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Ashaiba A, Arun A, Prasad KS, Tellis RC. A clinical pilot study for the detection of sphingomyelinase in leptospirosis patient's urine at tertiary care hospital. Heliyon 2023; 9:e21138. [PMID: 37916114 PMCID: PMC10616390 DOI: 10.1016/j.heliyon.2023.e21138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 11/03/2023] Open
Abstract
Purpose Leptospirosis is a perplexing mystification for many clinicians. Clinically often underdiagnosed due to lack of a rapid, sensitive, and specific diagnostic test. Currently available diagnostic tests have their own limitations; therefore, monitoring biomarkers that contribute an essential role in pathogenesis is crucial. Herein, a pilot study was conducted to detect the presence of sphingomyelinase in urine of leptospirosis patients. Methods Blood and urine samples were collected from 140 patients having febrile illness. Samples were analyzed through culturing, dark-field microscopy, detecting anti-leptospiral antibodies by MAT, IgM ELISA, Leptocheck-WB and screening for sphingomyelinase using a sphingomyelinase assay kit. Results Out of 140 febrile illness patients, 22.14 % were tested leptospirosis, 33.57 % were dengue, 25 % scrub typhus, 18.57 % malaria and 0.71 % co-infection (dengue-leptospirosis). MAT seropositivity of 19.28 % (27/140) was confirmed with the highest agglutinant determined against serovar Icterohaemorrhagiae RGA followed by Autumnalis, Australis, and Pyrogens. IgM ELISA and Leptocheck-WB positivity was 16.42 % and 13.57 % respectively. Whereas culture and dark-field microscopy showed a sensitivity of 4.28 % and 2.1 %, respectively. Out of 31 confirmed cases of leptospirosis, sphingomyelinase was detected in the urine of 25 (80.64 %) patients, MAT positivity was seen in 87.09 % and culture positivity was seen in 12.90 % of cases. Conclusion Detection of sphingomyelinase in the urine of a leptospirosis patient and its absence in other febrile illnesses like dengue, malaria and scrub typhus establish evidence of secretion of sphingomyelinase in urine during leptospiral infection. Hence, sphingomyelinase could be used as a potential diagnostic biomarker to detect leptospirosis in a non-invasive way.
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Affiliation(s)
- A. Ashaiba
- Department of Microbiology, Yenepoya Medical College, Yenepoya (Deemed to be University), Deralakatte, Mangalore, 575 018, India
- Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore, 575 018, India
| | - A.B. Arun
- Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore, 575 018, India
- Yenepoya Institute of Arts, Science, Commerce and Management (YIASCM), Yenepoya (deemed to be) University, Mangalore, 575 002, India
| | - K. Sudhakara Prasad
- Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore, 575 018, India
- Nanomaterial Research Laboratory, Yenepoya Research Centre Yenepoya (Deemed to be University), Deralakatte, Mangalore, 575 018, India
| | - Rouchelle C. Tellis
- Department of Microbiology, Yenepoya Medical College, Yenepoya (Deemed to be University), Deralakatte, Mangalore, 575 018, India
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Ataides LS, de Moraes Maia F, Conte FP, Isaac L, Barbosa AS, da Costa Lima-Junior J, Avelar KES, Rodrigues-da-Silva RN. Sph2 (176-191) and Sph2 (446-459): Identification of B-Cell Linear Epitopes in Sphingomyelinase 2 (Sph2), Naturally Recognized by Patients Infected by Pathogenic Leptospires. Vaccines (Basel) 2023; 11:vaccines11020359. [PMID: 36851237 PMCID: PMC9959207 DOI: 10.3390/vaccines11020359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 01/30/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
Sphingomyelin is a major constituent of eukaryotic cell membranes, and if degraded by bacteria sphingomyelinases may contribute to the pathogenesis of infection. Among Leptospira spp., there are five sphingomyelinases exclusively expressed by pathogenic leptospires, in which Sph2 is expressed during natural infections, cytotoxic, and implicated in the leptospirosis hemorrhagic complications. Considering this and the lack of information about associations between Sph2 and leptospirosis severity, we use a combination of immunoinformatics approaches to identify its B-cell epitopes, evaluate their reactivity against samples from leptospirosis patients, and investigate the role of antibodies anti-Sph2 in protection against severe leptospirosis. Two B-cell epitopes, Sph2(176-191) and Sph2(446-459), were predicted in Sph2 from L. interrogans serovar Lai, presenting different levels of identity when compared with other pathogenic leptospires. These epitopes were recognized by about 40% of studied patients with a prevalence of IgG antibodies against both Sph2(176-191) and Sph2(446-459). Remarkably, just individuals with low reactivity to Sph2(176-191) presented clinical complications, while high responders had only mild symptoms. Therefore, we identified two B-cell linear epitopes, recognized by antibodies of patients with leptospirosis, that could be further explored in the development of multi-epitope vaccines against leptospirosis.
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Affiliation(s)
- Laura Sant’Anna Ataides
- Laboratório de Tecnologia Imunológica, Instituto de Tecnologia em Imunobiológicos, FIOCRUZ, Rio de Janeiro 21040-900, RJ, Brazil
| | - Fernanda de Moraes Maia
- Laboratório de Tecnologia Imunológica, Instituto de Tecnologia em Imunobiológicos, FIOCRUZ, Rio de Janeiro 21040-900, RJ, Brazil
| | - Fernando Paiva Conte
- Laboratório Piloto Eucariotos, Instituto de Tecnologia em Imunobiológicos, FIOCRUZ, Rio de Janeiro 21040-900, RJ, Brazil
| | - Lourdes Isaac
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil
| | - Angela Silva Barbosa
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo 05503-900, SP, Brazil
| | - Josué da Costa Lima-Junior
- Laboratório de Imunoparasitologia, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro 21040-900, RJ, Brazil
| | - Kátia Eliane Santos Avelar
- Laboratório de Referência Nacional para Leptospirose, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro 21040-900, RJ, Brazil
| | - Rodrigo Nunes Rodrigues-da-Silva
- Laboratório de Tecnologia Imunológica, Instituto de Tecnologia em Imunobiológicos, FIOCRUZ, Rio de Janeiro 21040-900, RJ, Brazil
- Correspondence: or ; Tel.: +55-21982054291
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Ashaiba A, Arun AB, Prasad KS, Tellis RC. Leptospiral sphingomyelinase Sph2 as a potential biomarker for diagnosis of leptospirosis. J Microbiol Methods 2022; 203:106621. [PMID: 36375539 DOI: 10.1016/j.mimet.2022.106621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022]
Abstract
Leptospirosis is an underestimated infectious tropical disease caused by the spirochetes belonging to the genus Leptospira. Leptospirosis is grossly underdiagnosed due to its myriad symptoms, varying from mild febrile illness to severe haemorrhage. Laboratory tests for leptospirosis is an extremely important and potent way for disease diagnosis, as the clinical manifestations are very similar to other febrile diseases. Currently available diagnostic techniques are time-consuming, require expertise and sophisticated instruments, and cannot identify the disease at an early phase of infection. Early diagnosis of leptospirosis is the need of the hour while considering the severe complications after the infection and the rate of mortality after misdiagnosis. Secretion of Leptospira-specific sphingomyelinases in leptospirosis patient's urine within a few days of the onset of infection is quite common and is a virulence factor present only in pathogenic Leptospira species. Herein, the structural and functional importance of leptospiral sphingomyelinase Sph2 in leptospirosis pathogenesis, as well as the potential of screening urinary Sph2 for diagnosis and the scope for developing a rapid and easily affordable point-of-care test for urinary leptospiral sphingomyelinase Sph2 as an alternative to current diagnostic methods are discussed.
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Affiliation(s)
- A Ashaiba
- Department of Microbiology, Yenepoya Medical College, Yenepoya (Deemed to be University), Deralakatte, Mangalore 575 018, India; Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore 575 018, India
| | - A B Arun
- Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore 575 018, India
| | - K Sudhakara Prasad
- Nano Materials Research Laboratory, Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore 575 018, India; Centre for Nutrition Studies, Yenepoya (Deemed to be University), Deralakatte, Mangalore 575 018, India.
| | - Rouchelle C Tellis
- Department of Microbiology, Yenepoya Medical College, Yenepoya (Deemed to be University), Deralakatte, Mangalore 575 018, India.
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Grassmann AA, Caimano MJ. Cultivation of Leptospira interrogans Within Rat Peritoneal Dialysis Membrane Chambers. Methods Mol Biol 2021; 2134:229-242. [PMID: 32632874 DOI: 10.1007/978-1-0716-0459-5_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
In order to sustain its zoonotic lifecycle, leptospires must adapt to growth within the host milieu. Signals encountered within the mammal also trigger regulatory programs required by Leptospira for the expression of virulence-related gene products. The complex transcriptional, antigenic, and physiological changes leptospires undergo within the mammal are collectively referred to as "host adaptation." In this chapter, we describe the procedures for the generation of host-adapted Leptospira spp. by cultivation within dialysis membrane chambers (DMCs) implanted in rat peritoneal cavities. In this model, Leptospira spp. diluted in EMJH medium are sequestered within sterile dialysis membrane tubing closed at both ends. The chamber then is surgically implanted within the peritoneal cavity of a rat and incubated for 7-10 days. During this period, leptospires are exposed to many, if not all, of the physiological and nutritional cues required for host adaptation while at the same time protected from clearance by host innate and adaptive immune defenses.
