Tissue factor signalling modifies the expression and regulation of G1/S checkpoint regulators: Implications during injury and prolonged inflammation.

Tissue factor (TF) possesses additional physiological functions beyond initiating the coagulation cascade. Cellular signals initiated by cellular TF or on contact with TF‑containing microvesicles, contribute to wound healing through regulating a number of cellular properties and functions. TF regulates the cell cycle checkpoints, however the underlying signalling mechanisms have not been determined.

Comparison of assays measuring extracellular vesicle tissue factor in plasma samples: communication from the ISTH SSC Subcommittee on Vascular Biology.

Background: Scientific and clinical interest in extracellular vesicles (EVs) is growing. EVs that expose tissue factor (TF) bind factor VII/VIIa and can trigger coagulation. Highly procoagulant TF-exposing EVs are detectable in the circulation in various diseases, such as sepsis, COVID-19, or cancer.

Regulation of tissue factor activity by interaction with the first PDZ domain of MAGI1.

Background: Tissue factor (TF) activity is stringently regulated through processes termed encryption. Post-translational modification of TF and its interactions with various protein and lipid moieties allows for a multi-step de-encryption of TF and procoagulant activation. Membrane-associated guanylate kinase-with inverted configuration (MAGI) proteins are known to regulate the localisation and activity of a number of proteins including cell-surface receptors.

Synthesis and analysis of small molecules to restrain the function of tissue factor within tumour cells.

: The restriction of prolyl-protein cis/trans isomerase 1 (Pin1) activity has been shown to prevent the release of tissue factor (TF) leading to the accumulation of the latter protein within the cell. This study tested the ability of novel small molecules to inhibit Pin1, suppress TF activity and release, and induce cellular apoptosis. : Four compounds were designed and synthesised based on modification of 5-(-methoxyphenyl)-2-methylfuran-3-carbonyl amide and the outcome on MDA-MB-231 and primary cells examined.

De-Palmitoylation of Tissue Factor Regulates Its Activity, Phosphorylation and Cellular Functions.

In this study, the role of de-palmitoylation of tissue factor (TF) in the decryption of its activity was explored. TF-tGFP constructs were prepared by mutagenesis-substitution at Cys245 to prevent or mimic palmitolyation. Additionally, to reduce TF de-palmitoylation, the expression of palmitoyl-protein thioesterases (PPT) was suppressed.

Factor VIIa Regulates the Level of Cell-Surface Tissue Factor through Separate but Cooperative Mechanisms.

Procoagulant activity of tissue factor (TF) in response to injury or inflammation is accompanied with cellular signals which determine the fate of cells. However, to prevent excessive signalling, TF is rapidly dissipated through release into microvesicles, and/or endocytosis. To elucidate the mechanism by which TF signalling may become moderated on the surface of cells, the associations of TF, fVII/fVIIa, PAR2 and caveolin-1 on MDA-MB-231, BxPC-3 and 786-O cells were examined and compared to that in cells lacking either fVII/fVIIa or TF.

Accumulation of tissue factor in endothelial cells promotes cellular apoptosis through over-activation of Src1 and involves β1-integrin signalling.

Accumulation of tissue factor (TF) within cells leads to cellular apoptosis mediated through p38 and p53 pathways. In this study, the involvement of Src1 in the induction of TF-mediated cell apoptosis, and the mechanisms of Src1 activation were investigated. Human coronary artery endothelial cell (HCAEC) were transfected with plasmids to express the wild-type TF (TF-tGFP), or a mutant (Ser253 → Ala) which is incapable of being released from cells (TF-tGFP).

Apixaban Suppresses the Release of TF-Positive Microvesicles and Restrains Cancer Cell Proliferation through Directly Inhibiting TF-fVIIa Activity.

The activation of protease-activated receptor (PAR)-2 by factor Xa (fXa) promotes the release of tissue factor-positive microvesicles (TFMV), and contributes to proliferation in cancer cells. This study examined the ability of direct oral anticoagulants (DOACs), apixaban and rivaroxaban, to inhibit the release of TFMV from two cell lines (MDA-MB-231 and AsPC-1) as well as cell proliferation.Activation of the cells with fXa (10 nM) enhanced the release of TFMV but was suppressed in the presence of either DOAC.

The Ratio of Factor VIIa:Tissue Factor Content within Microvesicles Determines the Differential Influence on Endothelial Cells.

Tissue factor (TF)-positive microvesicles from various sources can promote cellular proliferation or alternatively induce apoptosis, but the determining factors are unknown. In this study the hypothesis that the ratio of fVIIa:TF within microvesicles determines this outcome was examined. Microvesicles were isolated from HepG2, BxPC-3, 786-O, MDA-MB-231, and MCF-7 cell lines and microvesicle-associated fVIIa and TF antigen and activity levels were measured.

Low molecular weight heparin and direct oral anticoagulants influence tumour formation, growth, invasion and vascularisation by separate mechanisms.

The bidirectional association between coagulation and cancer has been established. However, anticoagulant therapies have been reported to have beneficial outcomes by influencing the vascularisation of the tumours. In this study the influence of a set of anticoagulants on tumour formation, invasion and vascularisation was examined.

Alteration in endothelial permeability occurs in response to the activation of PAR2 by factor Xa but not directly by the TF-factor VIIa complex.

Alterations in the endothelial permeability occur in response to the activation of coagulation mechanisms in order to control clot formation. The activation of the protease activated receptors (PAR) can induce signals that regulate such cellular responses. PAR2 is a target for the coagulation factor Xa (fXa) and tissue factor-factor VIIa (TF-fVIIa) complex.

Peptidyl-prolyl isomerase 1 (Pin1) preserves the phosphorylation state of tissue factor and prolongs its release within microvesicles.

The exposure and release of TF is regulated by post-translational modifications of its cytoplasmic domain. Here, the potential of Pin1 to interact with the cytoplasmic domain of TF, and the outcome on TF function was examined. MDA-MB-231 and transfected-primary endothelial cells were incubated with either Pin1 deactivator Juglone, or its control Plumbagin, as well as transfected with Pin1-specific or control siRNA.

Oligoubiquitination of tissue factor on Lys255 promotes Ser253-dephosphorylation and terminates TF release.

Restriction of tissue factor (TF) activity at the cell surface and TF release are critical for prevention of excessive coagulation. This study examined the regulation of TF dephosphorylation and its release through ubiquitination. A plasmid containing the sequence to express the tandem protein TF-tGFP was mutated to include an arginine-substitution at Lys255 within TF.

Analysis of the potential of cancer cell lines to release tissue factor-containing microvesicles: correlation with tissue factor and PAR2 expression.

Background: Despite the association of cancer-derived circulating tissue factor (TF)-containing microvesicles and hypercoagulable state, correlations with the incidence of thrombosis remain unclear.

Methods: In this study the upregulation of TF release upon activation of various cancer cell lines, and the correlation with TF and PAR2 expression and/or activity was examined. Microvesicle release was induced by PAR2 activation in seventeen cell lines and released microvesicle density, microvesicle-associated TF activity, and phoshpatidylserine-mediated activity were measured.