A modified CD9 tag for efficient protein delivery via extracellular vesicles

Area of Science:

• Biotechnology
• Nanomedicine
• Cell Biology

Background:

• Extracellular vesicles (EVs) show potential as diagnostic markers and therapeutic delivery vehicles, especially in oncology.
• Current methods for loading proteins into EVs, such as electroporation, have limitations including membrane damage and need for repeated purification, hindering clinical use.
• Efficient protein transfer and endosomal escape are critical for the clinical success of protein-based EV therapies.

Purpose of the Study:

• To develop a novel method for efficient protein transfer into EVs and enhance their endosomal escape for therapeutic applications.
• To overcome the limitations of current protein loading techniques for EVs, addressing clinical applicability challenges.

Main Methods:

• Engineered a short CD9 (sCD9)-INF/TAT tag to facilitate protein fusion with EVs and improve endosomal escape.
• Investigated protein transfer efficiency using the novel tag.
• Explored the impact of cell co-culture on protein transfer via EVs, assessing bystander effects.

Main Results:

• The sCD9-INF/TAT tag significantly enhanced the transfer of fused proteins into EVs.
• The engineered tag improved the endosomal escape of EVs after cellular uptake.
• Co-culturing EV producer and receptor cells dramatically increased protein transfer, suggesting bystander effects.

Conclusions:

• The sCD9-INF/TAT tag offers an efficient and natural method for protein loading into EVs, overcoming previous technical hurdles.
• This approach enhances therapeutic protein delivery and efficacy by improving endosomal escape.
• The method holds broad applicability for various therapeutic technologies, including cellular transplantation and viral therapy.