A Simple Approach to Probe the Extracellular Signaling Pathways Using Ligand Traps Available to Purchase

Cells communicate with one another through a huge variety of extracellular soluble signaling molecules. A common method in biology to investigate the signaling pathways is to inactivate the gene coding the interested ligand or receptor from cells using modern DNA technology, known as gene knockout. Even though very effective, however, gene knockout is a time-consuming and cost-prohibitive process and requires huge amount of efforts to conduct. Here we present a simple method to probe the extracellular signaling pathways through engineering a semi-permeable barrier between two cell populations. In this approach, ligand traps, receptor-coated nano/micro-particles, are embedded inside the nanoporous barrier. Because the receptors have the ability to selectively bind to certain ligand(s) with high affinity, the associated ligands can be ‘trapped’ inside the barrier when they try to perfuse from one cell population to the other. As a result, the targeted soluble ligands can be effectively blocked from the molecular exchange between the two cell populations. We have demonstrated the feasibility of this novel approach using fluorescent proteins. An analytical model has also been developed to guide the design of the ligand-trap-embedded barrier.