Antidote-controlled DNA aptamer modulates human factor IXa activity.

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• Thrombosis is a major global health concern associated with high mortality and healthcare costs.
• Human factor IXa (HFIXa) is a key enzyme in thrombin generation, making it a significant target for anticoagulant therapies.

Purpose of the Study:

• To isolate and characterize novel DNA aptamers that specifically bind to HFIXa.
• To evaluate the anticoagulant potential of these aptamers and develop a safe, reversible therapeutic system.

Main Methods:

• Systematic evolution of ligands by exponential enrichment (SELEX) was employed to identify HFIXa-binding aptamers.
• Binding affinity, conformational analysis, and kinetic studies were performed.
• Anticoagulant activity was assessed by measuring the prolongation of activated partial thromboplastin time (aPTT).
• Aptamers were optimized through truncation and mutation, and drug-antidote pairs were designed.

Main Results:

• Two high-affinity DNA aptamers, seq 5 and seq 11, were identified with dissociation constants (K_d) of 74.07 ± 2.53 nM and 4.93 ± 0.15 nM, respectively.
• These aptamers dose-dependently prolonged aPTT, indicating anticoagulant activity.
• Optimized aptamer forms and rationally designed antidotes demonstrated effective anticoagulation and rapid reversal of the anticoagulant effect.

Conclusions:

• Novel DNA aptamers targeting HFIXa offer a promising avenue for anticoagulant therapy.
• The developed aptamer drug-antidote pairs provide a safe, controllable, and rapidly reversible anticoagulation strategy.
• This approach advances the development of novel antithrombotic agents.