A two-step model of cell cycle-linked metacyclogenesis in Trypanosoma cruzi

The causative protozoan of Chagas disease, Trypanosoma cruzi, undergoes a complex life cycle involving cell cycle regulation and differentiation. However, the connection between these processes remains unclear. Here, we investigated the cell cycle phase in which commitment to metacyclogenesis occurs. Using synchronized populations, CFSE labeling, and cytokinesis inhibition, we show that differentiation stimuli can be perceived from G2/M to G1, but execution takes place exclusively in G1. CFSE results revealed that parasites already in G1 differentiate without division, whereas inhibition of cytokinesis assays demonstrated that post-G1 cells must complete cytokinesis before producing metacyclics. Together, these findings support a two-step model, stimulus perception followed by execution in G1, providing new insights into T. cruzi differentiation and advancing our understanding of parasite development and transmission.