USP25-mediated talin-1 stabilization in platelets: a novel mechanism of hyperreactivity and thrombosis risk during aging.

Aging is a critical risk factor for platelet hyperreactivity and thrombosis, yet the mechanisms involved remain poorly understood. This study investigates the role of ubiquitination in platelet function during aging. We identified heightened platelet reactivity in aged mice and human donors. Proteomic analysis of ubiquitin (Ub)-modified proteins and western blot revealed a reduction in overall ubiquitination in aged platelets, correlated with increased expression of deubiquitinating enzymes. Notably, ubiquitin specific peptidase 25 (USP25) was significantly upregulated in platelets from aged individuals. Functional assays indicated that USP25 deficiency impairs platelet function and delays arterial thrombus formation. Mechanistic investigations integrating Ub-modified proteomics and mass spectrometry demonstrated that USP25 enhances platelet hyperreactivity by stabilizing talin-1 through deubiquitination, maintaining its levels across various tissues, including the liver and spleen. Additionally, AZ1, a USP25/28 inhibitor, effectively suppressed platelet functions in both aged human and mouse models and decreased age-dependent platelet hyperreactivity and thrombus formation. Collectively, the findings delineate a remodeling of platelet ubiquitination during aging and establish USP25-mediated talin-1 stabilization as a key modulator of platelet hyperactivity in the older population.