BMP-7 induces TF expression in human monocytes by increasing F3 transcriptional activity.

Background: Bone morphogenetic protein (BMP)-7, a major regulator of bone metabolism, inhibits ectopic calcification in atherosclerotic plaques. We have recently reported that BMP-7 is also a potent inducer of tissue factor (TF) in human mononuclear cells (MNCs). While nuclear factor kappa beta (NF-kB) and activation protein-1 (AP-1) are the transcription factors essential for inducible expression of human TF gene (F3), the mechanisms responsible for TF induction by BMP-7 are not known.

Evidence for direct transfer of tissue factor from monocytes to platelets in whole blood.

Varying specificity of anti-tissue factor (anti-TF) antibodies gives rise to erroneous conclusions on TF positivity of platelets. Although monocytes are a well established source of TF in whole blood, there is no consensus whether platelets express or acquire TF from external sources. To test whether platelets can acquire TF expressed in monocytes, we studied a transfer of TF-yellow fluorescent protein (TF-YFP) from monocytes nucleofected with TF-YFP to platelets in a whole blood model.

Circulating monocytes mirror the imbalance in TF and TFPI expression in carotid atherosclerotic plaques with lipid-rich and calcified morphology.

Background: Thrombogenicity of atherosclerotic plaque largely depends on plaque morphology and their content of tissue factor (TF) and tissue factor pathway inhibitor (TFPI). The relationship between morphological composition of plaque (lipid-rich or calcified) and expression of TF and TFPI in circulating blood monocytes and within the plaques is not characterized.

Objective: To investigate whether lipid-rich (echolucent) or calcified (echogenic) morphology of carotid atherosclerotic plaques is associated with differences in TF and TFPI expression in circulating blood monocytes and within carotid atherosclerotic plaques.

BMP-2 inhibits TF expression in human monocytes by shutting down MAPK signaling and AP-1 transcriptional activity.

Background: We have recently identified bone morphogenetic protein (BMP)-2 as a novel inhibitor of tissue factor (TF) expression in lipopolysaccharide (LPS)-activated human monocytes, and now sought for intracellular mechanisms.

Methods: Here, we studied activation status of mitogen activated protein kinases (MAPKs) extracellular signal-regulated protein kinase (Erk) 1/2, p38, and c-Jun N-terminal kinase (JNK) as well as transcription factors activator protein (AP)-1 and nuclear factor kappa B (NF-kB), which regulate inducible expression of TF.

Results: Human mononuclear cells (MNCs) responded to BMP-2 stimulation with activation of canonic Smad1/5/8 signaling.

Low thrombogenicity of calcified atherosclerotic plaques is associated with bone morphogenetic protein-2-dependent inhibition of tissue factor expression.

Morphology of atherosclerotic plaque is a major determinant of plaque thrombogenicity. Calcified atherosclerotic lesions are less prone to thrombosis and contain less tissue factor (TF) than lipid-rich plaques. Although bone morphogenetic protein (BMP)-2 is a known mediator of vascular calcification, the role of BMP-2 in the regulation of plaque thrombogenicity has not been established.