# Selective targeting of coagulation factor X Gla domain by negatively charged gold nanoparticles: a novel method for controlled antithrombotic therapy

## TL;DR

Researchers developed a new method using gold nanoparticles to selectively target a blood clotting protein, offering safer and more effective treatment for venous thromboembolism.

## Contribution

A novel nanoparticle-based approach that selectively targets the Gla domain of coagulation factor X to control antithrombotic therapy.

## Key findings

- Negatively charged 2–3 nm gold nanoparticles bind selectively to factor X's Gla domain.
- GNP binding induces conformational changes in FX, reducing its coagulation activity.
- GNPs prolonged clotting time in vitro and in vivo, demonstrating antithrombotic efficacy.

## Abstract

Venous thromboembolism (VTE) presents a significant global health burden due to its high incidence and potentially life-threatening complications. Although anticoagulants targeting vitamin K-dependent (VKD) factors, particularly factor X (FX), are widely employed, their efficacy is often limited by bleeding risks arising from off-target effects. Nanoparticle-based strategies, by contrast, enable precise and tunable modulation of protein activity through controlled adjustments in particle size, charge, and functionalization. In this work, we engineered negatively charged gold nanoparticles (GNPs) of defined sizes to selectively interact with the γ-carboxyglutamic acid (Gla) domain of VKD coagulation proteins. Using computational simulations, we systematically compared their binding conformations and affinities between GNPs and diverse VKD coagulation proteins, uncovering a size-dependent binding mechanism. This finding was subsequently validated through biochemical assays at both the molecular and cellular levels. Notably, GNPs with diameters of 2–3 nm demonstrated significantly higher affinity for FX compared to other VKD proteins, such as factor IX and protein C. This specific binding triggered substantial conformational changes in FX, diminishing its membrane-binding affinity. These structural alterations also reduced its enzymatic activity and impaired its activation efficiency within the coagulation cascade, thereby effectively attenuating the cascade by selectively modulating FX activity. Comprehensive in vitro coagulation assays and in vivo murine thrombosis models further validated that GNP treatment effectively prolonged coagulation time, demonstrating robust antithrombotic efficacy. Collectively, our results establish a novel nanoparticle-based therapeutic paradigm for targeting FX, offering an innovative and promising approach for enhancing the safety and efficacy of VTE prevention and management.

Image 1

•GNPs selectively bind VKDP Gla domain in a size-dependent manner.•Negatively charged GNPs (2–3 nm) exhibit strong affinity for FX.•GNPs induce FX conformational changes, disrupting coagulation activity.•GNPs prolong clotting time in vitro and in vivo, offering novel VTE therapy.

GNPs selectively bind VKDP Gla domain in a size-dependent manner.

Negatively charged GNPs (2–3 nm) exhibit strong affinity for FX.

GNPs induce FX conformational changes, disrupting coagulation activity.

GNPs prolong clotting time in vitro and in vivo, offering novel VTE therapy.