Luminespib and AZ5104 are effective antithrombotic drugs via targeting the platelet Ero1α-PDI pathway

The platelet-surface Ero1α–protein disulfide isomerase (PDI) system is essential for integrin αIIbβ3 activation and platelet aggregation. Targeting the functional interplay between Ero1α and PDI emerges as a promising antithrombotic strategy. Using a tiered high-throughput screen, we identified two clinical-stage compounds, Luminespib and AZ5104, as selective inhibitors of the Ero1α-PDI interaction. They bind a hydrophobic pocket in the PDI b ʹ domain, inhibiting the pathway in biochemical and cellular assays without affecting other PDI family members. The antiplatelet effects of Luminespib and AZ5104 were abolished in megakaryocyte-specific Pdi or Ero1a knockout mice, confirming on-target specificity. Mechanistically, they concurrently inhibit Ero1α-PDI–driven extracellular integrin activation and intracellular Ca 2+ signaling. Both compounds potently reduced arterial thrombosis in mice without prolonging bleeding time. Our work establishes Luminespib and AZ5104 as clinical-stage antithrombotic agents that target the platelet Ero1α-PDI system, offering an effective strategy to achieve potent antithrombosis without compromising hemostasis.