Dataset Information

Post-translational modification of LipL32 during Leptospira interrogans infection.

ABSTRACT:

Background

Leptospirosis, a re-emerging disease of global importance caused by pathogenic Leptospira spp., is considered the world's most widespread zoonotic disease. Rats serve as asymptomatic carriers of pathogenic Leptospira and are critical for disease spread. In such reservoir hosts, leptospires colonize the kidney, are shed in the urine, persist in fresh water and gain access to a new mammalian host through breaches in the skin.

Methodology/principal findings

Previous studies have provided evidence for post-translational modification (PTM) of leptospiral proteins. In the current study, we used proteomic analyses to determine the presence of PTMs on the highly abundant leptospiral protein, LipL32, from rat urine-isolated L. interrogans serovar Copenhageni compared to in vitro-grown organisms. We observed either acetylation or tri-methylation of lysine residues within multiple LipL32 peptides, including peptides corresponding to regions of LipL32 previously identified as epitopes. Intriguingly, the PTMs were unique to the LipL32 peptides originating from in vivo relative to in vitro grown leptospires. The identity of each modified lysine residue was confirmed by fragmentation pattern analysis of the peptide mass spectra. A synthetic peptide containing an identified tri-methylated lysine, which corresponds to a previously identified LipL32 epitope, demonstrated significantly reduced immunoreactivity with serum collected from leptospirosis patients compared to the peptide version lacking the tri-methylation. Further, a subset of the identified PTMs are in close proximity to the established calcium-binding and putative collagen-binding sites that have been identified within LipL32.

Conclusions/significance

The exclusive detection of PTMs on lysine residues within LipL32 from in vivo-isolated L. interrogans implies that infection-generated modification of leptospiral proteins may have a biologically relevant function during the course of infection. Although definitive determination of the role of these PTMs must await further investigations, the reduced immune recognition of a modified LipL32 epitope suggests the intriguing possibility that LipL32 modification represents a novel mechanism of immune evasion within Leptospira.

SUBMITTER: Witchell TD

PROVIDER: S-EPMC4214626 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature

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Publications

Post-translational modification of LipL32 during Leptospira interrogans infection.

Witchell Timothy D TD Eshghi Azad A Nally Jarlath E JE Hof Rebecca R Boulanger Martin J MJ Wunder Elsio A EA Ko Albert I AI Haake David A DA Cameron Caroline E CE

PLoS neglected tropical diseases 20141030 10

<h4>Background</h4>Leptospirosis, a re-emerging disease of global importance caused by pathogenic Leptospira spp., is considered the world's most widespread zoonotic disease. Rats serve as asymptomatic carriers of pathogenic Leptospira and are critical for disease spread. In such reservoir hosts, leptospires colonize the kidney, are shed in the urine, persist in fresh water and gain access to a new mammalian host through breaches in the skin.<h4>Methodology/principal findings</h4>Previous studie ...[more]

PMID: 25356675

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Project description:Pathogenic species of Leptospira are the causative agents of leptospirosis, a zoonotic disease that causes mortality and morbidity worldwide. The understanding of the virulence mechanisms of Leptospira spp is still at an early stage due to the limited number of genetic tools available for this microorganism. The development of random transposon mutagenesis in pathogenic strains a decade ago has contributed to the identification of several virulence factors. In this study, we used the transposon sequencing (Tn-Seq) technique, which combines transposon mutagenesis with massive parallel sequencing, to study the in vivo fitness of a pool of Leptospira interrogans mutants. We infected hamsters with a pool of 42 mutants (input pool), which included control mutants with insertions in four genes previously analyzed by virulence testing (loa22, ligB, flaA1, and lic20111) and 23 mutants with disrupted signal transduction genes. We quantified the mutants in different tissues (blood, kidney and liver) at 4 days post-challenge by high-throughput sequencing and compared the frequencies of mutants recovered from tissues to their frequencies in the input pool. Control mutants that were less fit in the Tn-Seq experiment were attenuated for virulence when tested separately in the hamster model of lethal leptospirosis. Control mutants with unaltered fitness were as virulent as the wild-type strain. We identified two mutants with the transposon inserted in the same putative adenylate/guanylate cyclase gene (lic12327) that had reduced in vivo fitness in blood, kidney and liver. Both lic12327 mutants were attenuated for virulence when tested individually in hamsters. Growth of the control mutants and lic12327 mutants in culture medium were similar to that of the wild-type strain. These results demonstrate the feasibility of screening large pools of L. interrogans transposon mutants for those with altered fitness, and potentially attenuated virulence, by transposon sequencing.

Dataset Information

Post-translational modification of LipL32 during Leptospira interrogans infection.

Background

Methodology/principal findings

Conclusions/significance

Publications

Post-translational modification of LipL32 during Leptospira interrogans infection.

Similar Datasets

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