Generation of species cross-reactive aptamers using "toggle" SELEX

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• Species cross-reactivity is crucial for evaluating therapeutic molecules in animal models.
• Developing ligands that bind to targets across different species presents a significant challenge.
• Thrombin plays a vital role in hemostasis, making it a key target for anticoagulants.

Purpose of the Study:

• To develop an in vitro selection strategy for identifying RNA ligands (aptamers) with cross-species reactivity.
• To isolate aptamers that bind to both human and porcine thrombin.
• To assess the therapeutic potential of cross-reactive aptamers.

Main Methods:

• An in vitro selection strategy termed "toggle" selection was employed.
• Alternating rounds of selection targeted human and porcine thrombin.
• RNA ligands were screened for high-affinity binding to both species' thrombin.

Main Results:

• A family of RNA aptamers that bind both human and porcine thrombin with high affinity was successfully selected.
• The aptamer Toggle-25 demonstrated inhibition of plasma clot formation and platelet activation.
• The toggle strategy proved effective in generating cross-reactive aptamers.

Conclusions:

• The toggle selection strategy is a simple and effective method for promoting cross-species reactivity in aptamer development.
• This approach facilitates the isolation of ligands with desired properties for therapeutic and diagnostic applications.
• The strategy is potentially generalizable to other proteins and combinatorial library screening methods.