Targeting α6β1 Integrin Signaling with Pranlukast to Modulate Venous Endothelium Function and Reduce Post-Thrombotic Vein Wall Injury.

Background

Post-thrombotic syndrome (PTS) develops in 20-50% of patients following deep vein thrombosis (DVT) due to persistent vein wall injury, inflammation, and fibrotic remodeling. Current anticoagulant therapies do not directly address PTS pathogenesis and carry bleeding risks. We characterized the extracellular matrix (ECM) components and evaluated whether pharmacological inhibition of α6β1 integrin with pranlukast (PLK) could modulate post-thrombotic vein wall injury in a preclinical DVT model.

Methods

ECM protein composition was characterized in C57BL/6 mice by western blotting of IVC harvested after IVC ligation from 4 to 21 days, identifying the laminin-α6β1 integrin axis as a therapeutic target. Presence of α6β1 was confirmed via immunofluorescence in post-thrombotic mice up to 21 days. Pranlukast (PLK), a candidate α6β1 integrin antagonist, was tested in vitro and in vivo. Venous endothelial cells were treated with PLK to assess transcription of integrins (Itga6, Itgb1) and inflammation markers (sele). In vivo, C57BL/6 mice received PLK or vehicle before and after IVC ligation. Thrombus characteristics, vein wall remodeling, integrin protein expression, and cellular composition were evaluated.

Results

Laminin, fibrin, thrombomodulin, and fibronectin were present in the post-thrombotic IVC in mice. The ECM protein laminin and its primary receptor, α6β1 integrin (CD49f/CD29), were highly expressed up to 21 days post-thrombosis in the vein wall. In vitro, PLK treatment significantly decreased transcription of Itga6, Itgb1, and sele after 24 hours. PLK did not affect thrombus formation, with comparable thrombus weights and lengths across groups, demonstrating a safety profile. The administration of PLK was associated with decreased levels of α6 and β1 integrins in the vein wall and thrombus, but also with a significant reduction in vein wall thickness (VWT) (PLK: 44.95 μm ±5.09, DMSO: 56.84 μm ±6.54, p=0.0081) at 8 days and in proinflammatory monocytes (CCR2+) compared to control (PLK: 14.73 ±1.69, DMSO: 23.15 ±2.38, p<0.0001).

Conclusions

This study demonstrates that targeting α6β1 integrin with PLK reduces vein wall fibrotic injury following experimental DVT without altering thrombus formation. These findings identify a novel, non-anticoagulant therapeutic strategy for PTS prevention that warrants further investigation in chronic models and translational studies.