Human PROS1 peptide

Background: Acquired protein S (PS) deficiency is highly associated with elevated circulating estrogen levels resulting from pregnancy, oral contraceptives, and estrogen replacement therapy; however, the mechanism of estrogen-mediated acquired PS deficiency remains poorly understood. Increasing evidence indicates that estrogen receptor signaling can indirectly modulate the expression of target genes at the post-transcriptional level by modulating the expression of microRNAs (miRNAs), and miRNAs have also been demonstrated to be involved in the regulation of hemostasis. Objectives: To investigate the mechanism of estrogen-mediated downregulation of PROS1 expression by the microRNA miR-494. Methods: Computational analyses of the PROS1 3'-untranslated region (UTR) were performed to identify putative miRNA-binding sites, and direct targeting of the PROS1 3'-UTR by miR-494 was determined with dual luciferase reporter assays in HuH-7 cells. Reporter vectors containing the PROS1 3'-UTR sequence with deleted miR-494-binding sites were also analyzed with luciferase reporter assays. The effects of estrogen on miR-494 and PROS1 mRNA levels in HuH-7 cells were determined by quantitative real-time PCR, and estrogen-mediated changes to secreted PS levels in culture supernatant of HuH-7 cells were measured with an ELISA. Results: The PROS1 3'-UTR sequence contains three putative miR-494-binding sites. miR-494 directly targets PROS1, and miR-494 levels are upregulated following estrogen treatment in HuH-7 liver cells in association with downregulated PROS1 mRNA and PS levels. Conclusions: The results from this study provide the first evidence for miRNA downregulation of PROS1 by miR-494, and suggest that miR-494 is involved in the mechanism of estrogen-mediated downregulation of PS expression.

Introduction: Venous bed specificity could contribute to differential vulnerability to thrombus formation, and is potentially reflected in mRNA profiles. Materials and methods: Microarray-based transcriptome analysis in wall and valve specimens from internal jugular (IJV) and saphenous (SV) veins collected during IJV surgical reconstruction in patients with impaired brain outflow. Multiplex antigenic assay in paired jugular and peripheral plasma samples. Results: Most of the top differentially expressed transcripts have been previously associated with both vascular and neurological disorders. Large expression differences of HOX genes, organ patterning regulators, pinpointed the vein positional identity. The "complement and coagulation cascade" emerged among enriched pathways. In IJV, upregulation of genes for coagulation inhibitors (TFPI, PROS1), activated protein C pathway receptors (THBD, PROCR), fibrinolysis activators (PLAT, PLAUR), and downregulation of the fibrinolysis inhibitor (SERPINE1) and of contact/amplification pathway genes (F11, F12), would be compatible with a thromboprotective profile in respect to SV. Further, in SV valve the prothrombinase complex genes (F5, F2) were up-regulated and the VWF showed the highest expression. Differential expression of several VWF regulators (ABO, ST3GAL4, SCARA5, CLEC4M) was also observed. Among other differentially expressed hemostasis-related genes, heparanase (HPSE)/heparanase inhibitor (HPSE2) were up-/down-regulated in IJV, which might support procoagulant features and disease conditions. The jugular plasma levels of several proteins, encoded by differentially expressed genes, were lower and highly correlated with peripheral levels. Conclusions: The IJV and SV rely on differential expression of many hemostasis and hemostasis-related genes to balance local hemostasis, potentially related to differences in vulnerability to thrombosis.