Pleiotropic Role of the RNA Chaperone Protein Hfq in the Human Pathogen Clostridium difficile

Boudry, Pierre; Gracia, Céline; Monot, Marc; Caillet, J.; Saujet, Laure; Hajnsdorf, Eliane; Dupuy, Bruno; Martin‐Verstraete, Isabelle; Soutourina, Olga

doi:10.1128/jb.01923-14

Cited by 72 publications

(126 citation statements)

References 103 publications

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“…2A). Low sporulation frequencies in C. difficile have been observed in other studies (1,63,64); however, the percentage of spore formation reported is widely variable, depending on the strain, medium, and methods used to enumerate spores (63). As shown in Fig.…”

Section: Identification Of Opp and App Transporters In C Difficilementioning

confidence: 83%

Conserved Oligopeptide Permeases Modulate Sporulation Initiation in Clostridium difficile

2014

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The anaerobic gastrointestinal pathogen Clostridium difficile must form a metabolically dormant spore to survive in oxygenic environments and be transmitted from host to host. The regulatory factors by which C. difficile initiates and controls the early stages of sporulation in C. difficile are not highly conserved in other Clostridium or Bacillus species. Here, we investigated the role of two conserved oligopeptide permeases, Opp and App, in the regulation of sporulation in C. difficile. These permeases are known to positively affect sporulation in Bacillus species through the import of sporulation-specific quorum-sensing peptides. In contrast to other spore-forming bacteria, we discovered that inactivating these permeases in C. difficile resulted in the earlier expression of early sporulation genes and increased sporulation in vitro. Furthermore, disruption of opp and app resulted in greater virulence and increased the amounts of spores recovered from feces in the hamster model of C. difficile infection. Our data suggest that Opp and App indirectly inhibit sporulation, likely through the activities of the transcriptional regulator SinR and its inhibitor, SinI. Taken together, these results indicate that the Opp and App transporters serve a different function in controlling sporulation and virulence in C. difficile than in Bacillus subtilis and suggest that nutrient availability plays a significant role in pathogenesis and sporulation in vivo. This study suggests a link between the nutritional status of the environment and sporulation initiation in C. difficile.

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Section: Identification Of Opp and App Transporters In C Difficilementioning

confidence: 83%

Conserved Oligopeptide Permeases Modulate Sporulation Initiation in Clostridium difficile

2014

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“…We failed to inactivate the gene encoding the PatB/MalY enzyme, probably because of its essentiality for C. difficile (51). Thus, to evaluate whether PatB/MalY is a cysteine desulfhydrase, we constructed a PatB/MalY-depleted strain using an antisense strategy (36,52). Compared to the strain carrying the control plasmid (Fig.…”

Section: Resultsmentioning

confidence: 99%

Control of Clostridium difficile Physiopathology in Response to Cysteine Availability

et al. 2016

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The pathogenicity of Clostridium difficile is linked to its ability to produce two toxins: TcdA and TcdB. The level of toxin synthesis is influenced by environmental signals, such as phosphotransferase system (PTS) sugars, biotin, and amino acids, especially cysteine. To understand the molecular mechanisms of cysteine-dependent repression of toxin production, we reconstructed the sulfur metabolism pathways of C. difficile strain 630 in silico and validated some of them by testing C. difficile growth in the presence of various sulfur sources. High levels of sulfide and pyruvate were produced in the presence of 10 mM cysteine, indicating that cysteine is actively catabolized by cysteine desulfhydrases. Using a transcriptomic approach, we analyzed cysteine-dependent control of gene expression and showed that cysteine modulates the expression of genes involved in cysteine metabolism, amino acid biosynthesis, fermentation, energy metabolism, iron acquisition, and the stress response. Additionally, a sigma factor (SigL) and global regulators (CcpA, CodY, and Fur) were tested to elucidate their roles in the cysteine-dependent regulation of toxin production. Among these regulators, only sigL inactivation resulted in the derepression of toxin gene expression in the presence of cysteine. Interestingly, the sigL mutant produced less pyruvate and H 2 S than the wild-type strain. Unlike cysteine, the addition of 10 mM pyruvate to the medium for a short time during the growth of the wild-type and sigL mutant strains reduced expression of the toxin genes, indicating that cysteine-dependent repression of toxin production is mainly due to the accumulation of cysteine by-products during growth. Finally, we showed that the effect of pyruvate on toxin gene expression is mediated at least in part by the two-component system CD2602-CD2601. Clostridium difficile is a Gram-positive spore-forming obligate anaerobe and the major cause of nosocomial diarrhea associated with antibiotic therapy. The symptoms of C. difficile infection (CDI) vary from mild diarrhea to life-threatening pseudomembranous colitis, a severe form of CDI (1). Virulent C. difficile strains produce two large toxins: an enterotoxin (TcdA) and a cytotoxin (TcdB). The tcdA and tcdB genes are clustered within a single chromosomal region, called the pathogenicity locus (PaLoc), with three accessory genes: tcdR, tcdE, and tcdC. The expression of the toxin genes is controlled through the coordinated action of the alternative sigma factor TcdR and its antagonist factor, TcdC (2-4). The tcdE gene encodes a holin-like protein that is required for toxin release (5).The spectrum of diseases caused by C. difficile depends on host factors and, for the severe forms, on the level of toxins produced, suggesting that the regulation of toxin synthesis is a critical determinant of C. difficile pathogenicity (6). Toxin production starts when C. difficile cultures enter the stationary growth phase (7) and is modulated in response to various environmental signals. Exposure to subinhibitory ...

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“…Hfq contributes to stress tolerance and pathogenicity in Listeria monocytogenes (22), Clostridium difficile (23) and other Gram positive bacteria (24). By contrast, deletion of Hfq from Bacillus subtilis and Staphylococcus aureus has almost no detectable phenotype (25, 26).…”

mentioning

confidence: 99%

Arginine Patch Predicts the RNA Annealing Activity of Hfq from Gram-Negative and Gram-Positive Bacteria

Zheng

Panja

Woodson

2016

Journal of Molecular Biology

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The Sm-protein Hfq facilitates interactions between small non-coding RNA (sRNA) and target mRNAs. In enteric Gram negative bacteria, Hfq is required for sRNA regulation, and hfq deletion results in stress intolerance and reduced virulence. By contrast, the role of Hfq in Gram positive is less established and varies among species. The RNA binding and RNA annealing activity of Hfq from Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes, Bacillus subtilis and Staphylococcus aureus were compared using minimal RNAs fluorescence spectroscopy. The results show that RNA annealing activity increases with the number of arginines in a semi-conserved patch on the rim of the Hfq hexamer and correlates with the previously reported requirement for Hfq in sRNA regulation. Thus, the amino acid sequence of the arginine patch can predict the chaperone function of Hfq in sRNA regulation in different organisms.

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Pleiotropic Role of the RNA Chaperone Protein Hfq in the Human Pathogen Clostridium difficile

Cited by 72 publications

References 103 publications

Conserved Oligopeptide Permeases Modulate Sporulation Initiation in Clostridium difficile

Conserved Oligopeptide Permeases Modulate Sporulation Initiation in Clostridium difficile

Control of Clostridium difficile Physiopathology in Response to Cysteine Availability

Arginine Patch Predicts the RNA Annealing Activity of Hfq from Gram-Negative and Gram-Positive Bacteria

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