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Affiliation(s)
| | - Melissa J Caimano
- Departments of Medicine, Pediatrics, and Molecular Biology and Biophysics, University of Connecticut Health, Farmington, CT, USA.
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Paratsaphan S, Moonsom S, Reamtong O, Roytrakul S, Wuthiekanun V, Day NPJ, Sonthayanon P. Characterization of a Novel Peptide from Pathogenic Leptospira and Its Cytotoxic Effect. Pathogens 2020; 9:E906. [PMID: 33142957 PMCID: PMC7692646 DOI: 10.3390/pathogens9110906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/21/2020] [Accepted: 10/21/2020] [Indexed: 11/16/2022] Open
Abstract
Leptospirosis is a zoonotic infectious disease caused by pathogenic Leptospira species. Virulence proteins have been shown to be key determinants of the pathogenesis of pathogenic Leptospira. A specific peptide at a mass-to-charge ratio of 7000 Da was identified in Leptospira whole cells using matrix-assisted laser/desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. This peptide was specifically present in pathogenic Leptospira and in clinical isolates. We report here the characterization of this specific peptide using a proteomics approach. This peptide was significantly matched to a hypothetical conserved L. interrogans protein (LA2458) with a calculated molecular weight of 7140.136 Da containing a tellurite-resistance domain at its C terminus (TerB-C). The amino acid sequences revealed the presence of hydrophobic transmembrane portions and two linear B-cell epitopes. Despite its low abundance, this synthetic peptide demonstrated dose-dependent cytotoxicity toward African green monkey kidney (Vero) cells via the apoptosis pathway. The concentration of the peptide 100 µM induced about 50% of cell death after a 24 h exposure. This peptide could be useful for the diagnosis of leptospirosis and the study of pathogenesis.
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Affiliation(s)
- Saksakon Paratsaphan
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (S.P.); (O.R.)
| | - Saengduen Moonsom
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand;
| | - Onrapak Reamtong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (S.P.); (O.R.)
| | - Sittiruk Roytrakul
- Proteomics Research Laboratory, National Center for Genetic Engineering and Biotechnology, Pathumthani 12120, Thailand;
| | - Vanaporn Wuthiekanun
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (V.W.); (N.P.J.D.)
| | - Nicholas P. J. Day
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (V.W.); (N.P.J.D.)
- Centre for Tropical Medicine & Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Piengchan Sonthayanon
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (S.P.); (O.R.)
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (V.W.); (N.P.J.D.)
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cis-Acting Determinant Limiting Expression of Sphingomyelinase Gene sph2 in Leptospira interrogans, Identified with a gfp Reporter Plasmid. Appl Environ Microbiol 2018; 84:AEM.02068-18. [PMID: 30266732 DOI: 10.1128/aem.02068-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 09/25/2018] [Indexed: 12/29/2022] Open
Abstract
Many strains of the spirochete Leptospira interrogans serovar Pomona express the osmotically inducible sphingomyelinase gene sph2 at much higher levels than strains from other serovars. We developed a new green fluorescent protein (GFP) reporter plasmid to examine sph2 gene expression determinants. The vector enables the fusion of the test promoter to the ribosome-binding site and coding region of gfp We fused the sph2 promoters from the L. interrogans serovar Lai strain 56601 and from the L. interrogans serovar Pomona strain LC82-25 to gfp to examine the molecular determinants of differential sph2 expression between the two strains. Similar to what was observed with the native sph2 genes, the introduction of the plasmids into the Lai 56601 strain resulted in near background levels of gfp expression from the Lai sph2 promoter, while the expression from the Pomona sph2 promoter was high. The expression of both fusions increased at physiologic levels of osmolarity achieved by adding sodium chloride to the culture medium. We examined the role of a 17-bp upstream element found in all L. interrogans strains expressing low basal levels of sph2 and missing from Pomona strains that express sph2 at high levels. When the 17-bp sequence present upstream of the Lai sph2 promoter was deleted or scrambled, the fusion expression increased substantially. Conversely, the insertion of the 17-bp sequence upstream of the Pomona sph2 promoter diminished fusion expression. In contrast, the removal of an insertion sequence-like element that is found only in the Pomona sph2 upstream sequence had no effect on the expression from the Pomona sph2 fusion in the Lai strain. These findings demonstrate the utility of the gfp reporter plasmid in analyzing gene expression in L. interrogans IMPORTANCE Genetic tools are needed to examine gene expression in the pathogen Leptospira interrogans We developed a reporter plasmid that replicates in L. interrogans with green fluorescent protein (GFP) as the readout of promoter activity. We demonstrated an application of the new reporter plasmid by identifying an upstream element responsible for the poor basal expression of the sph2 sphingomyelinase gene in an L. interrogans serovar Lai strain. This new tool is useful for the discovery of the molecular determinants of L. interrogans gene expression.
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Wood PL, Steinman M, Erol E, Carter C, Christmann U, Verma A. Lipidomic analysis of immune activation in equine leptospirosis and Leptospira-vaccinated horses. PLoS One 2018; 13:e0193424. [PMID: 29474474 PMCID: PMC5825116 DOI: 10.1371/journal.pone.0193424] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 02/09/2018] [Indexed: 12/16/2022] Open
Abstract
Currently available diagnostic assays for leptospirosis cannot differentiate vaccine from infection serum antibody. Several leptospiral proteins that are upregulated during infection have been described, but their utility as a diagnostic marker is still unclear. In this study, we undertook a lipidomics approach to determine if there are any differences in the serum lipid profiles of horses naturally infected with pathogenic Leptospira spp. and horses vaccinated against a commercially available bacterin. Utilizing a high-resolution mass spectrometry serum lipidomics analytical platform, we demonstrate that cyclic phosphatidic acids, diacylglycerols, and hydroperoxide oxidation products of choline plasmalogens are elevated in the serum of naturally infected as well as vaccinated horses. Other lipids of interest were triacylglycerols that were only elevated in the serum of infected horses and sphingomyelins that were increased only in the serum of vaccinated horses. This is the first report looking at the equine serum lipidome during leptospiral infection and vaccination.
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Affiliation(s)
- Paul L. Wood
- Metabolomics Unit, College of Veterinary Medicine, Lincoln Memorial University, Harrogate, Tennessee, United States of America
- * E-mail: (PLW); (AV)
| | - Margaret Steinman
- Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, Kentucky, United States of America
| | - Erdal Erol
- Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, Kentucky, United States of America
| | - Craig Carter
- Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, Kentucky, United States of America
| | - Undine Christmann
- Center for Infectious, Zoonotic and Vector-borne Diseases, College of Veterinary Medicine, Lincoln Memorial University, Harrogate, Tennessee, United States of America
| | - Ashutosh Verma
- Center for Infectious, Zoonotic and Vector-borne Diseases, College of Veterinary Medicine, Lincoln Memorial University, Harrogate, Tennessee, United States of America
- * E-mail: (PLW); (AV)
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Fraser T, Brown PD. Temperature and Oxidative Stress as Triggers for Virulence Gene Expression in Pathogenic Leptospira spp. Front Microbiol 2017; 8:783. [PMID: 28536558 PMCID: PMC5423269 DOI: 10.3389/fmicb.2017.00783] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 04/18/2017] [Indexed: 01/21/2023] Open
Abstract
Leptospirosis is a zooanthroponosis aetiologically caused by pathogenic bacteria belonging to the genus, Leptospira. Environmental signals such as increases in temperatures or oxidative stress can trigger response regulatory modes of virulence genes during infection. This study sought to determine the effect of temperature and oxidative stress on virulence associated genes in highly passaged Leptospira borgpeterseneii Jules and L. interrogans Portlandvere. Bacteria were grown in EMJH at 30°C, 37°C, or at 30°C before being transferred to 37°C. A total of 14 virulence-associated genes (fliY, invA, lenA, ligB, lipL32, lipL36, lipL41, lipL45, loa22, lsa21, mce, ompL1, sph2, and tlyC) were assessed using endpoint PCR. Transcriptional analyses of lenA, lipL32, lipL41, loa22, sph2 were assessed by quantitative real-time RT-PCR at the temperature conditions. To assess oxidative stress, bacteria were exposed to H2O2 for 30 and 60 min with or without the temperature stress. All genes except ligB (for Portlandvere) and ligB and mce (for Jules) were detectable in the strains. Quantitatively, temperature stress resulted in significant changes in gene expression within species or between species. Temperature changes were more influential in gene expression for Jules, particularly at 30°C and upshift conditions; at 37°C, expression levels were higher for Portlandvere. However, compared to Jules, where temperature was influential in two of five genes, temperature was an essential element in four of five genes in Portlandvere exposed to oxidative stress. At both low and high oxidative stress levels, the interplay between genetic predisposition (larger genome size) and temperature was biased towards Portlandvere particularly at 30°C and upshift conditions. While it is clear that expression of many virulence genes in highly passaged strains of Leptospira are attenuated or lost, genetic predisposition, changes in growth temperature and/or oxidative intensity and/or duration were factors which acted in isolation or together with other regulatory cues to contribute to the variable gene expression observed in this study. Overall, differential gene expression in serovar Portlandvere was more responsive to temperature and oxidative stress.
