UNRAVELING THE ROLE OF RAB22A DURING DENDRITIC CELL INFECTION BY TOXOPLASMA GONDII

FACUNDO GARRIDO; FRANCO NIETO; SOFÍA DINAMARCA; LUIS S. MAYORGA; IGNACIO CEBRIÁN

San Juan

Congreso; XLI Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2023

Sociedad de Biología de Cuyo

Toxoplasma gondii is an obligate intracellular parasite and the causative agent of Toxoplasmosis, a worldwide spread disease. T. gondii has developed multiple strategies to infect most of nucleated warm blood animal cells including dendritic cells (DC). The parasite thrives within a specialized compartment known as the parasitophorous vacuole (PV), which serves as a protective niche for its survival and replication, enabling the parasite to evade host immune responses. Many interactions between the host cell and the PV have been described, but the molecular effectors involved in these connections and the outcome for the parasite growth and survival are still unknown. Previous works from our group have described the small GTPase Rab22a as a critical regulator of cross-presentation, including T. gondii-associated antigens. Rab22a is recruited to the T. gondii PV shortly after infection, but is not required for successful invasion. The main goal of this study is to elucidate the role of Rab22a in later stages of T. gondii infection within DCs. In this context, we show by immunofluorescence and confocal microscopy a sustained recruitment of Rab22a to the PV at 24, 48 and 72 hour post-infection. We silenced Rab22a expression in DCs by using a lentiviral vector containing a shRNA (Rab22a KD) and compared them to control DCs. We assessed the arrival of lipid droplets at the PV at 48 hours post-infection, as well as their quantity and size by fluorescent staining with the probe bodipy. Moreover, by using a fluorescent strain of the parasite and a flow cytometry-based approach, we determined that T. gondii is unable to replicate properly after 24 hours post-infection, suggesting an important role for Rab22a in late stages of the infection.