Huge Modification of the Cell Theory by the Recent Discovery of the Widespread Cell-Derived Extracellular Vesicles ^†

The aim of this work is to discuss the necessity to strongly modify the powerful well-acknowledged cell theory by taking into account the recently discovered universal cell-derived extracellular vesicles (EVs). In a great breakthrough, EVs are now known to mediate important cell interconnections, with many still unknown mechanisms. There is a missing step between the accumulated biological knowledge about EVs during the past two decades and the many recent preclinical searches, dealing with a few human patients compared to controls, for the applications of EVs in oncology. In this case, the huge amount of different cell-derived EVs generates an inextricable complexity. To evidence unknown EV-mediated mechanisms, a simple cell model would be much more convenient. The microorganism Dictyostelium discoideum (Dd) is ideal to achieve this goal as a wonderful eukaryotic in vitro and in vivo cell model. In 1998, we discovered Dd EVs to be involved in mediating a new multidrug resistance mechanism, and also the normal and physiological release of different EVs during the well-separated growth and starvation-induced differentiation of Dd cells. Moreover, Dd cells have many other advantageous characteristics. Axenic Dd cells are very well suited for conditioned-medium experiments to study the influence of specifically generated Dd EVs upon naive Dd cells, as will be shown in this presentation.