Resuscitation of Pseudomonas aeruginosa from dormancy requires hibernation promoting factor (PA4463) for ribosome preservation

Abstract

Significance The dormant subpopulations of Pseudomonas aeruginosa biofilms are linked to chronic infections because dormant cells tolerate antibiotic treatment and then repopulate the infections when conditions become favorable. Dormant cells must maintain cellular integrity, including preformed ribosomes, to resuscitate. The small-ribosome–binding proteins, ribosome modulation factor, and hibernation promoting factor (HPF) have evolved to maintain ribosomes in an inactive state. Using both population and single-cell–level studies, we show that HPF provides the primary mechanism used by P. aeruginosa to maintain ribosome integrity during dormancy, and that HPF is required for optimal P. aeruginosa resuscitation from dormancy. Preventing regrowth of the dormant subpopulation by targeting HPF may provide an effective means for eliminating the dormant subpopulations of P. aeruginosa infections.

Expression and regulation of the Pseudomonas aeruginosa hibernation promoting factor

“…Our prior transcriptomics analyses of P. aeruginosa biofilm subpopulations showed high abundance of mRNA encoding the HPF, in the dormant antibiotic‐tolerant subpopulation of cells (Williamson et al, ). A deletion of the hpf gene resulted in impaired recovery of starvation‐induced dormant cells, as well as loss of ribosomal RNAs in the starved cells (Akiyama et al, ). Those results demonstrated that HPF is required for ribosome protection in the dormant subpopulation of cells.…”

“…Binding of these factors causes formation of inactive 70S ribosomes, or inactive100S dimers (Vila-Sanjurjo et al, 2004;Kato et al, 2010), with YfiA competing with HPF, and forming an inactive 70S ribosome (Ueta et al, 2005). In P. aeruginosa PAO1, RMF does not appear to be required for recovery from starvation or for ribosome integrity during starvation (Akiyama et al, 2017). P. aeruginosa PAO1 does not encode a YfiA homolog.…”

Disassembly of theStaphylococcus aureushibernating 100S ribosome by an evolutionarily conserved GTPase

“…The 100S ribosome is ubiquitously found in all bacterial phyla and is important for bacterial survival during nutrient limitation (2-6), antibiotic stress (7), host colonization (8), dark adaptation (9), and biofilm formation (10,11). A common feature of these biological processes is that cells generally conserve energy by undergoing metabolic and translational dormancy because protein synthesis accounts for >50% of energy costs (12,13).…”

“…A common feature of these biological processes is that cells generally conserve energy by undergoing metabolic and translational dormancy because protein synthesis accounts for >50% of energy costs (12,13). The dimerization of 70S ribosomes has been shown to down-regulate translational efficiency in vivo (3) and in vitro (3,14), and bacteria lacking 100S ribosomes are prone to early cell death concomitant with rapid ribosome degradation (3,10,15,16). These studies lead to a model whereby the formation of the 100S complex sequesters the ribosome pool away from active translation, and 70S self-dimerization prevents ribosome degradation by an unknown pathway (3,17).…”

Shedding light into the mechanisms of formation and resuscitation of persistent bacterial cells

“…exponential phase of growth) have higher ribosome content than bacteria under growth-limiting conditions (i.e. stationary phase of growth; low nutrient conditions) (Nomura et al, 1984;Beste et al, 2005;Perez-Osorio et al, 2010;Akiyama et al, 2017). Additionally, the translational elongation rate and the number of active ribosomes decrease drastically during slow growth (Dai et al, 2016).…”