Lipids Droplets Play an Important Role During Obligate Intracellular Bacterial Infections
Context: Lipid droplets (LDs) are cytoplasmic lipid storage organelles that have recently gained importance in host-pathogen interactions. Surrounded by a phospholipid monolayer, they store excess cellular free fatty acids and cholesterol as triacylglycerol and cholesterol ester, respectively. LDs are crucial to lipid metabolism, energy homeostasis, cell signaling, and inflammation, making them a prime target for pathogens. Several bacterial, viral, and protozoal pathogens exploit host- or self-derived LDs to build infectious progeny and/or modulate inflammation to promote infection. However, the diverse role of LDs in different bacterial pathogens remains elusive and merits in-depth elucidation. Objective: Our goal is to summarize the current research describing how certain bacterial pathogens manipulate LDs and how those LDs affect bacterial survival and infectivity. Methods/Design: We explored literature from the last ten years involving LD-pathogen interactions for the obligate intracellular pathogens Chlamydia trachomatis (Ct), Chlamydia pneumoniae (Cp), Coxiella burnetii (Cb), Anaplasma phagocytophilium (Ap), Ehrlichia chaffeensis (Ec), and Orientia tsutsugamushi (Ot). Results: Ct aggregates host LDs in the inclusion membrane which is speculated to be the bacterium’s nutrient source. Alternatively, there are no studies yet describing the relation between LDs and Cp,; however, this bacterium does show lipid dysregulation and production of pro-inflammatory cytokines during LD-rich foamy macrophage formation. Further, the tick-borne pathogens Ap and Ec use host-derived lipids for cell wall biosynthesis. Whereas, Ot and Cb manipulate LDs for survival. Conclusion: Our review sheds light on how obligate intracellular pathogens utilize LDs to promote survival in host cells. Since LDs are important metabolic organelles, focusing on their role will help us understand cellular metabolic processes important during host-pathogen interactions.
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"Lipids Droplets Play an Important Role During Obligate Intracellular Bacterial Infections" (2018). MU-COM Research Day. 93.