Regulation of Tissue Factor by NF-kB Transcription Factor p50 Is Essential for the Pathogeneses of Deep Vein Thrombosis and Arterial Restenosis.

NF-kB transcription factors regulate the expression of tissue factor (TF), a principal initiator for the coagulation cascade. Dominant among the five cellular members of NF-kB transcription factors is the p50/p65 heterodimer. Here we report that Andrographolide (Andro; a 350-dalton antagonist that targets reduced cysteine⁶² of p50 for inhibition of NF-kB activation) and genetic deletion of p50 potently attenuated TF activity in stimulated endothelial cells and monocytes/macrophages. The direct binding of p50/p65 heterodimer to the TF-kB site in human TF promoter was demonstrated by p50 and p65 antibody ‘supershift’ using electrophoretic mobility shift assay and immunoprecipitation of the promoter of the human TF gene from chromatins of TNF-a-stimulated human umbilical vein endothelial cells. Andro-treated and p50 null mice both exhibited suppressed TF expression, blunted fibrin deposition, reduced venous thrombosis, and decreased neointimal hyperplasia. Blockade of TF activity by an anti-murine TF antibody also attenuated venous thrombosis and neointimal proliferation in vivo. Our findings thus indicate that NF-kB transcription factor p50 critically regulates TF activity in the pathogeneses of deep vein thrombosis and arterial restenosis, and suggest that specific inhibitors of p50, such as Andro, have the potential to be therapeutically valuable for preventing and perhaps treating arterial and venous thrombosis.