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Affiliation(s)
- Tricia Fraser
- Department of Basic Medical Sciences, Biochemistry Section, University of the West IndiesMona, Jamaica.,Veterinary Services Division, Ministry of AgricultureHope Gardens, Jamaica
| | - Paul D Brown
- Department of Basic Medical Sciences, Biochemistry Section, University of the West IndiesMona, Jamaica
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Abstract
Lipoproteins are lipid-modified proteins that dominate the spirochetal proteome. While found in all bacteria, spirochetal lipoproteins have unique features and play critical roles in spirochete biology. For this reason, considerable effort has been devoted to determining how the lipoproteome is generated. Essential features of the structural elements of lipoproteins are now understood with greater clarity, enabling greater confidence in identification of lipoproteins from genomic sequences. The journey from the ribosome to the outer membrane, and in some cases, to the cellular surface has been defined, including secretion, lipidation, sorting, and export across the outer membrane. Given their abundance and importance, it is not surprising that spirochetes have developed a number of strategies for regulating the spatiotemporal expression of lipoproteins. In some cases, lipoprotein expression is tied to various environmental cues, while in other cases, it is linked to growth rate. This regulation enables spirochetes to express certain lipoproteins at high levels in one phase of the spirochete lifecycle, while dramatically downregulating the same lipoproteins in other phases. The mammalian host has developed specialized mechanisms for recognizing lipoproteins and triggering an immune response. Evasion of that immune response is essential for spirochete persistence. For this reason, spirochetes have developed mechanisms for altering lipoproteins. Lipoproteins recognized by antibodies formed during infection are key serodiagnostic antigens. In addition, lipoprotein vaccines have been developed for generating an immune response to control or prevent a spirochete infection. This chapter summarizes our current understanding of lipoproteins in interactions of spirochetes with their hosts.
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Velineni S, Timoney JF. Preliminary evaluation of a dual antigen ELISA to distinguish vaccinated from Leptospira infected horses. Vet Rec 2016; 179:574. [PMID: 27650465 DOI: 10.1136/vr.103686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2016] [Indexed: 11/04/2022]
Abstract
Immunogenic proteins of Leptospira interrogans serovar Pomona type kennewicki (Lk) including Sph1, LigA, Hsp15 and LipL45 (Qlp42) are up-regulated in infected horses but are undetectable or expressed in trace amounts on cultured organisms. In contrast, LipL32 is abundant on cultured Lk and elicits infection antibody responses. The aim of this study was to develop an ELISA based on LipL32 or Lk sonicate and host-induced proteins to differentiate vaccine from infection serum antibody. IgG specific for recombinant Sph1, LigA, Lk90 (LigA; 379-1225 a.a), Hsp15, LipL45 and LipL32 of Lk were assayed in sera of horses infected naturally with Lk and before and after immunisation with serovar Pomona bacterin. Infection but not vaccine sera reacted strongly with Sph1, LigA and Lk90. LipL45 and Hsp15 reacted moderately with infection sera and weakly with vaccine sera. Lk sonicate and LipL32 reacted strongly with both infection and vaccine sera. As expected, culture-based vaccine failed to stimulate antibody to host-induced proteins. Therefore a dual antigen ELISA based on Lk sonicate or LipL32 combined with host-induced Sph1 and Lk90 will be valuable in differentiating infection from vaccine responses.
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Affiliation(s)
- S Velineni
- Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky 40546, USA
| | - J F Timoney
- Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky 40546, USA
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Velineni S, Timoney JF, Artiushin SC, Donahue JM, Steinman M. Multiple specificities of immunoglobulin M in equine fetuses infected with Leptospira interrogans indicate a competent immune response. Equine Vet J 2015; 48:704-709. [PMID: 26671764 DOI: 10.1111/evj.12527] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 10/14/2015] [Indexed: 11/30/2022]
Abstract
REASONS FOR PERFORMING STUDY Foals of mares infected with Leptospira interrogans serovar Pomona type kennewicki (Lk) may be aborted/stillborn or delivered as healthy foals. Is fetal survival explained in part by the immune response of the fetus to Leptospira antigens? OBJECTIVES To describe an outbreak of Leptospira abortion in which infected mares delivered dead/sick or normal foals and determine specificities of antibody in a collection of 54 fetuses from similar outbreaks. STUDY DESIGN Outbreak investigation in combination with a case-control study of a larger set of samples from aborted fetuses. METHODS Serology and polymerase chain reaction (PCR) on urine and amniotic fluids were used to diagnose infection during an outbreak of Leptospira abortion. Specificities of immunoglobulin (Ig)M, IgGa and IgGb for recombinant proteins of Lk in archived fluids of fetuses from similar outbreaks were compared by ELISA with those of fluids of fetuses not infected with Leptospira spp. RESULTS Five fetuses of 11 infected mares in an outbreak survived in utero in the presence of persistent placental infection and were healthy at foaling. Fetuses of 6 mares in the outbreak were aborted or died soon after birth. Significantly greater (P<0.05) IgM reactivity with all recombinant proteins and with Lk sonicate was observed in 54 archived fluids from Leptospira infected fetuses than in fluids of 30 of non-Leptospira infected fetuses. Low levels of IgGa and IgGb specific for LipL32 and Lk sonicate and traces of LigA and Hsp15 specific IgGa were detected in a minority of archived fluids from Leptospira infected fetuses. CONCLUSION Although mainly mediated by IgM, a high level of immune competence in aborted fetuses was evidenced by the multiplicity of Leptospira proteins targeted. This is likely to contribute to survival of foals in mares with evidence of placental infection at foaling as detailed in a typical outbreak.
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Affiliation(s)
- S Velineni
- Gluck Equine Research Center, University of Kentucky, Lexington, USA
| | - J F Timoney
- Gluck Equine Research Center, University of Kentucky, Lexington, USA.
| | - S C Artiushin
- Gluck Equine Research Center, University of Kentucky, Lexington, USA
| | - J M Donahue
- University of Kentucky Veterinary Diagnostic Laboratory, Lexington, USA
| | - M Steinman
- University of Kentucky Veterinary Diagnostic Laboratory, Lexington, USA
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Narayanavari SA, Lourdault K, Sritharan M, Haake DA, Matsunaga J. Role of sph2 Gene Regulation in Hemolytic and Sphingomyelinase Activities Produced by Leptospira interrogans. PLoS Negl Trop Dis 2015; 9:e0003952. [PMID: 26274394 PMCID: PMC4537108 DOI: 10.1371/journal.pntd.0003952] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 07/06/2015] [Indexed: 12/19/2022] Open
Abstract
Pathogenic members of the genus Leptospira are the causative agents of leptospirosis, a neglected disease of public and veterinary health concern. Leptospirosis is a systemic disease that in its severest forms leads to renal insufficiency, hepatic dysfunction, and pulmonary failure. Many strains of Leptospira produce hemolytic and sphingomyelinase activities, and a number of candidate leptospiral hemolysins have been identified based on sequence similarity to well-characterized bacterial hemolysins. Five of the putative hemolysins are sphingomyelinase paralogs. Although recombinant forms of the sphingomyelinase Sph2 and other hemolysins lyse erythrocytes, none have been demonstrated to contribute to the hemolytic activity secreted by leptospiral cells. In this study, we examined the regulation of sph2 and its relationship to hemolytic and sphingomyelinase activities produced by several L. interrogans strains cultivated under the osmotic conditions found in the mammalian host. The sph2 gene was poorly expressed when the Fiocruz L1-130 (serovar Copenhageni), 56601 (sv. Lai), and L495 (sv. Manilae) strains were cultivated in the standard culture medium EMJH. Raising EMJH osmolarity to physiological levels with sodium chloride enhanced Sph2 production in all three strains. In addition, the Pomona subtype kennewicki strain LC82-25 produced substantially greater amounts of Sph2 during standard EMJH growth than the other strains, and sph2 expression increased further by addition of salt. When 10% rat serum was present in EMJH along with the sodium chloride supplement, Sph2 production increased further in all strains. Osmotic regulation and differences in basal Sph2 production in the Manilae L495 and Pomona strains correlated with the levels of secreted hemolysin and sphingomyelinase activities. Finally, a transposon insertion in sph2 dramatically reduced hemolytic and sphingomyelinase activities during incubation of L. interrogans at physiologic osmolarity. Complementation of the mutation with the sph2 gene partially restored production of hemolytic and sphingomyelinase activities. These results indicate that the sph2 gene product contributes to the hemolytic and sphingomyelinase activities secreted by L. interrogans and most likely dominates those functions under the culture condition tested. The spirochete Leptospira causes leptospirosis, a potentially deadly disease of humans and animals. Candidate factors that promote infection include hemolysins encoded by several leptospiral genes. Hemolysins rupture red blood cells in vitro. Some hemolysins are sphingomyelinases, which target sphingomyelin in the host cell membrane. Hemolysins have the potential to disrupt organ function during infection. It is not known which hemolysins and sphingomyelinases are responsible for the hemolytic and sphingomyelinase activities secreted by L. interrogans. We found that the production of hemolytic activity is regulated and is tied to expression of sph2, which encodes a hemolysin with sphingomyelinase, cytotoxic, and fibronectin-binding activities. Hemolytic and sphingomyelinase activities and sph2 expression were higher when the osmolarity of the culture medium was raised to the level found in the mammalian host. Similarly, sph2 expression was substantially higher in an L. interrogans strain that secreted large amounts of hemolytic and sphingomyelinase activities than in a strain that generated negligible amounts. Most importantly, disruption of the sph2 gene eliminated hemolysin production and yielded substantially less sphingomyelinase than the wild-type strain. Our findings indicate that sph2 is a major contributor to the hemolytic and sphingomyelinase activities secreted by L. interrogans and that the hemolytic and sphingomyelinase activities measured in standard L. interrogans cultures may underestimate the levels produced during infection.
