Effect of the deletion of prenylcysteine-oxidase 1 (PCYOX1) on arterial thrombosis in an animal model: Selected Abstract - SITeCS Congress 2022

Abstract

Prenylcysteine-oxidase1 (PCYOX1) enzyme, involved in the degradation of prenylated proteins, is expressed in different types of cells, among which vascular and blood cells. Previous studies demonstrated that the secretome of cells silenced for PCYOX1 reduced platelet adhesion on both fibrinogen and endothelial cells, suggesting its possible involvement in thrombotic mechanisms.  In this study we analyzed the role of PCYOX1 in arterial thrombosis by the use of an animal model. All the procedures have been carried on mice knock-out for PCYOX1 (Pcyox1KO) that were compared with wild-type (WT) mice. Arterial thrombosis was induced by Ferric chloride application on carotid artery, while pulmonary thromboembolism was induced by the injection of collagen-epinephrine. The phenotype and the functionality of platelets were analyzed by cytofluorimetry and functional tests. The expression of PCYOX1 on platelets was evaluated by mass spectrometry.  Thrombus formation induced by Ferric Chloride was reduced in Pcyox1KO mice, that were also protected from pulmonary thromboembolism. No differences were identified in blood cells count, vascular pro-coagulant activity and functional fibrinogen. Interestingly, Pcyox1KO mice displayed a marked reduction in the number of platelets-leukocytes aggregates, in the release of alpha granules, in the activation of receptor αIIbβ3 and in platelets aggregation induced by ADP e TRAP (analyzed on whole blood or platelets rich plasma). Mass spectrometry showed that PCYOX1 was highly expressed in WT platelets. However, the deletion of PCYOX1 did not alter platelets phosphorylation pathways, and platelets adhesion and aggregation (analyzed on washed platelets), in respect of WT mice. Of note, when platelets aggregation was performed on washed platelets isolated from WT mice in the presence of plasma derived from Pcyox1KO mice, we observed a strong impairment in comparison with the aggregation obtained on the same platelets resuspended in plasma derived from WT mice.  In conclusion, our results, showing an ipo-reactivity of platelets and a reduced arterial and pulmonary thrombosis in Pcyox1KO mice, suggest that this protein could represent a new potential target in antithrombotic therapy.