrombosis. Owing to its ability to decrease proinflammatory cytokines, statins have anti-inflammatory properties. Thus, statins can be possibly utilized as thromboprophylaxis therapy in cancer patients undergoing chemotherapy.

OBJECTIVE

To compare the effectiveness of atorvastatin and rivaroxaban for DVT prevention in high-risk thrombosis patients with cancer undergoing chemotherapy.

METHODS

Double-blind, randomized controlled trial involving cancer patients with high-risk of thrombosis undergoing chemotherapy. We randomly assigned patients without deep-vein thrombosis at screening to receive atorvastatin 20 mg or rivaroxaban 10 mg daily for up to 90 days. Doppler ultrasonography was performed 90 days following chemotherapy to diagnose DVT. Average cost-effectiveness analysis was performed to analyze the cost of atorvastatin compared to rivaroxaban.

RESULTS

Of the eighty six patients who underwent randomization, primary efficacy end point was observed in 1 of 42 patients (2.3%) in the atorvastatin group and in 1 of 44 (2.2%) in the rivaroxaban group (Odds Ratio [OR], 0.953; 95% confidence interval [CI], 0.240 to 3.971; p = 1.000). There was a significant difference in the incidence of major bleeding, 2 of 42 patients (4.8%) in the atorvastatin group and 12 of 44 (27.3%) in the rivaroxaban group (OR, 0.257; 95% CI, 0.07 to 0.94; p = 0.007). The average cost-effectiveness ratio of using atorvastatin was lower than that of rivaroxaban.

CONCLUSION

Atorvastatin did not differ significantly from rivaroxaban in reducing the incidence of DVT, lower bleeding risk, and cost-effectiveness for thromboprophylaxis in high-risk thrombosis patients with cancer undergoing chemotherapy. The presence of limited statistical power and wide confidence intervals in this study needs further study to strengthen the efficacy of atorvastatin as DVT prophylaxis in cancer patients.

TRIAL REGISTRATION

ISRCTN71891829, Registration Date: 17/12/2020.

The Intricate Role of Non-Coding RNAs in Sepsis-Associated Disseminated Intravascular Coagulation

Disseminated Intravascular Coagulation (DIC) is a type of tissue and organ dysregulation in sepsis, due mainly to the effect of the inflammation on the coagulation system. Unfortunately, the underlying molecular mechanisms that lead to this disorder are not fully understood. Moreover, current biomarkers for DIC, including biological and clinical parameters, generally provide a poor diagnosis and prognosis. In recent years, non-coding RNAs have been studied as promising and robust biomarkers for a variety of diseases. Thus, their potential in the diagnosis and prognosis of DIC should be further studied. Specifically, the relationship between the coagulation cascade and non-coding RNAs should be established. In this review, microRNAs, long non-coding RNAs, and circular RNAs are studied in relation to DIC. Specifically, the axis between these non-coding RNAs and the corresponding affected pathway has been identified, including inflammation, alteration of the coagulation cascade, and endothelial damage. The main affected pathway identified is PI3K/AKT/mTOR axis, where several ncRNAs participate in its regulation, including miR-122-5p which is sponged by circ_0005963, ciRS-122, and circPTN, and miR-19a-3p which is modulated by circ_0000096 and circ_0063425. Additionally, both miR-223 and miR-24 were found to affect the PI3K/AKT pathway and were regulated by lncGAS5 and lncKCNQ1OT1, respectively. Thus, this work provides a useful pipeline of inter-connected ncRNAs that future research on their impact on DIC can further explore.

Circulating miR-320a-3p and miR-483-5p level associated with pharmacokinetic-pharmacodynamic profiles of rivaroxaban

BACKGROUND

Novel biomarkers for personalizing anticoagulation remain undetermined. We aimed to investigate the association of plasma miRNAs with pharmacokinetic-pharmacodynamic (PK-PD) profiles of rivaroxaban.