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Affiliation(s)
| | - Kristel Lourdault
- Research Service, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America; Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
| | - Manjula Sritharan
- Department of Animal Biology, University of Hyderabad, Hyderabad, India
| | - David A Haake
- Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, California, United States of America; Department of Urology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, California, United States of America; Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America; Division of Infectious Diseases, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
| | - James Matsunaga
- Research Service, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America; Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
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Abstract
The mechanisms of disease pathogenesis in leptospirosis are poorly defined. Recent developments in the application of genetic tools in the study of Leptospira have advanced our understanding by allowing the assessment of mutants in animal models. As a result, a small number of essential virulence factors have been identified, though most do not have a clearly defined function. Significant advances have also been made in the in vitro characterization of leptospiral interaction with host structures, including extracellular matrix proteins (such as laminin, elastin, fibronectin, collagens), proteins related to hemostasis (fibrinogen, plasmin), and soluble mediators of complement resistance (factor H, C4b-binding protein), although none of these in vitro findings has been translated to the host animal. Binding to host structures may permit colonization of the host, prevention of blood clotting may contribute to hemorrhage, while interaction with complement resistance mediators may contribute to survival in serum. While not a classical intracellular pathogen, the interaction of leptospires and phagocytic cells appears complex, with bacteria surviving uptake and promoting apoptosis; mutants relating to these processes (such as cell invasion and oxidative stress resistance) are attenuated in vivo. Another feature of leptospiral biology is the high degree of functional redundancy and the surprising lack of attenuation of mutants in what appear to be certain virulence factors, such as LipL32 and LigB. While many advances have been made, there remains a lack of understanding of how Leptospira causes tissue pathology. It is likely that leptospires have many novel pathogenesis mechanisms that are yet to be identified.
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A model system for studying the transcriptomic and physiological changes associated with mammalian host-adaptation by Leptospira interrogans serovar Copenhageni. PLoS Pathog 2014; 10:e1004004. [PMID: 24626166 PMCID: PMC3953431 DOI: 10.1371/journal.ppat.1004004] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 02/01/2014] [Indexed: 12/23/2022] Open
Abstract
Leptospirosis, an emerging zoonotic disease with worldwide distribution, is caused by spirochetes belonging to the genus Leptospira. More than 500,000 cases of severe leptospirosis are reported annually, with >10% of these being fatal. Leptospires can survive for weeks in suitably moist conditions before encountering a new host. Reservoir hosts, typically rodents, exhibit little to no signs of disease but shed large numbers of organisms in their urine. Transmission occurs when mucosal surfaces or abraded skin come into contact with infected urine or urine-contaminated water or soil. In humans, leptospires can cause a variety of clinical manifestations, ranging from asymptomatic or mild fever to severe icteric (Weil's) disease and pulmonary haemorrhage. Currently, little is known about how Leptospira persist within a reservoir host. Prior in vitro studies have suggested that leptospires alter their transcriptomic and proteomic profiles in response to environmental signals encountered during mammalian infection. However, no study has examined gene expression by leptospires within a mammalian host-adapted state. To obtain a more faithful representation of how leptospires respond to host-derived signals, we used RNA-Seq to compare the transcriptome of L. interrogans cultivated within dialysis membrane chambers (DMCs) implanted into the peritoneal cavities of rats with that of organisms grown in vitro. In addition to determining the relative expression levels of “core” housekeeping genes under both growth conditions, we identified 166 genes that are differentially-expressed by L. interrogans in vivo. Our analyses highlight physiological aspects of host adaptation by leptospires relating to heme uptake and utilization. We also identified 11 novel non-coding transcripts that are candidate small regulatory RNAs. The DMC model provides a facile system for studying the transcriptional and antigenic changes associated with mammalian host-adaption, selection of targets for mutagenesis, and the identification of previously unrecognized virulence determinants. Leptospirosis, a global disease caused by the unusual bacterium Leptospira, is transmitted from animals to humans. Pathogenic species of Leptospira are excreted in urine from infected animals and can continue to survive in suitable environments before coming into contact with a new reservoir or accidental host. Leptospires have an inherent ability to survive a wide range of conditions encountered in nature during transmission and within mammals. However, we know very little about the regulatory pathways and gene products that promote mammalian host adaptation and enable leptospires to establish infection. In this study, we used a novel system whereby leptospires are cultivated in dialysis membrane chambers implanted into the peritoneal cavities of rats to compare the gene expression profiles of mammalian host-adapted and in vitro-cultivated organisms. In addition to providing a facile system for studying the transcriptional and physiologic changes leptospires undergo during mammalian infection, our data provide a rational basis for selecting new targets for mutagenesis.
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Identification of Sphingomyelinase on the Surface of Chlamydia pneumoniae: Possible Role in the Entry into Its Host Cells. Interdiscip Perspect Infect Dis 2014; 2014:412827. [PMID: 24757444 PMCID: PMC3976853 DOI: 10.1155/2014/412827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/19/2014] [Indexed: 11/18/2022] Open
Abstract
We have recently suggested a novel mechanism, autoendocytosis, for the entry of certain microbes into their hosts, with a key role played by the sphingomyelinase-catalyzed topical conversion of sphingomyelin to ceramide, the differences in the biophysical properties of these two lipids providing the driving force. The only requirement for such microbes to utilize this mechanism is that they should have a catalytically active SMase on their outer surface while the target cells should expose sphingomyelin in the external leaflet of their plasma membrane. In pursuit of possible microbial candidates, which could utilize this putative mechanism, we conducted a sequence similarity search for SMase. Because of the intriguing cellular and biochemical characteristics of the poorly understood entry of Chlamydia into its host cells these microbes were of particular interest. SMase activity was measured in vitro from isolated C. pneumoniae elementary bodies (EB) and in the lysate from E. coli cells transfected with a plasmid expressing CPn0300 protein having sequence similarity to SMase. Finally, pretreatment of host cells with exogenous SMase resulting in loss plasma membrane sphingomyelin attenuated attachment of EB.
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Verma AK, Kumar A, Dhama K, Deb R, Rahal A, Chakraborty S. Leptospirosis-persistence of a dilemma: an overview with particular emphasis on trends and recent advances in vaccines and vaccination strategies. Pak J Biol Sci 2012; 15:954-963. [PMID: 24199473 DOI: 10.3923/pjbs.2012.954.963] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Leptospirosis, caused by pathogenic spirochetes of the genus Leptospira, affects both humans and animals and is among the most common but neglected direct zoonotic disease in the world, particularly in untreated or undiagnosed animals as well as humans. Now, it has been considered as a re-emerging disease causing global health problem due to its increasing incidences in developing as well as developed nations. It is a multisystemic disease leading to death. Diagnostic tests of importance are Latex Agglutination Test (LAT), lateral flow and immunoglobulin M (IgM) based ELISA, PCR based assays, Multiple-microscopic Agglutination Test (MAT), Loop-mediated Isothermal Amplification (LAMP) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Molecular tools like PCR-RFLP, real-time PCR, multiplex PCR, qPCR and immunocapture PCR have all been found useful for rapid and confirmatory detection and differentiation of pathogenic and non-pathogenic leptospires. Inactivated/killed and attenuated vaccines are always attempted, since the beginning of vaccine and vaccination story, against all emerging pathogens with mixed success stories. The advanced tools and techniques like recombinant DNA technology, reverse genetics, DNA vaccination, molecular genetics and proteomics approaches are being explored for search of novel antigens, proteins and genes as potential candidates to discover safer, efficient and better vaccines for leptospirosis. The present review highlights the leptospirosis, susceptible population, disease transmission and epidemiology, treatment, trends and advances in diagnosis, vaccines and vaccination strategies in humans and animals with a view to combat this organism having public health significance.
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Affiliation(s)
- Amit Kumar Verma
- Department of Veterinary Epidemiology and Preventive Medicine, Uttar Pradesh Pandit Deen Dayal Upadhayay Pashu Chikitsa Vigyan Vishvidhyalaya Ewam Go-Anusandhan Sansthan (DUVASU), Mathura (U.P.), India
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Detection and characterization of Leptospira spp. isolated from aborted bovine clinical samples. ACTA VET BRNO 2012. [DOI: 10.2754/avb201281010021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Leptospira is recognized as an important public health problem worldwide, especially in tropical countries, and is a common cause of abortion in dairy and beef herds. The aim of the present study was to detect and characterize Leptospira as the causative agent of abortion in cattle using a PCR-RFLP in Chaharmahal va Bakhtiari and Isfahan provinces, Iran. A total of 220 bovine aborted foetuses and 120 vaginal discharges from an aborted calf were collected from 64 commercial dairy herds. After isolation of 60 Leptospira spp. from samples, RFLP analysis was carried out with HindIII and HaeIII restriction enzymes in reference strains and isolated for characterization. In a total of 340 specimens, 46 (20.9%) and 14 (11.66%) were identified positive for Leptospira spp. from aborted bovine foetuses and vaginal discharges, respectively. The present results also suggest that L. interrogans serovar hardjo has the highest prevalence in the region under study and L. hardjo is a major pathogen causing bovine abortion in Chaharmahal va Bakhtiari and Isfahan provinces of Iran.
