OprD Repression upon Metal Treatment Requires the RNA Chaperone Hfq in Pseudomonas aeruginosa

Abstract

The metal-specific CzcRS two-component system in Pseudomonas aeruginosa is involved in the repression of the OprD porin, causing in turn carbapenem antibiotic resistance in the presence of high zinc concentration. It has also been shown that CzcR is able to directly regulate the expression of multiple genes including virulence factors. CzcR is therefore an important regulator connecting (i) metal response, (ii) pathogenicity and (iii) antibiotic resistance in P. aeruginosa. Recent data have suggested that other regulators could negatively control oprD expression in the presence of zinc. Here we show that the RNA chaperone Hfq is a key factor acting independently of CzcR for the repression of oprD upon Zn treatment. Additionally, we found that an Hfq-dependent mechanism is necessary for the localization of CzcR to the oprD promoter, mediating oprD transcriptional repression. Furthermore, in the presence of Cu, CopR, the transcriptional regulator of the CopRS two-component system also requires Hfq for oprD repression. Altogether, these results suggest important roles for this RNA chaperone in the context of environment-sensing and antibiotic resistance in P. aeruginosa.

Probing the sRNA regulatory landscape of P. aeruginosa: post‐transcriptional control of determinants of pathogenicity and antibiotic susceptibility

“…Loss of OprD leads to resistance to carbapenem in clinical isolates and enhanced fitness in animal infection models (Pirnay et al ., ; Wolter et al ., ; Skurnik et al ., ). It has been previously suggested that oprD is regulated at the post‐transcriptional level (Li et al ., ; Ducret et al ., ). PagL encodes a lipid A 3‐O‐deacylase.…”

“…Several previous studies have examined the regulatory mechanisms controlling the expression of OprD and suggesting a role for Hfq and an sRNA‐based regulatory mechanism. The transcription of the oprD gene is negatively regulated by two metal responsive two‐component systems (CzcRS and CopRS) and this regulatory effect requires the Hfq protein (Ducret et al ., ). Hfq appears to directly facilitate binding of the response regulator CzcR to the promoter of the oprD gene.…”

Harnessing Metabolic Regulation to Increase Hfq-Dependent Antibiotic Susceptibility in Pseudomonas aeruginosa

“…The transcript abundance of oprD , encoding a porin responsible for carbapenem uptake (Lynch et al, 1987 ) was 5-fold higher in PA14Δ hfq than in PA14 (Supplementary Table S2 ). It has been previously reported that Hfq negatively controls oprD expression indirectly on the transcriptional and directly on the post-transcriptional level via sRNAs (Ducret et al, 2016 ; Zhang et al, 2017 ), which can explain the increased susceptibility of the hfq deletion strains toward imipenem (Tables 1 , 2 , Supplementary Table S1 ). Moreover, the Hfq-Crc complex appears to repress translation of oprD mRNA directly (P. Pusic, unpublished).…”

Localization of all four ZnT zinc transporters in Dictyostelium and impact of ZntA and ZntB knockout on bacteria killing

“…Fe 2+ and Mn 2+ ) or by accumulating others, such as Cu 2+ and Zn 2+ , to intoxicating concentrations (Flannagan et al, 2015;Lopez and Skaar, 2018). On the pathogen side, bacteria have evolved several strategies to survive excess of metal ions, both in the environment (Ducret et al, 2016;Gonzalez et al, 2018) and in contact with phagocytes (Botella et al, 2011). For instance, metal efflux transporters, such as cation diffusion facilitators and P-type ATPases, remove excess ions from the bacterial cytoplasm (Chan et al, 2010;Kolaj-Robin et al, 2015).…”