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Santecchia I, Bonhomme D, Papadopoulos S, Escoll P, Giraud-Gatineau A, Moya-Nilges M, Vernel-Pauillac F, Boneca IG, Werts C. Alive Pathogenic and Saprophytic Leptospires Enter and Exit Human and Mouse Macrophages With No Intracellular Replication. Front Cell Infect Microbiol 2022; 12:936931. [PMID: 35899053 PMCID: PMC9310662 DOI: 10.3389/fcimb.2022.936931] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 06/14/2022] [Indexed: 02/03/2023] Open
Abstract
Leptospira interrogans are pathogenic bacteria responsible for leptospirosis, a zoonosis impacting 1 million people per year worldwide. Leptospires can infect all vertebrates, but not all hosts develop similar symptoms. Human and cattle may suffer from mild to acute illnesses and are therefore considered as sensitive to leptospirosis. In contrast, mice and rats remain asymptomatic upon infection, although they get chronically colonized in their kidneys. Upon infection, leptospires are stealth pathogens that partially escape the recognition by the host innate immune system. Although leptospires are mainly extracellular bacteria, it was suggested that they could also replicate within macrophages. However, contradictory data in the current literature led us to reevaluate these findings. Using a gentamicin–protection assay coupled to high-content (HC) microscopy, we observed that leptospires were internalized in vivo upon peritoneal infection of C57BL/6J mice. Additionally, three different serotypes of pathogenic L. interrogans and the saprophytic L. biflexa actively infected both human (PMA differentiated) THP1 and mouse RAW264.7 macrophage cell lines. Next, we assessed the intracellular fate of leptospires using bioluminescent strains, and we observed a drastic reduction in the leptospiral intracellular load between 3 h and 6 h post-infection, suggesting that leptospires do not replicate within these cells. Surprisingly, the classical macrophage microbicidal mechanisms (phagocytosis, autophagy, TLR–mediated ROS, and RNS production) were not responsible for the observed decrease. Finally, we demonstrated that the reduction in the intracellular load was associated with an increase of the bacteria in the supernatant, suggesting that leptospires exit both human and murine macrophages. Overall, our study reevaluated the intracellular fate of leptospires and favors an active entrance followed by a rapid exit, suggesting that leptospires do not have an intracellular lifestyle in macrophages.
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Affiliation(s)
- Ignacio Santecchia
- Institut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, France
| | - Delphine Bonhomme
- Institut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, France
| | - Stylianos Papadopoulos
- Institut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, France
| | - Pedro Escoll
- Institut Pasteur, Université Cité Paris, CNRS UMR6047, Unité Biologie des Bactéries Intracellulaires, Paris, France
| | - Alexandre Giraud-Gatineau
- Institut Pasteur, Université Cité Paris, CNRS UMR6047, Unité de Biologie des Spirochètes, Paris, France
| | - Maryse Moya-Nilges
- Institut Pasteur, Université Cité Paris, Plateforme de Bio-imagerie Ultrastructurale, Paris, France
| | - Frédérique Vernel-Pauillac
- Institut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, France
| | - Ivo Gomperts Boneca
- Institut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, France
| | - Catherine Werts
- Institut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, France
- *Correspondence: Catherine Werts,
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Santecchia I, Ferrer MF, Vieira ML, Gómez RM, Werts C. Phagocyte Escape of Leptospira: The Role of TLRs and NLRs. Front Immunol 2020; 11:571816. [PMID: 33123147 PMCID: PMC7573490 DOI: 10.3389/fimmu.2020.571816] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/16/2020] [Indexed: 12/21/2022] Open
Abstract
The spirochetal bacteria Leptospira spp. are causative agents of leptospirosis, a globally neglected and reemerging zoonotic disease. Infection with these pathogens may lead to an acute and potentially fatal disease but also to chronic asymptomatic renal colonization. Both forms of disease demonstrate the ability of leptospires to evade the immune response of their hosts. In this review, we aim first to recapitulate the knowledge and explore the controversial data about the opsonization, recognition, intracellular survival, and killing of leptospires by scavenger cells, including platelets, neutrophils, macrophages, and dendritic cells. Second, we will summarize the known specificities of the recognition or escape of leptospire components (the so-called microbial-associated molecular patterns; MAMPs) by the pattern recognition receptors (PRRs) of the Toll-like and NOD-like families. These PRRs are expressed by phagocytes, and their stimulation by MAMPs triggers pro-inflammatory cytokine and chemokine production and bactericidal responses, such as antimicrobial peptide secretion and reactive oxygen species production. Finally, we will highlight recent studies suggesting that boosting or restoring phagocytic functions by treatments using agonists of the Toll-like or NOD receptors represents a novel prophylactic strategy and describe other potential therapeutic or vaccine strategies to combat leptospirosis.
