Inactivation of
            <i>clpB</i>
            in the Pathogen Leptospira interrogans Reduces Virulence and Resistance to Stress Conditions

Lourdault, Kristel; Cerqueira, Gustavo M.; Wunder, Elsio A.; Picardeau, Mathieu

doi:10.1128/iai.05168-11

Cited by 96 publications

(101 citation statements)

References 36 publications

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“…Reduced virulence was achieved upon the inactivation of the gene encoding a putative outer membrane protease ClpB protein (34). Our identification of KatE as an additional virulence factor in Leptospira highlights both the dependence of this pathogen on a diverse repertoire of enzymes for survival and the requirement for a functional ROS resistance mechanism for full leptospiral pathogenesis.…”

Section: Discussionmentioning

confidence: 95%

Leptospira interrogans Catalase Is Required for Resistance to H ₂ O ₂ and for Virulence

et al. 2012

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h Pathogenic Leptospira spp. are likely to encounter higher concentrations of reactive oxygen species induced by the host innate immune response. In this study, we characterized Leptospira interrogans catalase (KatE), the only annotated catalase found within pathogenic Leptospira species, by assessing its role in resistance to H 2 O 2 -induced oxidative stress and during infection in hamsters. Pathogenic L. interrogans bacteria had a 50-fold-higher survival rate under H 2 O 2 -induced oxidative stress than did saprophytic L. biflexa bacteria, and this was predominantly catalase dependent. We also characterized KatE, the only annotated catalase found within pathogenic Leptospira species. Catalase assays performed with recombinant KatE confirmed specific catalase activity, while protein fractionation experiments localized KatE to the bacterial periplasmic space. The insertional inactivation of katE in pathogenic Leptospira bacteria drastically diminished leptospiral viability in the presence of extracellular H 2 O 2 and reduced virulence in an acute-infection model. Combined, these results suggest that L. interrogans KatE confers in vivo resistance to reactive oxygen species induced by the host innate immune response.

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Section: Discussionmentioning

confidence: 95%

Leptospira interrogans Catalase Is Required for Resistance to H ₂ O ₂ and for Virulence

et al. 2012

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“…Quantitation of transcript levels of selected genes. Many Leptospira genetic studies normalize to the endogenous flaB for gene expression analyses because it encodes a highly abundant protein that is synthesized under a variety of conditions (11,(37)(38)(39)(40). However, Leptospira spp.…”

Section: Resultsmentioning

confidence: 99%

Multiple Posttranslational Modifications of Leptospira biflexa Proteins as Revealed by Proteomic Analysis

Stewart

Carroll

Olano

et al. 2016

Appl Environ Microbiol

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cThe saprophyte Leptospira biflexa is an excellent model for studying the physiology of the medically important Leptospira genus, the pathogenic members of which are more recalcitrant to genetic manipulation and have significantly slower in vitro growth. However, relatively little is known regarding the proteome of L. biflexa, limiting its utility as a model for some studies. Therefore, we have generated a proteomic map of both soluble and membrane-associated proteins of L. biflexa during exponential growth and in stationary phase. Using these data, we identified abundantly produced proteins in each cellular fraction and quantified the transcript levels from a subset of these genes using quantitative reverse transcription-PCR (RT-PCR). These proteins should prove useful as cellular markers and as controls for gene expression studies. We also observed a significant number of L. biflexa membrane-associated proteins with multiple isoforms, each having unique isoelectric focusing points. L. biflexa cell lysates were examined for several posttranslational modifications suggested by the protein patterns. Methylation and acetylation of lysine residues were predominately observed in the proteins of the membrane-associated fraction, while phosphorylation was detected mainly among soluble proteins. These three posttranslational modification systems appear to be conserved between the free-living species L. biflexa and the pathogenic species Leptospira interrogans, suggesting an important physiological advantage despite the varied life cycles of the different species. Members of the genus Leptospira are spirochetal bacteria that share a conserved spiral morphology and motility. Leptospires can be broadly divided into host-associated species (including pathogens and the closely related intermediate species [1]) and free-living saprophytes, and Picardeau et al. proposed that the host-associated species may have evolved from a free-living progenitor (2). Therefore, comparisons between species with different ecological niches may elucidate the mechanisms that allow host-associated species to infect, persist in, and sometimes cause fatal disease in their hosts.Leptospira biflexa, a free-living saprophyte, was discovered over 100 years ago (3) and is often used as a model organism for studies of the genus as a whole (2, 4-6). Although host-associated species, such as Leptospira interrogans, are more intensively studied, they exhibit a low transformation efficiency that approaches the limits of detection. The higher in vitro growth rate and more efficient genetic tools available to manipulate L. biflexa make this organism better suited for laboratory studies. Techniques such as targeted allelic exchange, transposon mutagenesis, conjugative transfer, the use of fluorescent markers, and the use of an inducible promoter system were first developed in L. biflexa before use in L. interrogans (5, 7-9). However, despite its being a model organism, there are significant gaps in our knowledge of L. biflexa. No large-scale microarray data o...

