Long Distance Signaling by Synthetic Cells

In a study published yesterday in Nature Chemical Biology, Rice researchers designed a set of transcriptional circuits that, when added to the genomes of single-cell microbes, allows the microbes to quickly form a network of local interactions to spur collective action. The findings could lead to engineered microbes that treat conditions in gut microbiomes or communicate with bioelectronics.

“Cells often use chemical signals to communicate and relay information to each other,” says senior author Matthew Bennett. “However, chemical signals have a limited range. After they leave the cell, they diffuse through whatever medium the cells are in, and that can only go so far. In this study, we looked at a previous system we built that uses two different strains and different types of communication between them to study how, once we increase the size of the colony containing these strains, it would react.”

According to Bennett, the cells had no problem communicating across small microfluidic chambers in previous experiments. “There, the diffusion of the signaling molecule is very fast, and basically global,” he says. “All the cells can talk to each other because it’s such a confined space. In our new system, that’s just not true. Cells can only talk to their close-by neighbors and have no way to communicate with those at the other end of the colony. Despite this, we found the oscillations generated by the circuits we put into these two strains are still able to synchronize across space and time.”

In fact, signals they thought would take several hours to travel from one end of the chamber to the other caused synchronous oscillations almost immediately.

“We figured out some factors that are important for that, types of feedback loops that increase synchronization across these large extended colonies,” he says. “This is important because, as synthetic biologists move toward engineering larger, multicellular systems, we must be able to control not just what goes on within a single cell but also coordinate what happens in space and time within the whole population.”