Huddle! Cells secret communication clusters

Cells cluster together to communicate within restricted groups, just like a sports team huddle discusses secret tactics, say scientists from the European Molecular Biology Laboratory (EMBL). Using developing zebrafish, scientists showed that the way cells organise themselves influences their ability to communicate. This strategy could affect processes like wound repair, organ formation and cancer. “Everybody can speak, everybody can listen, but what’s said in the group stays in the group,” said PhD student Sevi Durdu. “By huddling together, these cells trap and concentrate a signal to communicate only amongst themselves.” Durdu focused on a group of cells that will become the zebrafish’s lateral line – organs along its flank which sense changes in water pressure. This mass of cells move along the developing animal’s side until it reaches a point where these organs should form. A group then stops, huddles together before developing to the organ, while the rest of the mass moves on, until they stop, form another organ and so on. Huddling cells change shape from flat crawling cells to upright, tear shaped ones that cluster like a clove of garlic. Trapped within this shape, is FGF, a molecule cells use to communicate. “Normally, FGF acts as a long-range communication signal. In the lateral line, we find most of this signal is normally just wafting over the cells’ heads,” said Darren Gilmour, Durdu’s supervisor. “But when the cells get together and huddle they can trap and concentrate this signal in their shared lumen, and make a decision others can’t; they stop moving.” By enabling a group of cells to increase the concentration of FGF they are in contact with, scientists found the shared lumen plays a critical role in determining when and where the huddle stops. Increased FGF meant cell huddles came to a standstill more abruptly and organs were spaced closely. “All epithelial cells – and that’s the cells that make up most of the organs in our bodies – can do this, so you could imagine that this type of local chamber could be forming transiently in many different parts of the body, whenever cells need to self-organise and communicate,” said Gilmour Breaking the huddle leads to FGF leaking, meaning effective communication is ruined, leading the scientists to wonder if this mechanism played a role in wound repair. When the skin is broken, upright cells lie down and start crawling, huddles break and cells change their behaviour. Future work will focus on understanding the relationship between the ability to stop, and signals previously found to drive cells forward, and how they are influenced by changed in cell shape. Luminal signalling links cell communication to tissue architecture during organogenesis Hear more about the work in this video http://youtu.be/qgAwNqPUiPY