Abstract
Tissue factor (TF) is expressed in vascular and nonvascular tissues and functions in several pathways, including embryonic development, inflammation, and cell migration. Many risk factors for atherosclerosis, including hypertension, diabetes, obesity, and smoking, increase TF expression. To better understand the TF-related mechanisms in atherosclerosis, here we investigated the role of 12/15-lipoxygenase (12/15-LOX) in TF expression. 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE), the major product of human 15-LOXs 1 and 2, induced TF expression and activity in a time-dependent manner in the human monocytic cell line THP1. Moreover, TF suppression with neutralizing antibodies blocked 15(S)-HETE-induced monocyte migration. We also found that NADPH- and xanthine oxidase-dependent reactive oxygen species (ROS) production, calcium/calmodulin-dependent protein kinase IV (CaMKIV) activation, and interactions between nuclear factor of activated T cells 3 (NFATc3) and FosB proto-oncogene, AP-1 transcription factor subunit (FosB) are involved in 15(S)-HETE-induced TF expression. Interestingly, NFATc3 first induced the expression of its interaction partner FosB before forming the heterodimeric NFATc3-FosB transcription factor complex, which bound the proximal AP-1 site in the TF gene promoter and activated TF expression. We also observed that macrophages from 12/15-LOX-/- mice exhibit diminished migratory response to monocyte chemotactic protein 1 (MCP-1) and lipopolysaccharide compared with WT mouse macrophages. Similarly, compared with WT macrophages, monocytes from 12/15-LOX-/- mice displayed diminished trafficking, which was rescued by prior treatment with 12(S)-HETE, in a peritonitis model. These observations indicate that 15(S)-HETE-induced monocyte/macrophage migration and trafficking require ROS-mediated CaMKIV activation leading to formation of NFATc3 and FosB heterodimer, which binds and activates the TF promoter.
Highlights
Tissue factor (TF) is expressed in vascular and nonvascular tissues and functions in several pathways, including embryonic development, inflammation, and cell migration
We found that NADPH- and xanthine oxidase– dependent reactive oxygen species (ROS) production, calcium/ calmodulin-dependent protein kinase IV (CaMKIV) activation, and interactions between nuclear factor of activated T cells 3 (NFATc3) and FosB proto-oncogene, AP-1 transcription factor subunit (FosB) are involved in 15(S)-HETE–induced TF expression
Because many studies including our own have shown a role for 12/15-LOX in atherogenesis [21, 23, 26], we asked the question whether there is any link between 12/15LOX and TF in the pathogenesis of atherosclerosis, monocyte/macrophage buildup in the vessel wall
Summary
Tissue factor (TF) is expressed in vascular and nonvascular tissues and functions in several pathways, including embryonic development, inflammation, and cell migration. 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE), the major product of human 15-LOXs 1 and 2, induced TF expression and activity in a time-dependent manner in the human monocytic cell line THP1. Compared with WT macrophages, monocytes from 12/15-LOX؊/؊ mice displayed diminished trafficking, which was rescued by prior treatment with 12(S)-HETE, in a peritonitis model These observations indicate that 15(S)-HETE–induced monocyte/macrophage migration and trafficking require ROS-mediated CaMKIV activation leading to formation of NFATc3 and FosB heterodimer, which binds and activates the TF promoter. B, quiescent THP1 cells were treated with vehicle or the indicated HETE (0.1 M) for 2 h, and TF mRNA, protein, and activity were measured as described in A. The bar graphs represent mean Ϯ S.D. values of three experiments. *, p Ͻ 0.01 versus vehicle control or control ASO; **, p Ͻ 0.01 versus 15(S)-HETE, TF, or control ASO ϩ 15(S)-HETE
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