Chemocatalytic Cell Tagging Platform for Recording Cell-Cell Interactions via Engineered Palladium-Based Artificial...

Area of Science:

• Biochemistry
• Chemical Biology
• Immunology

Background:

• Proximity labeling platforms (PLPs) are crucial for studying spatial cell-cell interactions (CCIs).
• Existing PLPs often require genetic modifications or have limited light applicability.
• There is a need for versatile, non-genetic tools to probe CCIs.

Purpose of the Study:

• To develop a novel chemocatalytic proximity labeling approach for cell surface tagging.
• To engineer an artificial metalloenzyme (ArM) for efficient and specific labeling of CCIs.
• To demonstrate the utility of the ArM-Tag system in studying antigen-specific CCIs.

Main Methods:

• Development of the ArM-Tag system, integrating a palladium (Pd) cofactor, lipid anchor, and streptavidin (SAV) scaffold.
• Engineering of biotinylated Pd complexes and optimization of the ArM via directed evolution.
• Application of ArM-Tag to visualize CAR-T cell and tumor cell interactions via the mesothelin/anti-mesothelin axis.

Main Results:

• The ArM-Tag system successfully catalyzes O-deallylation on target cell surfaces.
• Short-lived electrophilic intermediates label neighboring cells within a micrometer range.
• Selective recording of antigen-specific CCIs, including CAR-T cell interactions with tumor cells, was achieved.

Conclusions:

• ArM-Tag offers a versatile, non-genetic method for probing cell-cell interactions.
• This platform has significant potential for advancing immunotherapy and targeted cancer therapies.
• The system provides a powerful tool for understanding immune cell-based therapies.