METHODS

This is a multicenter, exploratory study of miRNAs in a Chinese population. Healthy volunteers and patients receiving rivaroxaban were enrolled in the study. The area under the plasma concentration-time curve from time 0-t h (AUC_0-t) and anti-Xa activity at 3 h (AXA_3h) were measured in healthy volunteers, and AXA_3h was measured in patients. MiRNAs were detected by miRNA microarray in 26 healthy volunteers with 20 mg rivaroxaban, and quantitative reverse transcription polymerase chain reaction was used to exclude undetectable ones. MiR-320a-3p and miR-483-5p were then quantified in 65 healthy volunteers and 71 patients. MiRNA levels at 3 h were compared between high and low AXA_3h or AUC_0-t subjects and in matched patients with or without bleeding during follow-up. The miRNA targets were predicted by TargetScan, miRTarBase, and miRDB. Validated genes were included in GO enrichment and KEGG analyses. The protein-protein interaction network was established by STRING and visualized by Cytoscape.

RESULTS

A total of 136 Chinese subjects completed the study. In healthy volunteers taking 15 mg rivaroxaban, the miR-320a level at 3 h was significantly positively correlated with AXA_3h and AUC_0-t (r = 0.359, p = 0.025; r = 0.370, p = 0.02, respectively). A positive correlation was also observed between miR-483 and AXA_3h or AUC_0-t (r = 0.372, p = 0.02; r = 0.523, p = 0.001, respectively). MiR-320a and miR-483 levels at 3 h in the higher AUC_0-t group were significantly higher than those at 0 h. MiR-483 levels at 3 h may distinguish healthy volunteers with high or low AXA_3h or AUC_0-t. In the 10 mg fed subgroup, higher 3 h mir-483 levels were also observed compared with the control group. No significant differences were found in the comparisons among patients. Bioinformatic analysis showed that these miRNAs may play a regulatory role by targeting ABCG2, ITGB3, PTEN, MAPK1/3, etc. CONCLUSIONS: MiR-320a and miR-483 levels were found to be associated with PK and PD profiles of rivaroxaban in healthy Chinese subjects. Further studies are required to verify these findings and explore the mechanisms.

Put out the fire: The pleiotropic anti-inflammatory action of non-vitamin K oral anticoagulants

Non-vitamin K antagonist oral anticoagulants (NOACs) should be the preferred anticoagulant strategy for preventing ischemic stroke in patients with atrial fibrillation (AF) at increased thromboembolic risk and for treating deep venous thromboembolism (DVT) in the general population. Beyond their inhibiting action on the activated factor X (FXa) or thrombin (FIIa), NOACs showed some pleiotropic anti-inflammatory effects. The present review aimed to describe the role of FXa and FIIa in the inflammation pathway and the potential anti-inflammatory effects of NOACs.

Alboserpin, the Main Salivary Anticoagulant from the Disease Vector Aedes albopictus, Displays Anti-FXa-PAR Signaling In Vitro and In Vivo

Blood-feeding arthropods secrete potent salivary molecules, which include platelet aggregation inhibitors, vasodilators, and anticoagulants. Among these molecules, Alboserpin, the major salivary anticoagulant from the mosquito vector Aedes albopictus, is a specific inhibitor of the human coagulation factor Xa (FXa). In this study, we investigated the anti-inflammatory properties of Alboserpin, in vitro and in vivo. In vitro, Alboserpin inhibited FXa-induced protease-activated receptor (PAR)-1, PAR-2, PAR-3, VCAM, ICAM, and NF-κB gene expression in primary dermal microvascular endothelial cells. Alboserpin also prevented FXa-stimulated ERK1/2 gene expression and subsequent inflammatory cytokine release (MCP-1, TNF-α, IL-6, IL-8, IL-1β, IL-18). In vivo, Alboserpin reduced paw edema induced by FXa and subsequent release of inflammatory cytokines (CCL2, MCP-1, IL-1α, IL-6, IL-1β). Alboserpin also reduced FXa-induced endothelial permeability in vitro and in vivo. These findings show that Alboserpin is a potent anti-inflammatory molecule, in vivo and in vitro, and may play a significant role in blood feeding.