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Narayanavari SA, Kishore NM, Sritharan M. Structural analysis of the Leptospiral sphingomyelinases: in silico and experimental evaluation of Sph2 as an Mg-dependent sphingomyelinase. J Mol Microbiol Biotechnol 2012; 22:24-34. [PMID: 22441407 DOI: 10.1159/000337013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Leptospiral sphingomyelinases are candidate virulence factors present only in pathogenic Leptospira spp. Leptospira interrogans serovar Lai encodes Sph1, Sph2, Sph3, Sph4 and SphH. Except for Sph4, they all possess the exo-endo-phosphatase domain that groups them under the DNase I superfamily. METHODS, RESULTS AND CONCLUSIONS Modeling of exo-endo-phosphatase domains reveals high-level structural similarity of Sph2 with the crystal structure of SmcL and BC SMase sphingomyelinases from Listeria ivanovii and Bacillus cereus, respectively. A β-hairpin loop, essential for host cell membrane interaction, is absent in leptospiral sphingomyelinases. Instead, several aromatic amino acids were oriented outward from the surface of these molecules and formed clusters of hydrophobic regions that possibly enables the anchoring of these molecules into the host cell membrane, as demonstrated in Sph2 and Sph3. Sph2 is unique and possesses the Mg(++)-binding Glu53 residue in the metal-binding site and two His residues (His151 and His286) in the catalytic site. We demonstrate experimentally the Mg(++)-dependent hemolysis of erythrocytes by rSph2 and its ability to cleave sphingomyelin to ceramide. Anti-Sph2 antibodies neutralized the hemolytic activity of Sph2. In conclusion, we provide evidence showing that Sph2 is a Mg(++)-dependent hemolysin with both sphingomyelinase and hemolytic activities.
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Affiliation(s)
- Suneel A Narayanavari
- Department of Animal Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, India
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Narayanavari SA, Sritharan M, Haake DA, Matsunaga J. Multiple leptospiral sphingomyelinases (or are there?). MICROBIOLOGY-SGM 2012; 158:1137-1146. [PMID: 22422753 DOI: 10.1099/mic.0.057737-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Culture supernatants of leptospiral pathogens have long been known to haemolyse erythrocytes. This property is due, at least in part, to sphingomyelinase activity. Indeed, genome sequencing reveals that pathogenic Leptospira species are richly endowed with sphingomyelinase homologues: five genes have been annotated to encode sphingomyelinases in Leptospira interrogans. Such redundancy suggests that this class of genes is likely to benefit leptospiral pathogens in their interactions with the mammalian host. Surprisingly, sequence comparison with bacterial sphingomyelinases for which the crystal structures are known reveals that only one of the leptospiral homologues has the active site amino acid residues required for enzymic activity. Based on studies of other bacterial toxins, we propose that leptospiral sphingomyelinase homologues, irrespective of their catalytic activity, may possess additional molecular functions that benefit the spirochaete. Potential secretion pathways and roles in pathogenesis are discussed, including nutrient acquisition, dissemination, haemorrhage and immune evasion. Although leptospiral sphingomyelinase-like proteins are best known for their cytolytic properties, we believe that a better understanding of their biological role requires the examination of their sublytic properties as well.
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Affiliation(s)
| | - Manjula Sritharan
- Department of Animal Sciences, University of Hyderabad, Hyderabad, India
| | - David A Haake
- Department of Medicine, University of California at Los Angeles, Los Angeles, CA, USA.,Department of Urology, University of California at Los Angeles, Los Angeles, CA, USA.,Division of Infectious Diseases, VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA.,Department of Microbiology, Immunology, and Molecular Genetics, University of California at Los Angeles, Los Angeles, CA, USA
| | - James Matsunaga
- Research Service, VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA.,Department of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
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Eshghi A, Pinne M, Haake DA, Zuerner RL, Frank A, Cameron CE. Methylation and in vivo expression of the surface-exposed Leptospira interrogans outer-membrane protein OmpL32. MICROBIOLOGY-SGM 2011; 158:622-635. [PMID: 22174381 DOI: 10.1099/mic.0.054767-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recent studies have revealed that bacterial protein methylation is a widespread post-translational modification that is required for virulence in selected pathogenic bacteria. In particular, altered methylation of outer-membrane proteins has been shown to modulate the effectiveness of the host immune response. In this study, 2D gel electrophoresis combined with MALDI-TOF MS identified a Leptospira interrogans serovar Copenhageni strain Fiocruz L1-130 protein, corresponding to ORF LIC11848, which undergoes extensive and differential methylation of glutamic acid residues. Immunofluorescence microscopy implicated LIC11848 as a surface-exposed outer-membrane protein, prompting the designation OmpL32. Indirect immunofluorescence microscopy of golden Syrian hamster liver and kidney sections revealed expression of OmpL32 during colonization of these organs. Identification of methylated surface-exposed outer-membrane proteins, such as OmpL32, provides a foundation for delineating the role of this post-translational modification in leptospiral virulence.
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Affiliation(s)
- Azad Eshghi
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Marija Pinne
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA.,Research Service, 151, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - David A Haake
- Division of Infectious Diseases, 111F, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA.,Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA
| | - Richard L Zuerner
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center (NADC), Agricultural Research Service (ARS), United States Department of Agriculture (USDA), Ames, IA, USA
| | - Ami Frank
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center (NADC), Agricultural Research Service (ARS), United States Department of Agriculture (USDA), Ames, IA, USA
| | - Caroline E Cameron
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
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21
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A unique genotype of Leptospira interrogans serovar Pomona type kennewicki is associated with equine abortion. Vet Microbiol 2011; 150:349-53. [DOI: 10.1016/j.vetmic.2011.02.049] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 02/16/2011] [Accepted: 02/21/2011] [Indexed: 11/24/2022]
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Cerqueira GM, Souza NM, Araújo ER, Barros AT, Morais ZM, Vasconcellos SA, Nascimento ALTO. Development of transcriptional fusions to assess Leptospira interrogans promoter activity. PLoS One 2011; 6:e17409. [PMID: 21445252 PMCID: PMC3060810 DOI: 10.1371/journal.pone.0017409] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 01/31/2011] [Indexed: 11/29/2022] Open
Abstract
Background Leptospirosis is a zoonotic infectious disease that affects both humans and animals. The existing genetic tools for Leptospira spp. have improved our understanding of the biology of this spirochete as well as the interaction of pathogenic leptospires with the mammalian host. However, new tools are necessary to provide novel and useful information to the field. Methodology and Principal Findings A series of promoter-probe vectors carrying a reporter gene encoding green fluorescent protein (GFP) were constructed for use in L. biflexa. They were tested by constructing transcriptional fusions between the lipL41, Leptospiral Immunoglobulin-like A (ligA) and Sphingomielynase 2 (sph2) promoters from L. interrogans and the reporter gene. ligA and sph2 promoters were the most active, in comparison to the lipL41 promoter and the non-induced controls. The results obtained are in agreement with LigA expression from the L. interrogans Fiocruz L1-130 strain. Conclusions The novel vectors facilitated the in vitro evaluation of L. interrogans promoter activity under defined growth conditions which simulate the mammalian host environment. The fluorescence and rt-PCR data obtained closely reflected transcriptional regulation of the promoters, thus demonstrating the suitability of these vectors for assessing promoter activity in L. biflexa.
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Evangelista KV, Coburn J. Leptospira as an emerging pathogen: a review of its biology, pathogenesis and host immune responses. Future Microbiol 2011; 5:1413-25. [PMID: 20860485 DOI: 10.2217/fmb.10.102] [Citation(s) in RCA: 196] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Leptospirosis, the most widespread zoonosis in the world, is an emerging public health problem, particularly in large urban centers of developing countries. Several pathogenic species of the genus Leptospira can cause a wide range of clinical manifestations, from a mild, flu-like illness to a severe disease form characterized by multiorgan system complications leading to death. However, the mechanisms of pathogenesis of Leptospira are largely unknown. This article will address the animal models of acute and chronic leptospire infections, and the recent developments in the genetic manipulation of the bacteria, which facilitate the identification of virulence factors involved in pathogenesis and the assessment of their potential values in the control and prevention of leptospirosis.