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“…Knowledge of leptospiral pathogenesis is limited, but the development of a transposon (Tn) mutagenesis system has enabled the identification of factors essential for virulence (5), seven of which have been described: Loa22 (6), HemO (7), lipopolysaccharide (LPS) (8), motility (9,10), ClpB (11), KatE (12), and Mce (13). Further characterization of transposon mutants will advance the understanding of leptospiral pathogenesis and biology.…”

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confidence: 99%

Leptospiral Outer Membrane Protein LipL41 Is Not Essential for Acute Leptospirosis but Requires a Small Chaperone Protein, Lep, for Stable Expression

et al. 2013

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f Leptospirosis is a worldwide zoonosis caused by pathogenic Leptospira spp., but knowledge of leptospiral pathogenesis remains limited. However, the development of mutagenesis systems has allowed the investigation of putative virulence factors and their involvement in leptospirosis. LipL41 is the third most abundant lipoprotein found in the outer membranes of pathogenic leptospires and has been considered a putative virulence factor. LipL41 is encoded on the large chromosome 28 bp upstream of a small open reading frame encoding a hypothetical protein of unknown function. This gene was named lep, for LipL41 expression partner. In this study, lipL41 was found to be cotranscribed with lep. Two transposon mutants were characterized: a lipL41 mutant and a lep mutant. In the lep mutant, LipL41 protein levels were reduced by approximately 90%. Lep was shown through cross-linking and coexpression experiments to bind to LipL41. Lep is proposed to be a molecular chaperone essential for the stable expression of LipL41. The roles of LipL41 and Lep in the pathogenesis of Leptospira interrogans were investigated; surprisingly, neither of these two unique proteins was essential for acute leptospirosis.

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Inactivation of clpB in the Pathogen Leptospira interrogans Reduces Virulence and Resistance to Stress Conditions

Cited by 96 publications

References 36 publications

Leptospira interrogans Catalase Is Required for Resistance to H ₂ O ₂ and for Virulence

Leptospira interrogans Catalase Is Required for Resistance to H ₂ O ₂ and for Virulence

Multiple Posttranslational Modifications of Leptospira biflexa Proteins as Revealed by Proteomic Analysis

Leptospiral Outer Membrane Protein LipL41 Is Not Essential for Acute Leptospirosis but Requires a Small Chaperone Protein, Lep, for Stable Expression

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Inactivation of clpB in the Pathogen Leptospira interrogans Reduces Virulence and Resistance to Stress Conditions

Cited by 96 publications

References 36 publications

Leptospira interrogans Catalase Is Required for Resistance to H 2 O 2 and for Virulence

Leptospira interrogans Catalase Is Required for Resistance to H 2 O 2 and for Virulence

Multiple Posttranslational Modifications of Leptospira biflexa Proteins as Revealed by Proteomic Analysis

Leptospiral Outer Membrane Protein LipL41 Is Not Essential for Acute Leptospirosis but Requires a Small Chaperone Protein, Lep, for Stable Expression

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Leptospira interrogans Catalase Is Required for Resistance to H ₂ O ₂ and for Virulence

Leptospira interrogans Catalase Is Required for Resistance to H ₂ O ₂ and for Virulence