A recent study has reshaped our understanding of how thrombosis develops under inflammatory and infectious conditions. Researchers have identified a soluble form of tissue factor (sTF) that directly mediates blood coagulation during necroptosis, a regulated form of cell death often triggered by severe inflammation or viral infections. The findings bridge key gaps in our knowledge of coagulation biology and point to novel therapeutic targets that could prevent thrombosis without compromising normal hemostasis.
Tissue factor has long been known as a membrane-bound initiator of the coagulation cascade, activating clot formation when vascular injury occurs. However, this study challenges the long-standing view that only the full-length, membrane-anchored TF (flTF) is functional in coagulation. Using a combination of biochemical, genetic, and in vivo approaches, the research team demonstrated that during necroptosis, proteases from the ADAM family cleave flTF, releasing a fully functional soluble TF into the bloodstream.
This soluble TF was shown to drive thrombosis independently of membrane TF, a finding that overturns decades of assumptions. The authors generated an sTF-specific antibody and engineered knock-in mice resistant to ADAM cleavage (mutations at T211V212→E211E212). In hese models, blocking sTF production completely prevented necroptosis-related thrombosis during inflammatory and vitral challenges. Conversely, inhibition of necroptosis or ADAM activity abrogated sTF generation, confirming its mechanistic link to this pathway.
The study detected elevated sTF levels in the plasma of COVID-19 patients and demonstrated that infection with a SARS-CoV-2 pseudovirus can induce sTF formation in human monocytes. This suggests that sTF may be a key driver of the coagulopathy and thrombotic complications frequently observed in severe viral infections.
Beyond its mechanistic significance, the discovery holds diagnostic and therapeutic promise. The currently used thrombosis marker, D-dimer, reflects fibrin breakdown. In contrast, sTF appears upstream in the coagulation cascade and may serve as an early biomarker of thrombus initiation. Moreover, because sTF production depends on necroptosis and ADAM protease activity, targeting these pathways could selectively inhibit pathological thrombosis while sparing physiological clotting functions.