Dental pulp stem cell-derived exosomes suppress M1 macrophage polarization through the ROS-MAPK-NFκB P65 signaling pathway after spinal cord injury

Stem cell-derived exosomes have recently been regarded as potential drugs for treating spinal cord injury (SCI) by reducing reactive oxygen species (ROS) and suppressing M1 macrophage polarization. However, the roles of ROS and exosomes in the process of M1 macrophage polarization are not known. Herein, we demonstrated that ROS can induce M1 macrophage polarization and have a concentration-dependent effect. ROS can induce M1 macrophage polarization through the MAPK-NFκB P65 signaling pathway. Dental pulp stem cell (DPSC)-derived exosomes can reduce macrophage M1 polarization through the ROS-MAPK-NFκB P65 signaling pathway in treating SCI. This study suggested that DPSC-derived exosomes might be a potential drug for treating SCI. Disruption of the cycle between ROS and M1 macrophage polarization might also be a potential effective treatment by reducing secondary damage.

A thrombin-PAR1/2 feedback loop amplifies thromboinflammatory endothelial responses to the viral RNA analogue poly(I:C)

Activation of blood coagulation and endothelial inflammation are hallmarks of respiratory infections with RNA viruses that contribute significantly to the morbidity and mortality of patients with severe disease. We investigated how signaling by coagulation proteases affects the quality and extent of the response to the TLR3-ligand poly(I:C) in human endothelial cells. Genome-wide RNA profiling documented additive and synergistic effects of thrombin and poly(I:C) on the expression level of many genes. The most significantly active genes exhibiting synergistic induction by costimulation with thrombin and poly(I:C) included the key mediators of 2 critical biological mechanisms known to promote endothelial thromboinflammatory functions: the initiation of blood coagulation by tissue factor and the control of leukocyte trafficking by the endothelial-leukocyte adhesion receptors E-selectin (gene symbol, SELE) and VCAM1, and the cytokines and chemokines CXCL8, IL-6, CXCL2, and CCL20. Mechanistic studies have indicated that synergistic costimulation with thrombin and poly(I:C) requires proteolytic activation of protease-activated receptor 1 (PAR1) by thrombin and transactivation of PAR2 by the PAR1-tethered ligand. Accordingly, a small-molecule PAR2 inhibitor suppressed poly(I:C)/thrombin-induced leukocyte-endothelial adhesion, cytokine production, and endothelial tissue factor expression. In summary, this study describes a positive feedback mechanism by which thrombin sustains and amplifies the prothrombotic and proinflammatory function of endothelial cells exposed to the viral RNA analogue, poly(I:C) via activation of PAR1/2.

miR-19a-3p downregulates tissue factor and functions as a potential therapeutic target for sepsis-induced disseminated intravascular coagulation

Sepsis-induced disseminated intravascular coagulation (DIC) is a common life-threatening terminal-stage disease with high mortality. This study aimed to identify effective miRNAs as therapeutic targets for DIC. Bioinformatics and luciferase reporter gene analyses were performed to predict miR-19a-3p and validate that it targets tissue factor (TF). Quantitative real-time PCR was used to detect the expression of miR-19a-3p and TF, and TF procoagulant activity was determined using the chromogenic substrate method. Western blotting was used to detect the protein levels of TF, AKT serine/threonine kinase (AKT), extracellular regulated protein kinases (ERK), nuclear factor kappa B (NF-κB) P65, NFKB inhibitor alpha (IκB-a) and their phosphorylated counterparts in cell experiments. Furthermore, a rat model was established to explore the potential of miR-19a-3p in DIC treatment. As a result, a human clinical study revealed that miR-19a-3p was downregulated and that TF was upregulated in neonates with sepsis-induced DIC compared with those in the control group. The luciferase reporter assay showed that TF was a direct target of miR-19a-3p. Cell experiments verified that the mRNA and protein levels of TF, and the p-AKT/AKT, p-Erk/Erk, p-P65/P65, p-IκB-a/IκB-a ratios, and TF procoagulant activity were significantly decreased in lipopolysaccharide (LPS) -induced human peripheral blood mononuclear cells (PBMCs) and human umbilical vein endothelial cells (HUVECs) inhibited by overexpression of miR-19a-3p, and that miR-19a-3p regulating TF was dependent on the NF-kB and AKT pathways. In vivo, miR-19a-3p injection into DIC rats suppressed the mRNA expression of TF; more importantly, significant improvements in coagulation function indicators and in histopathologies of lung and kidney were observed. In conclusion, miR-19a-3p may suppress DIC by targeting TF and might be a potential therapeutic target in treating sepsis-induced DIC.

