INTERACTION OF MYCOBACTERIUM MARINUM AND THE AUTOPHAGIC PATHWAY

LERENA MARÍA CECILIA; GUTIERREZ MAXIMILIANO GABRIEL; ROMANO PATRICIA SILVIA; COLOMBO MARÍA ISABEL

Pinamar, Buenos Aires Argentina

Congreso; XLI Reunión Nacional de Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB); 2005

SAIB

Mycobacterium marinum (MM) is a natural pathogen of fish that occasionally affects humans causing the fish tank granuloma. These granulomas are very similar to the granulomas caused by M. tuberculosis in the lungs of humans. Its pathological similarity to M. tuberculosis infection and the more rapid growth and increased safety, makes MM a useful model to study pathogenic mycobacteria. Raw 267.4 cells infected with MM were analyzed by confocal microscopy. We have observed an increase in the processing of the protein LC3 upon infection with MM, which is indicative of autophagy. Our results indicate a high degree of colocalization between LC3 and MM phagosomes, implying an interaction between the autophagic pathway and MM. The analysis of bacteria survival was performed by determining the CFU (Colony Forming Units). Similar to M. tuberculosis we observed that when autophagy was induced, by incubation with starvation medium or by rapamycin treatment, there was a decrease on the survival of MM. Using electron microscopy, we observed a few phagosomes containing the bacteria, and an important number of multilamelar bodies. As previously described, we have also observed that after 15 hours infection, MM escapes from the phagosomes and develops actin tails in the cytoplasm. In summary, our results show for the first time that MM interacts with the autophagic pathway and that its survival is hampered by autophagy induction.