Managing thrombus formation with EL2-5HTVac: A selective vaccination-based approach targeting the platelet serotonin 5-HT2AR.

Abstract

Cardiovascular disease is the leading global cause of death, largely attributable to thrombotic events that can result in conditions like myocardial infarction and stroke. The serotonin 2A receptor (5-HT_2AR) has been identified as a key mediator in platelet aggregation and thrombogenesis, making it a promising target for antithrombotic therapies. Current 5-HT_2AR antagonists, however, have been limited by nonselectivity and adverse effects. This study introduces a novel vaccine designed to target the ligand-binding domain of 5-HT_2AR, which resides in the second extracellular loop (EL2). This vaccine, referred to as "EL2-5HTVac," is expected to provide a long-lasting and selective therapeutic approach without the complications of increased bleeding risk. In this study, we demonstrate that EL2-5HTVac induces a robust immune response with a significant elevation in EL2-specific antibodies in comparison with the controls. Furthermore, vaccinated mice exhibited prolonged occlusion times in a FeCl₃-induced carotid artery thrombosis model without extending tail bleeding times, indicating a favorable safety profile. The EL2-5HTVac also effectively inhibited the serotonin-induced platelet shape change. Additionally, it also blocked serotonin-enhanced ADP-induced platelet aggregation, suggesting an ability to prevent serotonin-facilitated amplification of platelet activation. These findings suggest that EL2-5HTVac offers a dual advantage of thromboprotection and maintenance of hemostasis, potentially overcoming limitations of existing antithrombotic strategies. Future studies should focus on the long-term efficacy and safety of EL2-5HTVac, as well as the feasibility of a vaccination-based approach in larger animal models for eventual clinical application. SIGNIFICANCE STATEMENT: This study documents the utility of a vaccine as a potential antithrombotic agent. The vaccine can prevent thrombus formation without affecting hemostasis (causing bleeding).