Capturing Cell-Cell Interactions via SNAP-tag and CLIP-tag Technology

Juxtacrine or contact-dependent signaling is a major form of cell communication in multicellular organisms. The involved cell-cell and cell-extracellular-matrix (ECM) interactions are crucial for the organization and maintenance of tissue architecture and function. However, because cell-cell contacts are relatively weak, it is difficult to isolate interacting cells in their native state to study, for example, how specific cell types interact with others (e.g., stem cells with niche cells) or where they locate within tissues to execute specific tasks. To achieve this, we propose artificial in situ cell-to-cell linking systems that are based on SNAP-tag and CLIP-tag, engineered mutants of the human O6-alkylguanine-DNA alkyltransferase. Here we demonstrate that SNAP-tag can be utilized to efficiently and covalently tether cells to poly(ethylene glycol) (PEG)-based hydrogel surfaces that have been functionalized with the SNAP-tag substrate benzylguanine (BG). Furthermore, using PEG-based spherical microgels as an artificial cell model, we provide proof-of-principle for inducing clustering that mimics cell-cell pairing.