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Affiliation(s)
- Karen V Evangelista
- Department of Microbiology & Molecular Genetics, Medical College of Wisconsin, Milwaukee, USA
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Xue F, Dong H, Wu J, Wu Z, Hu W, Sun A, Troxell B, Yang XF, Yan J. Transcriptional responses of Leptospira interrogans to host innate immunity: significant changes in metabolism, oxygen tolerance, and outer membrane. PLoS Negl Trop Dis 2010; 4:e857. [PMID: 21049008 PMCID: PMC2964297 DOI: 10.1371/journal.pntd.0000857] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 09/27/2010] [Indexed: 12/31/2022] Open
Abstract
Background Leptospira interrogans is the major causative agent of leptospirosis. Phagocytosis plays important roles in the innate immune responses to L. interrogans infection, and L. interrogans can evade the killing of phagocytes. However, little is known about the adaptation of L. interrogans during this process. Methodology/Principal Findings To better understand the interaction of pathogenic Leptospira and innate immunity, we employed microarray and comparative genomics analyzing the responses of L. interrogans to macrophage-derived cells. During this process, L. interrogans altered expressions of many genes involved in carbohydrate and lipid metabolism, energy production, signal transduction, transcription and translation, oxygen tolerance, and outer membrane proteins. Among them, the catalase gene expression was significantly up-regulated, suggesting it may contribute to resisting the oxidative pressure of the macrophages. The expressions of several major outer membrane protein (OMP) genes (e.g., ompL1, lipL32, lipL41, lipL48 and ompL47) were dramatically down-regulated (10–50 folds), consistent with previous observations that the major OMPs are differentially regulated in vivo. The persistent down-regulations of these major OMPs were validated by immunoblotting. Furthermore, to gain initial insight into the gene regulation mechanisms in L. interrogans, we re-defined the transcription factors (TFs) in the genome and identified the major OmpR TF gene (LB333) that is concurrently regulated with the major OMP genes, suggesting a potential role of LB333 in OMPs regulation. Conclusions/Significance This is the first report on global responses of pathogenic Leptospira to innate immunity, which revealed that the down-regulation of the major OMPs may be an immune evasion strategy of L. interrogans, and a putative TF may be involved in governing these down-regulations. Alterations of the leptospiral OMPs up interaction with host antigen-presenting cells (APCs) provide critical information for selection of vaccine candidates. In addition, genome-wide annotation and comparative analysis of TFs set a foundation for further studying regulatory networks in Leptospira spp. Leptospirosis is an important tropical disease around the world, particularly in humid tropical and subtropical countries. As a major pathogen of this disease, Leptospira interrogans can be shed from the urine of reservoir hosts, survive in soil and water, and infect humans through broken skin or mucous membranes. Recently, host adaptability and immune evasion of L. interrogans to host innate immunity was partially elucidated in infection or animal models. A better understanding of the molecular mechanisms of L. interrogans in response to host innate immunity is required to learn the nature of early leptospirosis. This study focused on the transcriptome of L. interrogans during host immune cells interaction. Significant changes in energy metabolism, oxygen tolerance and outer membrane protein profile were identified as potential immune evasion strategies by pathogenic Leptospira during the early stage of infection. The major outer membrane proteins (OMPs) of L. interrogans may be regulated by the major OmpR specific transcription factor (LB333). These results provide a foundation for further studying the pathogenesis of leptospirosis, as well as identifying gene regulatory networks in Leptospira spp.
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Affiliation(s)
- Feng Xue
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China
- Department of Medical Microbiology and Parasitology, Medical College, Zhejiang University School of Medicine, Hangzhou, China
| | - Haiyan Dong
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China
- Department of Medical Microbiology and Parasitology, Medical College, Zhejiang University School of Medicine, Hangzhou, China
| | - Jinyu Wu
- Zhejiang Provincial Key Laboratory of Medical Genetics, Institute of Biomedical Informatics, Wenzhou Medical College, Wenzhou, China
| | - Zuowei Wu
- Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Weilin Hu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China
- Department of Medical Microbiology and Parasitology, Medical College, Zhejiang University School of Medicine, Hangzhou, China
| | - Aihua Sun
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China
- Department of Medical Microbiology and Parasitology, Medical College, Zhejiang University School of Medicine, Hangzhou, China
| | - Bryan Troxell
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - X. Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Jie Yan
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China
- Department of Medical Microbiology and Parasitology, Medical College, Zhejiang University School of Medicine, Hangzhou, China
- * E-mail:
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Verma A, Brissette CA, Bowman AA, Shah ST, Zipfel PF, Stevenson B. Leptospiral endostatin-like protein A is a bacterial cell surface receptor for human plasminogen. Infect Immun 2010; 78:2053-9. [PMID: 20160016 PMCID: PMC2863546 DOI: 10.1128/iai.01282-09] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2009] [Revised: 12/05/2009] [Accepted: 02/08/2010] [Indexed: 12/25/2022] Open
Abstract
The spirochete Leptospira interrogans is a highly invasive pathogen of worldwide public health importance. Studies from our laboratories and another have demonstrated that L. interrogans can acquire host plasminogen on its surface. Exogenous plasminogen activators can then convert bound plasminogen into the functionally active protease plasmin. In this study, we extend upon those observations and report that leptospiral endostatin-like protein A (LenA) binds human plasminogen in a dose-dependent manner. LenA-plasminogen interactions were significantly inhibited by the lysine analog xi-aminocaproic acid, suggesting that the lysine-binding sites on the amino-terminal kringle portion of the plasminogen molecule play a role in the binding. Previous studies have shown that LenA also binds complement regulator factor H and the extracellular matrix component laminin. Plasminogen competed with both factor H and laminin for binding to LenA, which suggests overlapping ligand-binding sites on the bacterial receptor. Finally, LenA-bound plasminogen could be converted to plasmin, which in turn degraded fibrinogen, suggesting that acquisition of host-derived plasmin by LenA may aid bacterial dissemination throughout host tissues.
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Affiliation(s)
- Ashutosh Verma
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, MN 469 Chandler Medical Center, Lexington, KY 40536-0298, USA.
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Eshghi A, Cullen PA, Cowen L, Zuerner RL, Cameron CE. Global proteome analysis of Leptospira interrogans. J Proteome Res 2010; 8:4564-78. [PMID: 19663501 PMCID: PMC2757032 DOI: 10.1021/pr9004597] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Comparative global proteome analyses were performed on Leptospira interrogans serovar Copenhageni grown under conventional in vitro conditions and those mimicking in vivo conditions (iron limitation and serum presence). Proteomic analyses were conducted using iTRAQ and LC-ESI-tandem mass spectrometry complemented with two-dimensional gel electrophoresis and MALDI-TOF mass spectrometry. A total of 563 proteins were identified in this study. Altered expression of 65 proteins, including upregulation of the L. interrogans virulence factor Loa22 and 5 novel proteins with homology to virulence factors found in other pathogens, was observed between the comparative conditions. Immunoblot analyses confirmed upregulation of 5 of the known or putative virulence factors in L. interrogans exposed to the in vivo-like environmental conditions. Further, ELISA analyses using serum from patients with leptospirosis and immunofluorescence studies performed on liver sections derived from L. interrogans-infected hamsters verified expression of all but one of the identified proteins during infection. These studies, which represent the first documented comparative global proteome analysis of Leptospira, demonstrated proteome alterations under conditions that mimic in vivo infection and allowed for the identification of novel putative L. interrogans virulence factors. The L. interrogans proteome was analyzed using iTRAQ and 2DGE. These analyses identified 563 proteins and altered expression of 65 proteins upon growth of L. interrogans under in vivo-like conditions, including upregulation of the L. interrogans virulence factor Loa22, a putative lipoprotein with primary amino acid sequence similarity to the outer surface protein ErpY of B. burgdorferi, and 4 additional proteins with homology to virulence factors found in other pathogens.
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Affiliation(s)
- Azad Eshghi
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
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Lo M, Cordwell SJ, Bulach DM, Adler B. Comparative transcriptional and translational analysis of leptospiral outer membrane protein expression in response to temperature. PLoS Negl Trop Dis 2009; 3:e560. [PMID: 19997626 PMCID: PMC2780356 DOI: 10.1371/journal.pntd.0000560] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 10/28/2009] [Indexed: 11/19/2022] Open
Abstract
Background Leptospirosis is a global zoonosis affecting millions of people annually. Transcriptional changes in response to temperature were previously investigated using microarrays to identify genes potentially expressed upon host entry. Past studies found that various leptospiral outer membrane proteins are differentially expressed at different temperatures. However, our microarray studies highlighted a divergence between protein abundance and transcript levels for some proteins. Given the abundance of post-transcriptional expression control mechanisms, this finding highlighted the importance of global protein analysis systems. Methodology/Principal Findings To complement our previous transcription study, we evaluated differences in the proteins of the leptospiral outer membrane fraction in response to temperature upshift. Outer membrane protein-enriched fractions from Leptospira interrogans grown at 30°C or overnight upshift to 37°C were isolated and the relative abundance of each protein was determined by iTRAQ analysis coupled with two-dimensional liquid chromatography and tandem mass spectrometry (2-DLC/MS-MS). We identified 1026 proteins with 99% confidence; 27 and 66 were present at elevated and reduced abundance respectively. Protein abundance changes were compared with transcriptional differences determined from the microarray studies. While there was some correlation between the microarray and iTRAQ data, a subset of genes that showed no differential expression by microarray was found to encode temperature-regulated proteins. This set of genes is of particular interest as it is likely that regulation of their expression occurs post-transcriptionally, providing an opportunity to develop hypotheses about the molecular dynamics of the outer membrane of Leptospira in response to changing environments. Conclusions/Significance This is the first study to compare transcriptional and translational responses to temperature shift in L. interrogans. The results thus provide an insight into the mechanisms used by L. interrogans to adapt to conditions encountered in the host and to cause disease. Our results suggest down-regulation of protein expression in response to temperature, and decreased expression of outer membrane proteins may facilitate minimal interaction with host immune mechanisms. Leptospirosis, caused by Leptospira spp., is a disease of worldwide significance affecting millions of people annually. Bacteria of this species are spread by various carrier animals, including rodents and domestic livestock, which shed the leptospires via their urine into the environment. Humans become infected through direct contact with carrier animals or indirectly via contaminated water or soil. Temperature is a key trigger used by many bacteria to sense changes in environmental conditions, including entry from the environment into the host. This study was the first comprehensive research into changes occurring in the outer membrane of Leptospira in response to temperature and how these changes correlate with gene expression changes. An understanding of the regulation and function of these proteins is important as they may provide an adaptation and survival advantage for the microorganism which may enhance its ability to infect hosts and cause disease. Our data suggest regulation of proteins in the outer membrane which may possibly be a mechanism to minimise interactions with the host immune response.
