Breaking the membranous refuge of intracellular bacteria

forthcoming

Many clinically important pathogens invade human cells and evade their intrinsic defenses by hiding within pathogen-containing vacuoles (PCVs). Hence, it may be feasible to combat such microbes by deliberately destabilizing their PCVs. To promote progress towards such an innovative therapeutic concept, I propose a 5-year research program in which my team will generate a molecular mechanistic understanding of how the PCV is maintained, how it can be destabilized, and how the consequences of PCV destabilization can be steered towards a beneficial outcome. We will focus on the inclusion, i.e., the PCV of Chlamydia trachomatis, as the strong host cell dependence of this leading bacterial cause of ocular and urogenital infections makes it an exquisite target for pioneering PCV-destabilizing strategies. In AIM 1, we will leverage inclusion-destabilizing conditions we identified previously and state-of-the-art proteomic, lipidomic, and microscopic approaches to address the fundamental question of what distinguishes unstable from stable inclusions. In AIM 2, we will build on these findings and apply our unique microscopic reporters for inclusion damage and a robust genetic approach to identify the molecular basis of inclusion stability, determine how distinct forms of inclusion destabilization interact with each other and with host cellular defense programs, and find ways to steer the outcome towards either host cell death or survival. Finally, in AIM 3, we will clarify which of those two outcomes therapeutic targeting should aim for by isolating cells cured from infection via inclusion destabilization, followed by systematic cell biological and omics investigations to determine if infection causes long-lasting damage to host cells. By filling critical knowledge gaps in the field of host-pathogen interactions, I expect this project to pave the way for the future design of innovative precision antibiotics for our battle against intracellular infections.