Factor Xa and thrombin induce endothelial progenitor cell activation. The effect of direct oral anticoagulants

Factor Xa (FXa) and thrombin exert non-hemostatic cellular actions primarily mediated through protease-activated receptors (PARs). We investigated the effect of FXa and thrombin on human late-outgrowth endothelial cells (OECs), a type of endothelial progenitor cells (EPCs), and on human umbilical vein endothelial cells (HUVECs). The effect of direct oral anticoagulants (DOACs), rivaroxaban and dabigatran, was also studied. The membrane expression of intercellular adhesion molecule-1 (ICAM-1) and the secretion of monocyte chemoattractant protein-1 (MCP-1) were used as cell activation markers. FXa and thrombin increase the ICAM-1 expression and the MCP-1 secretion on both cells, being higher on OECs. Vorapaxar, a specific PAR-1 antagonist, completely inhibits FXa-induced activation of both cells and thrombin-induced HUVEC activation, but only partially thrombin-induced OEC activation. Furthermore, thrombin-receptor activating peptide; TRAP-6, only partially activates OECs. OECs do not membrane-express PAR-4, therefore it may not be involved on thrombin-induced OEC activation. Rivaroxaban and dabigatran inhibit OEC and HUVEC activation by FXa and thrombin, respectively. Rivaroxaban enhances thrombin-induced OEC and HUVEC activation, which is completely inhibited by vorapaxar. The inhibition of OEC and HUVEC activation by vorapaxar and DOACs may represent a new pleiotropic effect of these drugs. The pathophysiological and clinical significance of our findings need to be established.

Activated clotting factor X mediates mitochondrial alterations and inflammatory responses via protease-activated receptor signaling in alveolar epithelial cells

There is growing evidence for the contribution of the activated coagulation factor X (FXa) in the development of chronic inflammatory lung diseases. Therefore, we aimed to investigate effects of exogenous FXa on mitochondrial and metabolic function as well as the induction of inflammatory molecules in type II alveolar epithelial cells. Effects of FXa on epithelial cells were investigated in A549 cell line. Activation of extracellular signal-regulated kinase (ERK) and induction of inflammatory molecules were examined by immunoblot and gene expression analysis. Mitochondrial function was assessed by the measurement of oxygen consumption during maximal oxidative phosphorylation and quantitative determination of cardiolipin oxidation. Apoptosis was tested using a caspase 3 antibody. Metabolic activity and lactate dehydrogenase assay were applied for the detection of cellular viability. FXa activated ERK1/2 and induced an increase in the expression of pro-inflammatory cytokines, which was prevented by an inhibitor of FXa, edoxaban, or an inhibitor of protease-activated receptor 1, vorapaxar. Exposure to FXa caused mitochondrial alteration with restricted capacity for ATP generation, which was effectively prevented by edoxaban, vorapaxar and GB83 (inhibitor of protease-activated receptor 2). Of note, exposure to FXa did not initiate apoptosis in epithelial cells. FXa-dependent pro-inflammatory state and impairment of mitochondria did not reach the level of significance in lung epithelial cells. However, these effects might limit regenerative potency of lung epithelial cells, particular under clinical circumstances where lung injury causes exposure to clotting factors.

Nonhemostatic Activities of Factor Xa: Are There Pleiotropic Effects of Anti-FXa Direct Oral Anticoagulants?

Factor Xa (FXa) is the key serine protease of the coagulation cascade as it is the point of convergence of the intrinsic and extrinsic pathways, leading to the formation of thrombin. Factor Xa is an established target of anticoagulation therapy, due to its central role in coagulation. Over the past years, several direct oral anticoagulants (DOACs) targeting FXa have been developed. Rivaroxaban, apixaban, and edoxaban are used in clinical practice for prevention and treatment of thrombotic diseases. Increasing evidence suggests that FXa exerts nonhemostatic cellular effects that are mediated mainly through protease-activated receptors-1 and -2 and are involved in pathophysiological conditions, such as atherosclerosis, inflammation, and fibrosis. Direct inhibition of FXa by DOACs could be beneficial in these conditions. This is a narrative review that focuses on the cellular effects of FXa in various cell types and conditions, as well as on the possible pleiotropic effects of FXa-targeting DOACs.

