Structural and functional analyses of STM14_5441-STM14_5442: A potential mechanism for persister formation against aminoglycosides [resT RNA-seq]
The ability to eliminate bacterial persister cells is still a medical challenge that has yet to be overcome. These cells represent a unique subpopulation within bacterial communities and are characterized by a reduced susceptibility to antibiotics with growth retardation. In this study, we investigated the molecular basis of persister formation in Salmonella Typhimurium 14028s under aminoglycoside stress.We analyzed the crystal structure of the STM14_5441–STM14_5442 complex, which belongs to the type II toxin-antitoxin system, and identified key ribosome binding residues in STM14_5441. Changes in the antibiotic susceptibility of Salmonella caused by the loss of the ribosome binding property of STM14_5441 were assessed. We conducted intracellular ATP assays under aminoglycoside stress and RNA-seq analysis following STM14_5441 induction.Our studies demonstrated the critical role of STM14_5441 in the formation of persister cells in Salmonella, particularly those under aminoglycoside stress. We observed that a loss of ribosome binding in STM14_5441 resulted in increased antibiotic susceptibility. Additionally, intracellular ATP assays revealed increased ATP levels in bacterial persister cells, and RNA-seq analysis identified several genes that play a role in the formation of these persister cells.The present data suggest that persister forms under aminoglycoside stress through the following mechanisms: i) inhibition of membrane hyperpolarization by impeding F1Fo ATP synthase activity and ii) enhanced poststress recovery by ATP storage and increased protein synthesis capacity. Based on this suggestion, we reannotated the STM14_5441-STM14_5442 TA pair as the ResTA (RNA cleavage-induced energy storage toxin-antitoxin) system. Furthermore, new insights into the function of TA systems may lay the groundwork for developing novel strategies to target bacterial persister cells, thereby preventing the accelerated emergence of antibiotic resistance in bacterial populations. Overall design: To investigated the function of ResT, we established the strain harboring a plasmid with the STM14_5441 (resT) versus wild-type. We then performed gene expression profiling analysis using data obtained from RNA-seq of 2 different strains induced after 15 min. Comparative gene expression profiling analysis of RNA-seq data for wild-type and pBAD33::resT inducted strain (wild-type and pBAD33::resT inducted strain)