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Affiliation(s)
- Ignacio Santecchia
- Institut Pasteur, Microbiology Department, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie intégrative et Moléculaire, Paris, France.,INSERM, Equipe Avenir, Paris, France.,Université de Paris, Sorbonne Paris Cité, Paris, France
| | - María Florencia Ferrer
- Laboratorio de Virus Animales, Instituto de Biotecnología y Biología Molecular, CONICET-Universidad Nacional de La Plata, La Plata, Argentina
| | - Monica Larucci Vieira
- Departamento de Microbiologia, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Ricardo Martín Gómez
- Laboratorio de Virus Animales, Instituto de Biotecnología y Biología Molecular, CONICET-Universidad Nacional de La Plata, La Plata, Argentina
| | - Catherine Werts
- Institut Pasteur, Microbiology Department, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie intégrative et Moléculaire, Paris, France
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Santecchia I, Vernel-Pauillac F, Rasid O, Quintin J, Gomes-Solecki M, Boneca IG, Werts C. Innate immune memory through TLR2 and NOD2 contributes to the control of Leptospira interrogans infection. PLoS Pathog 2019; 15:e1007811. [PMID: 31107928 PMCID: PMC6544334 DOI: 10.1371/journal.ppat.1007811] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 05/31/2019] [Accepted: 05/02/2019] [Indexed: 12/25/2022] Open
Abstract
Leptospira interrogans are pathogenic spirochetes responsible for leptospirosis, a worldwide reemerging zoonosis. Many Leptospira serovars have been described, and prophylaxis using inactivated bacteria provides only short-term serovar-specific protection. Therefore, alternative approaches to limit severe leptospirosis in humans and morbidity in cattle would be welcome. Innate immune cells, including macrophages, play a key role in fighting infection and pathogen clearance. Recently, it has been shown that functional reprograming of innate immune cells through the activation of pattern recognition receptors leads to enhanced nonspecific antimicrobial responses upon a subsequent microbial encounter. This mechanism is known as trained immunity or innate immune memory. We have previously shown that oral treatment with Lactobacillus plantarum confers a beneficial effect against acute leptospirosis. Here, using a macrophage depletion protocol and live imaging in mice, we established the role of peritoneal macrophages in limiting the initial dissemination of leptospires. We further showed that intraperitoneal priming of mice with CL429, a TLR2 and NOD2 agonist known to mimic the modulatory effect of Lactobacillus, alleviated acute leptospiral infection. The CL429 treatment was characterized as a training effect since i.) it was linked to peritoneal macrophages that produced ex vivo more pro-inflammatory cytokines and chemokines against 3 different pathogenic serovars of Leptospira, independently of the presence of B and T cells, ii.) it had systemic effects on splenic cells and bone marrow derived macrophages, and iii.) it was sustained for 3 months. Importantly, trained macrophages produced more nitric oxide, a potent antimicrobial compound, which has not been previously linked to trained immunity. Accordingly, trained macrophages better restrict leptospiral survival. Finally, we could use CL429 to train ex vivo human monocytes that produced more cytokines upon leptospiral stimulation. In conclusion, host-directed treatment using a TLR2/NOD2 agonist could be envisioned as a novel prophylactic strategy against acute leptospirosis.
