Expression and localization of tissue factor pathway inhibitor-2 in normal and atherosclerotic human vessels.
Tissue factor pathway inhibitor-2 (TFPI-2) is a Kunitz-type, serine protease inhibitor with inhibitory activity toward activated factor XI, plasma kallikrein, plasmin, certain matrix metalloproteinases, and the tissue factor:activated factor VII complex. In this study, we investigated TFPI-2 expression and localization in normal and atherosclerotic human arteries by using in situ hybridization and immunohistochemical techniques. In healthy human blood vessels, TFPI-2 was detected in the vascular endothelium alone. In human atherosclerotic tissues, TFPI-2 expression was assigned to macrophages, T cells, endothelial cells, and smooth muscle cells. Western blot analysis for TFPI-2 confirmed its production by cultured human aortic smooth muscle cells, U937 cells (monocytes), and Jurkat (T cell) cell lines. Reverse transcription-polymerase chain reaction revealed similar TFPI-2 expression levels in both monocytes and macrophages in culture. Electron microscopic study with immunogold labeling revealed the association of TFPI-2 antigen with both the extracellular matrix and plasma membranes. TFPI-2 antigen was detected in some areas of atheroma that also stained positively for both tissue factor and factor VII. Moreover, detection of TFPI-2 in close spatial proximity to plasmin/plasminogen on macrophages, on endothelial cells, and in matrix-rich areas highlighted its possible functional significance in the regulation of plasmin activity and downstream proteolytic mechanisms that occur in the atherosclerotic lesion.
Crawley
James T B
JT
Thrombosis Research Institute, London, England.
Goulding
David A
DA
Ferreira
Valérie
V
Severs
Nicholas J
NJ
Lupu
Florea
F
D015153:Blotting, Western; D003324:Coronary Artery Disease / Q000378:metabolism* / Q000473:pathology; D003331:Coronary Vessels / Q000737:chemistry* / Q000648:ultrastructure*; D015942:Factor VIIa / Q000037:antagonists & inhibitors*; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D007124:Immunoenzyme Techniques; D008264:Macrophages / Q000737:chemistry; D008854:Microscopy, Electron; D009131:Muscle, Smooth, Vascular / Q000737:chemistry / Q000648:ultrastructure; D010958:Plasminogen / Q000032:analysis; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
D006023:Glycoproteins; C021240:tissue-factor-pathway inhibitor 2; D010958:Plasminogen; D015942:Factor VIIa