Conditionally Controlling Human TLR2 Activity via Trans-Cyclooctene Caged Ligands

Area of Science:

• Immunology
• Chemical Biology

Background:

• Toll-like receptors (TLRs) are crucial immune sensors.
• TLR activation timing and location influence immune response magnitude and outcome.
• Studying TLR signaling requires precise control over activation.

Purpose of the Study:

• To develop a novel molecular tool for controlled Toll-like receptor 2 (TLR2) activation.
• To investigate the impact of controlled TLR2 activation on immune signaling.
• To establish a versatile platform for studying TLR2-mediated immune responses.

Main Methods:

• Developed a synthetic TLR2/6 ligand with a bioorthogonal trans-cyclooctene (TCO) protecting group.
• Utilized "click-to-release" chemistry for conditional removal of the TCO group.
• Validated the system in RAW264.7 macrophages, murine primary immune cells, and human cell lines.

Main Results:

• The TCO-protected ligand was inactive until tetrazine addition.
• Conditional TCO removal restored agonist activity, leading to TLR2 activation.
• Demonstrated successful chemical control over TLR2 signaling in various immune cell models.

Conclusions:

• TCO-caging is a versatile strategy for creating chemically controllable TLR2 agonists.
• This approach allows for precise temporal control of TLR2 activation.
• Provides a new tool for dissecting complex immune signaling pathways.