The autophagy plays an important role in intracellular life of Francisella within Dictyostelium cells.

Autophagy or autophagocytosis is an evolutionally preserved catabolic process that involves the degradation of cytoplasmic components. During infection, various microorganisms regulate the autophagy process differently. Studies have shown that F. novicida in some cells stimulate autophagy, and in others suppress the autophagy process in favor of intracellular replication. Most of the studies were performed in mammalian cells, and very little is known about the autophagy process in the amoeba cell after infection with Francisella. It has been shown that in Dictyostelium, F. noatunensis subsp. noatunensis interacts with the autophagic machinery. There are no data about the role of autophagy of survival and replication of F. novicida and F. tularensis subsp. holarctica in Dictyostelium discoideum. In this study, we monitored the autophagy process in this social amoeba using different inducers and inhibitors of autophagy over infection with F. novicida and F. tularensis subsp. holarctica. The results have shown that treatment of cells with autophagy inhibitors, chloroquine and wortmannin has a negative effect on survival, replication and intracellular trafficking of both strains of Francisella. In contrast, induction of autophagy in amoebae cells results of high number of intracellular bacteria, successful replication in Francisella containing vacuole. We can conclude that the formation of an autophagic vacuole support the intracellular lifestyle of Francisella within Dictyostelium discoideum.