Division of the Salmonella-containing vacuole and depletion of acidic lysosomes in Salmonella-infected host cells are novel strategies of Salmonella enterica to avoid lysosomes.
Salmonella has evolved several strategies to counteract intracellular microbicidal agents like reactive oxygen and nitrogen species. However, it is not yet clear how Salmonella escapes lysosomal degradation. Some studies have demonstrated that Salmonella can inhibit phagolysosomal fusion, whereas other reports have shown that the Salmonella-containing vacuole (SCV) fuses/interacts with lysosomes. Here, we have addressed this issue from a different perspective by investigating if the infected host cell has a sufficient quantity of lysosomes to target Salmonella. Our results suggest that SCVs divide along with Salmonella, resulting in a single bacterium per SCV. As a consequence, the SCV load per cell increases with the division of Salmonella inside the host cell. This demands more investment from the host cell to counteract Salmonella. Interestingly, we observed that Salmonella infection decreases the number of acidic lysosomes inside the host cell both in vitro and in vivo. These events potentially result in a condition in which an infected cell is left with insufficient acidic lysosomes to target the increasing number of SCVs, which favors the survival and proliferation of Salmonella inside the host cell.
Eswarappa
Sandeepa M
SM
Centre for Infectious Disease Research and Biosafety Laboratories, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore-560012, Karnataka, India.
Negi
Vidya Devi
VD
Chakraborty
Sangeeta
S
Chandrasekhar Sagar
B K
BK
Chakravortty
Dipshikha
D
D000818:Animals; D002460:Cell Line; D004705:Endocytosis; D006863:Hydrogen-Ion Concentration; D008247:Lysosomes / Q000382:microbiology* / Q000502:physiology*; D008264:Macrophages / Q000166:cytology / Q000276:immunology / Q000502:physiology; D051379:Mice; D009154:Mutation; D019779:Salmonella enterica / Q000502:physiology*; D014617:Vacuoles / Q000502:physiology*; D014638:Vanadates / Q000494:pharmacology
D014638:Vanadates