1,25-Dihydroxyvitamin D3 suppresses inflammation-induced expression of plasminogen activator inhibitor-1 by blocking nuclear factor-κB activation

Plasminogen activator inhibitor (PAI)-1 is a major fibrinolytic inhibitor. High PAI-1 is associated with increased renal and cardiovascular disease risk. Previous studies demonstrated PAI-1 down-regulation by 1,25-dihydroxyvitamin D-3 (1,25(OH)(2)D-3), but the molecular mechanism remains unknown. Here we show that exposure of mouse embryonic fibroblasts to TNF alpha or LPS led to a marked induction of PAI-1, which was blunted by 1,25(OH)(2)D-3, NF-kappa B inhibitor or p65 siRNA, suggesting the involvement of NF-kappa B in 1,25(OH)(2)D-3-induced repression. In mouse Pai-1 promoter a putative cis-kappa B element was identified at -299. EMSA and ChIP assays showed that TNE-alpha increased p50/p65 binding to this kappa B site, which was disrupted by 1,25(OH)(2)D-3. Luciferase reporter assays showed that PAI-1 promoter activity was induced by TNF alpha or LPS, and the induction was blocked by 1,25(OH)(2)D-3. Mutation of the kappa B site blunted TNF alpha, LPS or 1,25(OH)(2)D-3 effects. 1,25(OH)(2)D-3 blocked 1 kappa B alpha degradation and arrested p50/p65 nuclear translocation. In mice LPS stimulated PAI-1 expression in the heart and macrophages, and the stimulation was blunted by pre-treatment with a vitamin D analog. Together these data demonstrate that 1,25(OH)(2)D-3 down-regulates PAI-1 by blocking NE-kappa B activation. Inhibition of PAI-1 production may contribute to the reno- and cardio-protective effects of vitamin D. (C) 2010 Elsevier Inc. All rights reserved.