G6b-B antibody-based cis-acting platelet receptor inhibitors (CAPRIs) as a new family of anti-thrombotic therapeutics

Mazharian, A.; Bertin, O.; Sarkar, A.; Augros, J.; Bornert, A.; Loubiere, C.; Jönsson, F.; Warwicker, J.; Abbott, W. M.; Dushek, O.; Vayne, C.; Rauova, L.; Fütterer, K.; Rollin, J.; Poncz, M.; Senis, Y. A.

doi:10.1101/2024.05.10.593500

bioRxiv · 10.1101/2024.05.10.593500

G6b-B antibody-based cis-acting platelet receptor inhibitors (CAPRIs) as a new family of anti-thrombotic therapeutics

Mazharian, A.·Bertin, O.·Sarkar, A.·Augros, J.·Bornert, A.·Loubiere, C.·Jönsson, F.·Warwicker, J.·Abbott, W. M.·Dushek, O.·Vayne, C.·Rauova, L.·Fütterer, K.·Rollin, J.·Poncz, M.·Senis, Y. A.

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Abstract

Key PointsO_LIBispecific cis-acting platelet receptor inhibitors (CAPRIs) mediate hetero-clustering of the ITIM receptor G6B with ITAM receptors. C_LIO_LIG6B-GPVI and G6B-CD32A CAPRIs specifically inhibit collagen- and immune complex-induced thrombus formation, respectively. C_LI Platelets are highly reactive fragments of megakaryocytes that play a fundamental role in thrombosis and hemostasis. Predictably, all conventional anti-platelet therapies elicit bleeding, raising the question whether the thrombotic activity of platelets can be targeted separately. In this study, we describe a novel approach of inhibiting platelet activation through the use of bispecific single-chain variable fragments (bi-scFvs), termed cis-acting platelet receptor inhibitors (CAPRIs) that harness the immunoreceptor tyrosine-based inhibition motif (ITIM)-containing co-inhibitory receptor G6b-B (G6B) to suppress immunoreceptor tyrosine-based (ITAM)-containing receptor-mediated platelet activation. CAPRI-mediated hetero-clustering of G6B with either the ITAM-containing GPVI-FcR {gamma}-chain complex or Fc{gamma}RIIA (CD32A) inhibited collagen- or immune complex-induced platelet aggregation. G6B-GPVI CAPRIs strongly and specifically inhibited thrombus formation on collagen under arterial shear, whereas G6B-CD32A CAPRI strongly and specifically inhibited thrombus formation to heparin-induced thrombocytopenia, vaccine-induced thrombotic thrombocytopenia and antiphospholipid syndrome complexes on Von Willebrand Factor-coated surfaces and photochemical-injured endothelial cells under arterial shear. Our findings provide proof-of-concept that CAPRIs are highly effective at inhibiting ITAM receptor-mediated platelet activation, laying the foundation for a novel family of anti-thrombotic therapeutics with potentially improved efficacy and fewer bleeding outcomes compared with current anti-platelet therapies.

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Mazharian, A., Bertin, O., Sarkar, A., Augros, J., Bornert, A., Loubiere, C., Jönsson, F., Warwicker, J., Abbott, W. M., Dushek, O., Vayne, C., Rauova, L., Fütterer, K., Rollin, J., Poncz, M., Senis, Y. A.. 2024-05-14. G6b-B antibody-based cis-acting platelet receptor inhibitors (CAPRIs) as a new family of anti-thrombotic therapeutics. https://doi.org/10.1101/2024.05.10.593500

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