Estradiol-Responsive miR-365a-3p Interacts with Tissue Factor 3′UTR to Modulate Tissue Factor-Initiated Thrombin Generation

High estradiol (E2) levels are linked to an increased risk of venous thromboembolism; however, the underlying molecular mechanism(s) remain poorly understood. We previously identified an E2-responsive microRNA (miR), miR-494-3p, that downregulates protein S expression, and posited additional coagulation factors, such as tissue factor, may be regulated in a similar manner via miRs.To evaluate the coagulation capacity of cohorts with high physiological E2, and to further characterize novel E2-responsive miR and miR regulation on tissue factor in E2-related hypercoagulability.Ceveron Alpha thrombin generation assay (TGA) was used to assess plasma coagulation profile of three cohorts. The effect of physiological levels of E2, 10 nM, on miR expression in HuH-7 cells was compared using NanoString nCounter and validated with independent assays. The effect of tissue factor-interacting miR was confirmed by dual-luciferase reporter assays, immunoblotting, flow cytometry, biochemistry assays, and TGA.Plasma samples from pregnant women and women on the contraceptive pill were confirmed to be hypercoagulable (compared with sex-matched controls). At equivalent and high physiological levels of E2, miR-365a-3p displayed concordant E2 downregulation in two independent miR quantification platforms, and tissue factor protein was upregulated by E2 treatment. Direct interaction between miR-365a-3p and F3-3'UTR was confirmed and overexpression of miR-365a-3p led to a decrease of (1) tissue factor mRNA transcripts, (2) protein levels, (3) activity, and (4) tissue factor-initiated thrombin generation.miR-365a-3p is a novel tissue factor regulator. High E2 concentrations induce a hypercoagulable state via a miR network specific for coagulation factors.