Fibrin-targeted and pH-responsive liposomes for synergistic thrombolysis and thrombotic microenvironment reprogramming

Abstract

Thrombolytic therapy, exemplified by tissue plasminogen activator, is often constrained by a short half-life, non-specific activity, and bleeding risks. To address these limitations, we developed tLipo@UA, a fibrin-targeted and pH-responsive liposomal system for the co-delivery of the urokinase-type plasminogen activator (uPA) and aspirin (acetylsalicylic acid, ASA). This system was functionalized with the CREKA (Cys-Arg-Glu-Lys-Ala) peptide for specific thrombus homing, and cholesteryl hemisuccinate (CHEMS) was incorporated to enable pH-sensitive drug release within the acidic thrombotic microenvironment. Experiments conducted both in vitro and in vivo demonstrated that tLipo@UA achieved efficient thrombus targeting and responsive drug release. The released uPA effectively dissolved thrombi, while the co-delivered ASA modulated the thrombotic microenvironment by suppressing the inflammatory cytokine release, thereby exhibiting synergistic thrombolytic and anti-inflammatory effects. Encapsulation of uPA significantly prolonged its circulation time and enhanced its localized efficacy. Furthermore, this system showed a favorable biosafety profile. Collectively, tLipo@UA presents a promising strategy for enhancing thrombolytic potency and achieving microenvironment reprogramming with reduced off-target risks, offering a rational design for dual-function drug carriers in the treatment of thrombotic diseases.