Thrombin selectively induces transcription of genes in human monocytes involved in inflammation and wound healing

Thrombin is essential for blood coagulation but functions also as a mediator of cellular signalling. Gene expression microarray experiments in human monocytes revealed thrombin-induced upregulation of a limited subset of genes, which are almost exclusively involved in inflammation and wound healing. Among these, the expression of F3 gene encoding for tissue factor (TF) was enhanced indicating that this physiological initiator of coagulation cascade may create a feed-forward loop to enhance blood coagulation. Activation of protease-activated receptor type 1 (PAR1) was shown to play a main role in promoting TF expression. Moreover, thrombin induced phosphorylation of ERK1/2, an event that is required for expression of thrombin-regulated genes. Thrombin also increased the expression of TF at the protein level in monocytes as evidenced by Western blot and immunostaining. Furthermore, FXa generation induced by thrombin-stimulated monocytes was abolished by a TF blocking antibody and therefore it is entirely attributable to the expression of tissue factor. This cellular activity of thrombin provides a new molecular link between coagulation, inflammation and wound healing.

Factor Xa Mediates Calcium Flux in Endothelial Cells and is Potentiated by Igg From Patients With Lupus and/or Antiphospholipid Syndrome

Factor (F) Xa reactive IgG isolated from patients with antiphospholipid syndrome (APS) display higher avidity binding to FXa with greater coagulant effects compared to systemic lupus erythematosus (SLE) non APS IgG. FXa signalling via activation of protease-activated receptors (PAR) leads to increased intracellular calcium (Ca²⁺). Therefore, we measured alterations in Ca²⁺ levels in human umbilical vein endothelial cells (HUVEC) following FXa-mediated PAR activation and investigated whether FXa reactive IgG from patients with APS or SLE/APS- alter these responses. We observed concentration-dependent induction of Ca²⁺ release by FXa that was potentiated by APS-IgG and SLE/APS- IgG compared to healthy control subjects’ IgG, and FXa alone. APS-IgG and SLE/APS- IgG increased FXa mediated NFκB signalling and this effect was fully-retained in the affinity purified anti-FXa IgG sub-fraction. Antagonism of PAR-1 and PAR-2 reduced FXa-induced Ca²⁺ release. Treatment with a specific FXa inhibitor, hydroxychloroquine or fluvastatin significantly reduced FXa-induced and IgG-potentiated Ca²⁺ release. In conclusion, PAR-1 and PAR-2 are involved in FXa-mediated intracellular Ca²⁺ release in HUVEC and FXa reactive IgG from patients with APS and/or SLE potentiate this effect. Further work is required to explore the potential use of IgG FXa reactivity as a novel biomarker to stratify treatment with FXa inhibitors in these patients.

Metformin suppresses intrahepatic coagulation activation in mice with lipopolysaccharide/D‑galactosamine‑induced fulminant hepatitis

Metformin is a widely‑used antidiabetic drug with hypoglycemic activity and previously described anti‑inflammatory properties. Previous studies have demonstrated that metformin attenuates endotoxic hepatitis, however the mechanisms remain unclear. Inflammation and coagulation are closely associated pathological processes, therefore the potential effects of metformin on key steps in activation of the coagulation system were further investigated in endotoxic hepatitis induced by lipopolysaccharide/D‑galactosamine (LPS/D‑Gal). The current study demonstrated that treatment with metformin significantly suppressed the upregulation of tissue factor and plasminogen activator inhibitor‑1 in LPS/D‑Gal‑exposed mice. In addition, a reduction in the expression of interleukin 6 and inhibition of nuclear translocation of nuclear factor‑κB were observed. These data indicate that the LPS/D‑Gal‑induced elevation of the stable protein level of hypoxia inducible factor 1α, the mRNA level of erythropoietin, vascular endothelial growth factor and matrix metalloproteinase‑3, and the hepatic level of lactic acid were also suppressed by metformin. The current study indicates that the suppressive effects of metformin on inflammation‑induced coagulation may be an additional mechanism underlying the hepatoprotective effects of metformin in mice with LPS/D‑Gal‑induced fulminant hepatitis.