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Affiliation(s)
- Miranda Lo
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Melbourne, Australia
| | - Stuart J. Cordwell
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Melbourne, Australia
- School of Molecular and Microbial Biosciences, University of Sydney, Sydney, Australia
| | - Dieter M. Bulach
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Melbourne, Australia
- Victorian Bioinformatics Consortium, Monash University, Melbourne. Australia
| | - Ben Adler
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Melbourne, Australia
- Victorian Bioinformatics Consortium, Monash University, Melbourne. Australia
- * E-mail: .
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Carvalho E, Barbosa AS, Gómez RM, Oliveira MLS, Romero EC, Gonçales AP, Morais ZM, Vasconcellos SA, Ho PL. Evaluation of the expression and protective potential of Leptospiral sphingomyelinases. Curr Microbiol 2009; 60:134-42. [PMID: 19826861 DOI: 10.1007/s00284-009-9519-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 09/24/2009] [Indexed: 11/25/2022]
Abstract
Leptospirosis is a zoonotic disease of global distribution, which affects both animals and humans. Pathogenic leptospires, the bacteria that cause this disease, require iron for their growth, and these spirochetes probably use their hemolysins, such as the sphingomyelinases, as a way to obtain this important nutrient from host red blood cells during infection. We expressed and purified the leptospiral sphingomyelinases Sph1, Sph2, Sph4, and SphH in a heterologous system. However, the recombinant proteins were not able to lyse sheep erythrocytes, despite having regular secondary structures. Transcripts for all sphingomyelinases tested were detected by RT-PCR analyses, but only Sph2 and SphH native proteins could be detected in Western blot assays using Leptospira whole extracts as well as in renal tubules of infected hamsters. Moreover, antibodies present in the serum of a human patient with laboratory-confirmed leptospirosis recognized Sph2, indicating that this sphingomyelinase is expressed and exposed to the immune system during infection in humans. However, in an animal challenge model, none of the sphingomyelinases tested conferred protection against leptospirosis.
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Affiliation(s)
- Eneas Carvalho
- Centro de Biotecnologia, Instituto Butantan, São Paulo, SP, Brazil
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LruA and LruB antibodies in sera of humans with leptospiral uveitis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2008; 15:1019-23. [PMID: 18400972 DOI: 10.1128/cvi.00203-07] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Uveitis can be a serious complication of leptospirosis. Previous studies indicated that the leptospiral lipoproteins LruA and LruB are expressed in the eyes of uveitic horses and that antibodies directed against those proteins show in vitro cross-reactivity with components of equine lens, ciliary body, and/or retina. We now demonstrate that sera from a significant proportion of humans who have leptospiral uveitis also contain antibodies against LruA and LruB. Different categories of nonleptospiral uveitis and autoimmune uveitis were also screened; patients diagnosed with Fuchs uveitis or Behçet's syndrome produced antibodies that cross-reacted with LruA and LruB, suggesting similarities of the autoimmune responses in those diseases with those of leptospiral uveitis.
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Abstract
Leptospirosis is a serious infection disease caused by pathogenic strains of the Leptospira spirochetes, which affects not only humans but also animals. It has long been expected to find an effective vaccine to prevent leptospirosis through immunization of high risk humans or animals. Although some leptospirosis vaccines have been obtained, the vaccination is relatively unsuccessful in clinical application despite decades of research and millions of dollars spent. In this review, the recent advancements of recombinant outer membrane protein (OMP) vaccines, lipopolysaccharide (LPS) vaccines, inactivated vaccines, attenuated vaccines and DNA vaccines against leptospirosis are reviewed. A comparison of these vaccines may lead to development of new potential methods to combat leptospirosis and facilitate the leptospirosis vaccine research. Moreover, a vaccine ontology database was built for the scientists working on the leptospirosis vaccines as a starting tool.
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Affiliation(s)
- Zhijun Wang
- CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031, Shanghai, PR China.
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31
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Matsunaga J, Medeiros MA, Sanchez Y, Werneid KF, Ko AI. Osmotic regulation of expression of two extracellular matrix-binding proteins and a haemolysin of Leptospira interrogans: differential effects on LigA and Sph2 extracellular release. MICROBIOLOGY-SGM 2007; 153:3390-3398. [PMID: 17906138 DOI: 10.1099/mic.0.2007/007948-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The life cycle of the pathogen Leptospira interrogans involves stages outside and inside the host. Entry of L. interrogans from moist environments into the host is likely to be accompanied by the induction of genes encoding virulence determinants and the concomitant repression of genes encoding products required for survival outside of the host. The expression of the adhesin LigA, the haemolysin Sph2 (Lk73.5) and the outer-membrane lipoprotein LipL36 of pathogenic Leptospira species have been reported to be regulated by mammalian host signals. A previous study demonstrated that raising the osmolarity of the leptospiral growth medium to physiological levels encountered in the host by addition of various salts enhanced the levels of cell-associated LigA and LigB and extracellular LigA. In this study, we systematically examined the effects of osmotic upshift with ionic and non-ionic solutes on expression of the known mammalian host-regulated leptospiral genes. The levels of cell-associated LigA, LigB and Sph2 increased at physiological osmolarity, whereas LipL36 levels decreased, corresponding to changes in specific transcript levels. These changes in expression occurred irrespective of whether sodium chloride or sucrose was used as the solute. The increase of cellular LigA, LigB and Sph2 protein levels occurred within hours of adding sodium chloride. Extracellular Sph2 levels increased when either sodium chloride or sucrose was added to achieve physiological osmolarity. In contrast, enhanced levels of extracellular LigA were observed only with an increase in ionic strength. These results indicate that the mechanisms for release of LigA and Sph2 differ during host infection. Thus, osmolarity not only affects leptospiral gene expression by affecting transcript levels of putative virulence determinants but also affects the release of such proteins into the surroundings.
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Affiliation(s)
- James Matsunaga
- UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
- VA Greater Los Angeles Healthcare System, Research Service, Los Angeles, CA 90073, USA
| | - Marco A Medeiros
- Biomanguinhos, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Rio de Janeiro, Brazil
| | - Yolanda Sanchez
- VA Greater Los Angeles Healthcare System, Research Service, Los Angeles, CA 90073, USA
| | - Kristian F Werneid
- VA Greater Los Angeles Healthcare System, Research Service, Los Angeles, CA 90073, USA
| | - Albert I Ko
- Gonçalo Moniz Research Center, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Brazil
- Division of International Medicine and Infectious Diseases, Weill Medical College of Cornell University, New York, NY 10021, USA
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Stevenson B, Choy HA, Pinne M, Rotondi ML, Miller MC, Demoll E, Kraiczy P, Cooley AE, Creamer TP, Suchard MA, Brissette CA, Verma A, Haake DA. Leptospira interrogans endostatin-like outer membrane proteins bind host fibronectin, laminin and regulators of complement. PLoS One 2007; 2:e1188. [PMID: 18000555 PMCID: PMC2063517 DOI: 10.1371/journal.pone.0001188] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Accepted: 10/24/2007] [Indexed: 11/19/2022] Open
Abstract
The pathogenic spirochete Leptospira interrogans disseminates throughout its hosts via the bloodstream, then invades and colonizes a variety of host tissues. Infectious leptospires are resistant to killing by their hosts' alternative pathway of complement-mediated killing, and interact with various host extracellular matrix (ECM) components. The LenA outer surface protein (formerly called LfhA and Lsa24) was previously shown to bind the host ECM component laminin and the complement regulators factor H and factor H-related protein-1. We now demonstrate that infectious L. interrogans contain five additional paralogs of lenA, which we designated lenB, lenC, lenD, lenE and lenF. All six genes encode domains predicted to bear structural and functional similarities with mammalian endostatins. Sequence analyses of genes from seven infectious L. interrogans serovars indicated development of sequence diversity through recombination and intragenic duplication. LenB was found to bind human factor H, and all of the newly-described Len proteins bound laminin. In addition, LenB, LenC, LenD, LenE and LenF all exhibited affinities for fibronectin, a distinct host extracellular matrix protein. These characteristics suggest that Len proteins together facilitate invasion and colonization of host tissues, and protect against host immune responses during mammalian infection.
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Affiliation(s)
- Brian Stevenson
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America.
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33
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Yu WL, Dan H, Lin M. Novel protein targets of the humoral immune response to Listeria monocytogenes infection in rabbits. J Med Microbiol 2007; 56:888-895. [PMID: 17577052 DOI: 10.1099/jmm.0.46977-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The role of the humoral immune response in protective immunity against listerial infection has been overlooked and is essentially unknown. This study aimed to discover the protein targets of Listeria monocytogenes that elicit an antibody response following infection in a rabbit model. A genomic expression library for L. monocytogenes was constructed and differentially screened to identify genes encoding proteins that reacted with antiserum from rabbits infected with live L. monocytogenes serotype 4b (RalphaL), but not with that from animals immunized with heat-killed bacteria (RalphaK). Thirty-one clones expressing proteins that reacted exclusively with RalphaL were identified and sequenced. Sequence analysis, together with Western blot analysis of the proteins expressed from positive clones, led to the identification of eight L. monocytogenes proteins as targets of humoral immune responses during listerial infection: three internalin members (InlA, InlD and InlC2) and five novel proteins of unknown function (designated IspA, IspB, IspC, IspD and IspE, respectively). Exhibition of humoral immune responses to these proteins in actively infected rabbits but not in animals receiving heat-killed L. monocytogenes suggested that they were induced or significantly upregulated in vivo during infection and thus are important in Listeria pathogenesis. With the exception of antibodies to InlA, this is the first demonstration of antibodies to the other seven proteins in infected hosts. These immunogenic proteins may be useful candidates for elucidation of the role of antibodies in protective immunity in the context of listerial infection, as well as potential targets for serodiagnostic reagents and vaccine and drug development.
