Recombinant Protein Micelles to Block Transduction by SARS-CoV-2 Pseudovirus

Area of Science:

• Biotechnology
• Nanomedicine
• Virology

Background:

• Emerging SARS-CoV-2 variants necessitate novel, adaptable therapeutic strategies.
• Current therapies face challenges in formulation and precise functionalization.
• Recombinant proteins offer a modular platform for developing targeted molecular therapies.

Purpose of the Study:

• To engineer self-assembling micellar nanostructures from recombinant oleosin proteins.
• To functionalize these nanostructures with mini-proteins capable of binding SARS-CoV-2 Spike S1 protein.
• To evaluate the efficacy of these nanostructures in blocking viral entry and explore their potential as multifunctional therapeutics.

Main Methods:

• Engineered recombinant oleosin proteins fused with SARS-CoV-2 S1-binding mini-proteins (LCBx).
• Expressed and purified Oleo-LCBx proteins in E. coli, verifying micelle formation (10-100 nm) via dynamic light scattering.
• Assessed the inhibition of wild-type and delta variant pseudovirus transduction in 293T-hsACE2 cells using Oleo-LCBx micelles.

Main Results:

• Oleo-LCB1 and Oleo-LCB3 micelles completely blocked viral transduction at 10 μM, reducing effective concentration to 5 nM.
• Oleo-LCB1 micelles demonstrated superior efficacy compared to synthetic LCB1 mini-proteins.
• Combinations of Oleo-LCB1 and Oleo-LCB3 exhibited enhanced antiviral activity, indicating multifunctionality.
• The developed micellar nanostructures were found to be non-toxic to human cells.

Conclusions:

• Recombinant oleosin self-assembles into effective nanostructures for delivering S1-binding mini-proteins.
• These modular micelles demonstrate potent and broad-spectrum inhibition of SARS-CoV-2 pseudoviruses.
• The tunable nature and multifunctionality of these nanostructures present a promising avenue for developing next-generation antiviral therapeutics.