Thrombin down-regulates tissue factor pathway inhibitor expression in a PI3K/nuclear factor-κB-dependent manner in human pleural mesothelial cells

Tissue factor pathway inhibitor (TFPI) is the primary inhibitor of the extrinsic coagulation cascade, and its expression is reported to be relatively stable. Various pathophysiologic agents have been shown to influence TFPI activity by regulating its expression or by modifying the protein. It is not clear how TFPI activity is regulated in normal physiology or in injury. Because thrombin and TFPI are locally elaborated in pleural injury, we sought to determine if thrombin could regulate TFPI in human pleural mesothelial cells (HPMCs). Thrombin significantly decreased TFPI mRNA and protein levels by > 70%. Thrombin-mediated down-regulation of TFPI promoted factor X activation by HPMCs. The ability of thrombin to significantly decrease TFPI mRNA and protein levels was maintained at nanomolar concentrations. Protease-activated receptor (PAR)-1, a mediator of thrombin signaling, is detectable in the mesothelium in human and murine pleural injury. PAR-1 silencing blocked thrombin-mediated decrements of TFPI in HPMCs. Thrombin activates PI3K/Akt and nuclear factor κB (NF-κB) signaling in HPMCs. Inhibition of PI3K (by PX-866) and NF-κB (by SN50) prevented thrombin-mediated TFPI mRNA and protein down-regulation. These are the first studies to demonstrate that thrombin decreases TFPI expression in HPMCs. Our findings demonstrate a novel mechanism by which thrombin regulates TFPI expression in HPMCs and promotes an unrestricted procoagulant response, and suggest that interactions between PI3K and NF-κB signaling pathways are linked in HPMCs and control TFPI expression. These findings raise the possibility that targeting this pathway could limit the ability of the mesothelium to support extravascular fibrin deposition and organization associated with pleural injury.

MicroRNA-20b and ERK1/2 pathway independently regulate the expression of tissue factor in hematopoietic and trophoblastic differentiation of human embryonic stem cells

Introduction

Tissue factor (TF) is expressed in various types of cells. TF expression is essential for many biological processes, such as blood coagulation and embryonic development, while its high expression in stem cells often leads to failure of transplantation. In this study, we used the human embryonic stem cell (hESC) culture system to understand the molecular mechanisms by which TF expression is regulated in hESC-derived hematopoietic and trophoblastic cells.

Methods

hESCs were induced in vitro to differentiate into hematopoietic and trophoblastic cells. TF expression in various types of cells during these differentiation processes was examined by quantitative real-time polymerase chain reaction analysis and western blot analysis. The regulatory mechanisms of TF expression were investigated by miRNA expression analysis, luciferase report assay, TF mRNA and protein analysis, and pathway phosphorylation analysis.

Results

We first found that TF was expressed only in trophoblasts and granulocyte–monocyte (G-M) cells differentiated from hESCs; and then demonstrated that miR-20b downregulated and Erk1/2 signaling pathway upregulated the TF expression in trophoblasts and G-M cells. Finally, we found that miR-20b downregulated the TF expression independently of the Erk1/2 signaling pathway.

Conclusions

The miR-20b and Erk1/2 pathway independently regulate expression of TF in trophoblasts and G-M cells differentiated from hESCs. These findings will open an avenue to further illustrate the functions of TF in various biological processes.

Coagulation factor Xa induces an inflammatory signalling by activation of protease-activated receptors in human atrial tissue

