Hypoxia triggers collective aerotactic migration in Dictyostelium discoideum

Using a self-generated hypoxic assay, we show that the amoeba Dictyostelium discoideum displays a remarkable collective aerotactic behavior. When a cell colony is covered, cells quickly consume the available oxygen (O-2) and form a dense ring moving outwards at constant speed and density. To decipher this collective process, we combined two technological developments: porphyrin-based O-2-sensing films and microfluidic O-2 gradient generators. We showed that Dictyostelium cells exhibit aerotactic and aerokinetic response in a low range of O-2 concentration indicative of a very efficient detection mechanism. Cell behaviors under selfgenerated or imposed O-2 gradients were modeled using an in silico cellular Potts model built on experimental observations. This computational model was complemented with a parsimonious 'Go or Grow' partial differential equation (PDE) model. In both models, we found that the collective migration of a dense ring can be explained by the interplay between cell division and the modulation of aerotaxis.