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Affiliation(s)
- Wei Ling Yu
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Animal Diseases Research Institute, Ottawa, ON K2H 8P9, Canada
| | - Hanhong Dan
- Animal Diseases Research Institute, Ottawa, ON K2H 8P9, Canada
| | - Min Lin
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Animal Diseases Research Institute, Ottawa, ON K2H 8P9, Canada
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Abstract
PURPOSE OF REVIEW Leptospirosis is among the most important zoonotic diseases worldwide. Completion of the genomic sequences of leptospires has facilitated advances in diagnosis and prevention of the disease, and yielded insight into its pathogenesis. This article reviews this research, emphasizing recent progress. RECENT FINDINGS Leptospirosis is caused by a group of highly invasive spiral bacteria (spirochetes) that can infect both people and animals. Spirochetes can survive in the environment and host, and therefore outer membrane and secretory proteins that interact with the host are of considerable interest in leptospire research. The genetic approach to studying pathogenesis is hindered by fastidious growth of pathogenic leptospires. Integrated genomic and proteomic approaches, however, have yielded enhanced understanding of the pathogenesis of leptospirosis. Furthermore, studies of innate immune response to the organism have enhanced our understanding of host susceptibility and resistance to infection. In-silico analysis and high-throughput cloning and expression have had major impacts on efforts to develop vaccine candidates and diagnostic reagents. SUMMARY In the future, we must effectively utilize the wealth of genetic information to combat the disease. More studies into genetics, immune mechanisms that may be exploited to prevent leptospirosis, and pathogenesis of the disease are necessary.
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Affiliation(s)
- Raghavan U M Palaniappan
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA.
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35
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Matsunaga J, Lo M, Bulach DM, Zuerner RL, Adler B, Haake DA. Response of Leptospira interrogans to physiologic osmolarity: relevance in signaling the environment-to-host transition. Infect Immun 2007; 75:2864-74. [PMID: 17371863 PMCID: PMC1932867 DOI: 10.1128/iai.01619-06] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Transmission of pathogenic Leptospira between mammalian hosts usually involves dissemination via soil or water contaminated by the urine of carrier animals. The ability of Leptospira to adapt to the diverse conditions found inside and outside the host is reflected in its relatively large genome size and high percentage of signal transduction genes. An exception is Leptospira borgpetersenii serovar Hardjo, which is transmitted by direct contact and appears to have lost genes necessary for survival outside the mammalian host. Invasion of host tissues by Leptospira interrogans involves a transition from a low osmolar environment outside the host to a higher physiologic osmolar environment within the host. Expression of the lipoprotein LigA and LigB adhesins is strongly induced by an upshift in osmolarity to the level found in mammalian host tissues. These data suggest that Leptospira utilizes changes in osmolarity to regulate virulence characteristics. To better understand how L. interrogans serovar Copenhageni adapts to osmolar conditions that correspond with invasion of a mammalian host, we quantified alterations in transcript levels using whole-genome microarrays. Overnight exposure in leptospiral culture medium supplemented with sodium chloride to physiologic osmolarity significantly altered the transcript levels of 6% of L. interrogans genes. Repressed genes were significantly more likely to be absent or pseudogenes in L. borgpetersenii, suggesting that osmolarity is relevant in studying the adaptation of L. interrogans to host conditions. Genes induced by physiologic osmolarity encoded a higher than expected number of proteins involved in signal transduction. Further, genes predicted to encode lipoproteins and those coregulated by temperature were overrepresented among both salt-induced and salt-repressed genes. In contrast, leptospiral homologues of hyperosmotic or general stress genes were not induced at physiologic osmolarity. These findings suggest that physiologic osmolarity is an important signal for regulation of gene expression by pathogenic leptospires during transition from ambient conditions to the host tissue environment.
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Affiliation(s)
- James Matsunaga
- Research Service, VA Greater Los Angeles Healthcare System, Los Angeles, CA 90073, USA.
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36
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Lo M, Bulach DM, Powell DR, Haake DA, Matsunaga J, Paustian ML, Zuerner RL, Adler B. Effects of temperature on gene expression patterns in Leptospira interrogans serovar Lai as assessed by whole-genome microarrays. Infect Immun 2006; 74:5848-59. [PMID: 16988264 PMCID: PMC1594916 DOI: 10.1128/iai.00755-06] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Leptospirosis is an important zoonosis of worldwide distribution. Humans become infected via exposure to pathogenic Leptospira spp. from infected animals or contaminated water or soil. The availability of genome sequences for Leptospira interrogans, serovars Lai and Copenhageni, has opened up opportunities to examine global transcription profiles using microarray technology. Temperature is a key environmental factor known to affect leptospiral protein expression. Leptospira spp. can grow in artificial media at a range of temperatures reflecting conditions found in the environment and the mammalian host. Therefore, transcriptional changes were compared between cultures grown at 20 degrees C, 30 degrees C, 37 degrees C, and 39 degrees C to represent ambient temperatures in the environment, growth under laboratory conditions, and temperatures in healthy and febrile hosts. Data from direct pairwise comparisons of the four temperatures were consolidated to examine transcriptional changes at two generalized biological conditions representing mammalian physiological temperatures (37 degrees C and 39 degrees C) versus environmental temperatures (20 degrees C and 30 degrees C). Additionally, cultures grown at 30 degrees C then shifted overnight to 37 degrees C were compared with those grown long-term at 30 degrees C and 37 degrees C to identify genes potentially expressed in the early stages of infection. Comparison of data sets from physiological versus environmental experiments with upshift experiments provided novel insights into possible transcriptional changes at different stages of infection. Changes included differential expression of chemotaxis and motility genes, signal transduction systems, and genes encoding proteins involved in alteration of the outer membrane. These findings indicate that temperature is an important factor regulating expression of proteins that facilitate invasion and establishment of disease.
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Affiliation(s)
- Miranda Lo
- Department of Microbiology, Monash University, Victoria 3800, Australia
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Verma A, Hellwage J, Artiushin S, Zipfel PF, Kraiczy P, Timoney JF, Stevenson B. LfhA, a novel factor H-binding protein of Leptospira interrogans. Infect Immun 2006; 74:2659-66. [PMID: 16622202 PMCID: PMC1459737 DOI: 10.1128/iai.74.5.2659-2666.2006] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2005] [Revised: 01/02/2006] [Accepted: 02/01/2006] [Indexed: 11/20/2022] Open
Abstract
The early phase of leptospiral infection is characterized by the presence of live organisms in the blood. Pathogenic Leptospira interrogans is resistant to the alternative pathway of complement mediated-killing, while nonpathogenic members of the genus are not. Consistent with that observation, only pathogenic leptospires bound factor H, a host fluid-phase regulator of the alternative complement pathway. Ligand affinity blot analyses revealed that pathogenic L. interrogans produces at least two factor H-binding proteins. Through screening of a lambda phage expression library, we identified one of these as the novel membrane protein LfhA. Ligand affinity assays and surface plasmon resonance analyses of recombinant LfhA revealed specific binding of both factor H and factor H-related protein 1. Serological examination of infected humans and horses demonstrated that LfhA is expressed by L. interrogans during mammalian infection. LfhA may therefore contribute to the resistance of pathogenic leptospires to complement-mediated killing during leptospiremic phases of the disease.
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Affiliation(s)
- Ashutosh Verma
- Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA
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Verma A, Artiushin S, Matsunaga J, Haake DA, Timoney JF. LruA and LruB, novel lipoproteins of pathogenic Leptospira interrogans associated with equine recurrent uveitis. Infect Immun 2005; 73:7259-66. [PMID: 16239521 PMCID: PMC1273856 DOI: 10.1128/iai.73.11.7259-7266.2005] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Recurrent uveitis as a sequela to Leptospira infection is the most common infectious cause of blindness and impaired vision of horses worldwide. Leptospiral proteins expressed during prolonged survival in the eyes of horses with lesions of chronic uveitis were identified by screening a phage library of Leptospira interrogans DNA fragments with eye fluids from uveitic horses. Inserts of reactive phages encoded several known leptospiral proteins and two novel putative lipoproteins, LruA and LruB. LruA was intrinsically labeled during incubation of L. interrogans in medium containing [14C]palmitic acid, confirming that it is a lipoprotein. lruA and lruB were detected by Southern blotting in infectious Leptospira interrogans but not in nonpathogenic Leptospira biflexa. Fractionation data from cultured Leptospira indicate that LruA and LruB are localized in the inner membrane. Uveitic eye fluids contained significantly higher levels of immunoglobulin A (IgA) and IgG specific for each protein than did companion sera, indicating strong local antibody responses. Moreover, LruA- and LruB-specific antisera reacted with equine ocular components, suggesting an immunopathogenic role in leptospiral uveitis.
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Affiliation(s)
- Ashutosh Verma
- M. H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA
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