Activated factor X (FXa) is an important player in the coagulation cascade responsible for thrombin generation, which is activated during atrial fibrillation. Increasing evidence suggests that FXa influences cell signalling in various cell types by activating protease-activated receptors (PARs). It is so far not known if molecular effects of FXa affect atrial signal transduction. To study the effects of FXa, human atrial tissue slices were cultivated with FXa up to 24h. Additionally, rapid pacing was applied at 4Hz to resemble atrial fibrillation. The inhibitory impact of FXa antagonist (Rivaroxaban), protease-activated receptor 1 antagonist (SCH79797), and protease-activated receptor 2 antagonist (GB83) were analysed under experimental conditions. The exposure of atrial tissue to FXa resulted in the 1.7 fold upregulation of PAR2-mRNA, activation of MAP kinases (ERK1/2) and NF-κB signalling. Furthermore FXa increased the expression of adhesion molecule ICAM-1 (1.82 ± 0.20), chemokine IL-8 (1.94 ± 0.20), as well as prothrombotic molecule PAI-1 (1.52 ± 0.17). The combination of rapid pacing and FXa caused significant upregulation of PAR1 (2.82 ± 0.22), PAR2 (2.66 ± 0.40), ICAM-1 (2.13 ± 0.25), IL-8 (2.22 ± 0.24), LOX-1 (2.59 ± 0.35), and PAI-1 (2.65 ± 0.52) at the mRNA level. Rivaroxaban and GB83 prevented upregulation of PARs, ICAM-1, LOX-1, IL-8, and activation of MAP kinases. The elevation in the expression of PAI-1 was hindered in the presence of SCH79797, or Rivaroxaban. The present study indicates that FXa mediates inflammatory signalling in atrial tissue. Importantly, FXa and tachyarrhythmia act synergistically to increase expression of protease-activated receptors and inflammatory mediators. Rivaroxaban prevented effectively FXa-induced molecular effects in human atrial tissue particularly during rapid pacing.

Overexpression of high mobility group protein B1 correlates with the proliferation and metastasis of lung adenocarcinoma cells

High mobility group protein B1 (HMGB1) plays an important role in a number of clinical conditions, such as autoimmunity, cardiovascular disease and cancer. Evidence suggests that HMGB1 is critical in the development and progression of numerous types of tumor. However, the underlying molecular mechanisms for the HMGB1-mediated progression and metastasis of lung cancer have not yet been elucidated. In this study, we investigated the role of HMGB1 in lung adenocarcinoma and the mechanisms by which it contributes to carcinogenesis and metastasis. We demonstrated that there was an increase in the expression of HMGB1 in primary cancer tissues compared to the matched adjacent non-cancerous tissues. The expression levels of TOB1 in the normal human bronchial epithelial (HBE) cell line and 10 lung cancer cell lines were determined by reverse transcription-PCR (RT-PCR). The results revealed that HMGB1 expression increased in 8 cell lines compared with the HBE cell line. The A549 and NCI-H1975 cells were transfected with HMGB1 recombinant plasmid. We discovered that the overexpression of HMGB1 promoted cell growth and metastasis in the 2 cell lines. Further investigation revealed that exogenously expressed HMGB1 enhanced the activation of p38 and Erk1/2, in addition to the expression of nuclear factor (NF)-κB. We propose that HMGB1 functions as a tumor promoter and that it regulates the proliferation and invasion of lung cancer cells by modulating the activation of the Erk1/2 and p38 mitogen-activated protein kinase (MAPK) signaling pathways.

Tissue factor, blood coagulation, and beyond: an overview

Emerging evidence shows a broad spectrum of biological functions of tissue factor (TF). TF classical role in initiating the extrinsic blood coagulation and its direct thrombotic action in close relation to cardiovascular risks have long been established. TF overexpression/hypercoagulability often observed in many clinical conditions certainly expands its role in proinflammation, diabetes, obesity, cardiovascular diseases, angiogenesis, tumor metastasis, wound repairs, embryonic development, cell adhesion/migration, innate immunity, infection, pregnancy loss, and many others. This paper broadly covers seminal observations to discuss TF pathogenic roles in relation to diverse disease development or manifestation. Biochemically, extracellular TF signaling interfaced through protease-activated receptors (PARs) elicits cellular activation and inflammatory responses. TF diverse biological roles are associated with either coagulation-dependent or noncoagulation-mediated actions. Apparently, TF hypercoagulability refuels a coagulation-inflammation-thrombosis circuit in “autocrine” or “paracrine” fashions, which triggers a wide spectrum of pathophysiology. Accordingly, TF suppression, anticoagulation, PAR blockade, or general anti-inflammation offers an array of therapeutical benefits for easing diverse pathological conditions.