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Affiliation(s)
- Ignacio Santecchia
- Unité Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur, Groupe Avenir, INSERM, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Frédérique Vernel-Pauillac
- Unité Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur, Groupe Avenir, INSERM, Paris, France
| | - Orhan Rasid
- Chromatine et Infection G5, Institut Pasteur, Paris, France
| | - Jessica Quintin
- Immunologie des infections fongiques G5, Institut Pasteur, Paris, France
| | - Maria Gomes-Solecki
- University of Tennessee Health Science Center, Department of Microbiology, Immunology and Biochemistry, Memphis, Tennessee, United States of America
| | - Ivo G. Boneca
- Unité Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur, Groupe Avenir, INSERM, Paris, France
| | - Catherine Werts
- Unité Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur, Groupe Avenir, INSERM, Paris, France
- * E-mail:
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Ferrer MF, Scharrig E, Charo N, Rípodas AL, Drut R, Carrera Silva EA, Nagel A, Nally JE, Montes de Oca DP, Schattner M, Gómez RM. Macrophages and Galectin 3 Control Bacterial Burden in Acute and Subacute Murine Leptospirosis That Determines Chronic Kidney Fibrosis. Front Cell Infect Microbiol 2018; 8:384. [PMID: 30425972 PMCID: PMC6218566 DOI: 10.3389/fcimb.2018.00384] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 10/11/2018] [Indexed: 12/15/2022] Open
Abstract
Previous studies have suggested that macrophages may contribute to acute Leptospira dissemination, as well as having a major role in kidney fibrosis. Our aim was to characterize the role of macrophages and galectin 3 (Gal-3) on the survival, clinical course, bacterial burden, interstitial nephritis, and chronic kidney fibrosis in Leptospira interrogans serovar Copenhageni (LIC)-induced experimental murine leptospirosis. C57BL/6J mice depleted of macrophages by liposome-encapsulated clodronate treatment and infected with LIC presented a higher bacterial burden, had reduced subacute nephritis and enhanced chronic kidney fibrosis relative to untreated, infected mice. Moreover, LIC infection in mice whose Gal-3 was disrupted (Lgals3−/–) had a higher bacterial burden and enhanced subacute nephritis and chronic kidney fibrosis when compared to C57BL/6J wild-type mice. Chronic fibrosis did not correlate with higher transcription levels of TGF-β1 or IL-13 in the kidneys. Kidney fibrosis was found in chronically infected rats as well as in wild infected rats. On the other hand, human fibroblast cultures exhibited enhanced differentiation to myofibroblasts after treatment with LIC. Our results demonstrate that macrophages and Gal-3 play a critical role in controlling the LIC burden but has a minor role in subsequent fibrosis. Instead, kidney fibrosis was better correlated with bacterial burden. Taken together, our results do not support a role for macrophages to disseminate leptospires during acute infection, nor in chronic kidney fibrosis.
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Affiliation(s)
- María F Ferrer
- Laboratory of Animal Viruses, Institute of Biotechnology and Molecular Biology, UNLP-CONICET, La Plata, Argentina
| | - Emilia Scharrig
- Laboratory of Animal Viruses, Institute of Biotechnology and Molecular Biology, UNLP-CONICET, La Plata, Argentina
| | - Nancy Charo
- Laboratory of Experimental Thrombosis, Institute of Experimental Medicine, National Academy of Medicine-CONICET, Buenos Aires, Argentina
| | | | - Ricardo Drut
- Division of Pathology, Children Hospital "Superiora Sor María Ludovica", La Plata, Argentina
| | - Eugenio A Carrera Silva
- Laboratory of Experimental Thrombosis, Institute of Experimental Medicine, National Academy of Medicine-CONICET, Buenos Aires, Argentina
| | - Ariel Nagel
- Biotechnology Institute, National Institute of Agricultural Technology (INTA-CONICET), Buenos Aires, Argentina
| | - Jarlath E Nally
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Pullman, WA, United States
| | - Daniela P Montes de Oca
- Ecology, Genetics and Evolution Department, Exact and Natural Sciences Faculty, and Ecology, Genetics and Evolution Institute of Buenos Aires, UBA-CONICET, Buenos Aires, Argentina
| | - Mirta Schattner
- Laboratory of Experimental Thrombosis, Institute of Experimental Medicine, National Academy of Medicine-CONICET, Buenos Aires, Argentina
| | - Ricardo M Gómez
- Laboratory of Animal Viruses, Institute of Biotechnology and Molecular Biology, UNLP-CONICET, La Plata, Argentina
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Masuzawa T, Nakamura R, Shimizu T, Iwamoto Y, Morita T, Yanagihara Y. Immunological characteristics of the glycolipid antigen of Leptospira interrogans serovar lai. Infect Immun 1989; 57:2502-6. [PMID: 2744857 PMCID: PMC313477 DOI: 10.1128/iai.57.8.2502-2506.1989] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The protective antigen (PAg), a glycolipid substance, was extracted from Leptospira interrogans serovar lai strain 017 with a chloroform-methanol-water (1:2:0.8 [vol/vol/vol]) solution and partially purified by silica gel column chromatography. The PAg was not detected by Coomassie brilliant blue staining in sodium dodecyl sulfate-polyacrylamide gel electrophoresis but was observed as a smearlike band, which corresponded to a 24- to 30-kilodalton standard protein, by silver staining. The outer envelope (OE) fraction showed the same band, suggesting that the PAg was one of the chemical components of the OE. The immunogenicity and protective activity of the PAg were compared with those of the OE. The PAg as well as the OE and whole cells was able to induce agglutinating antibody against L. interrogans. Furthermore, the immune sera exhibited opsonic activity against L. interrogans, as observed by measurement of chemical luminescence derived from reactive oxygen. The PAg exhibited protective activity in hamsters challenged with lethal doses of L. interrogans. Therefore, the antigen may be useful as a component vaccine against leptospiral infection.
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Affiliation(s)
- T Masuzawa
- Department of Microbiology, School of Pharmaceutical Sciences, University of Shizuoka, Japan
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