In vivo selection of synthetic nucleocapsids for tissue targeting

Area of Science:

• Biotechnology
• Nanomedicine
• Molecular Engineering

Background:

• Controlling the biodistribution of therapeutic nanoparticles is a significant challenge in medicine.
• In vivo library selection offers a powerful strategy for identifying biological constructs with specific tissue-homing capabilities.

Purpose of the Study:

• To develop and refine an in vivo library selection platform using self-assembling protein nanoparticles (synthetic nucleocapsids or synNCs).
• To identify novel synNC variants with improved biodistribution profiles for therapeutic applications.

Main Methods:

• Testing a low-diversity library of synNC surface mutations (45 variants).
• Screening a high-diversity library of synNCs displaying miniproteins (6.2 million variants) using in vivo selection.
• Evaluating the biodistribution of selected variants in vivo.

Main Results:

• No therapeutically relevant biodistribution changes were observed from the low-diversity surface mutation library.
• The high-diversity miniprotein display library successfully yielded variants that shifted accumulation towards the lungs and muscles within two rounds of selection.
• This demonstrates the efficacy of high-diversity screening for identifying targeted delivery constructs.

Conclusions:

• The developed in vivo library selection platform is effective for identifying protein nanoparticle variants with specific tissue-targeting capabilities.
• This approach holds promise for advancing targeted drug delivery and identifying ligands for various diseases.
• High-diversity libraries are crucial for discovering functional variants in complex biological systems.