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Kundu S, Shetty A, Gomes-Solecki M. Exposure to live saprophytic Leptospira before challenge with a pathogenic serovar prevents severe leptospirosis and promotes kidney homeostasis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.01.582981. [PMID: 38496604 PMCID: PMC10942337 DOI: 10.1101/2024.03.01.582981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Previous studies demonstrated that Leptospira biflexa, a saprophytic species, triggers innate immune responses in the host during early infection. This raised the question of whether these responses could suppress a subsequent challenge with pathogenic Leptospira. We inoculated C3H/HeJ mice with a single or a double dose of L. biflexa before challenge with a pathogenic serovar, L. interrogans serovar Copenhageni FioCruz (LIC). Pre-challenge exposure to L. biflexa did not prevent LIC dissemination and colonization of the kidney. However, it rescued weight loss and mouse survival thereby mitigating disease severity. Unexpectedly, there was correlation between rescue of overall health (weight gain, higher survival, lower kidney fibrosis marker ColA1) and higher shedding of LIC in urine. This stood in contrast to the L. biflexa unexposed LIC challenged control. Immune responses were dominated by increased frequency of effector T helper (CD4+) cells in spleen, as well as significant increases in serologic IgG2a. Our findings suggest that exposure to live saprophytic Leptospira primes the host to develop Th1 biased immune responses that prevent severe disease induced by a subsequent challenge with a pathogenic species. Thus, mice exposed to live saprophytic Leptospira before facing a pathogenic serovar may withstand infection with far better outcomes. Furthermore, a status of homeostasis may have been reached after kidney colonization that helps LIC complete its enzootic cycle.
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Affiliation(s)
- Suman Kundu
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Advait Shetty
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Maria Gomes-Solecki
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
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Liu YH, Chen YH, Chen CM. Fulminant Leptospirosis Presenting with Rapidly Developing Acute Renal Failure and Multiorgan Failure. Biomedicines 2024; 12:435. [PMID: 38398036 PMCID: PMC10886720 DOI: 10.3390/biomedicines12020435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 02/08/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024] Open
Abstract
Leptospirosis, caused by pathogenic spirochetes of the Leptospira genus, is a common zoonosis in tropical and subtropical regions and can lead to an epidemic following heavy rainfall or flooding. The primary reservoirs of Leptospira include rodents, wild animals, dogs, cats, amphibians, and others, but the brown rat (Rattus norvegicus) remains the main source of human Leptospirosis. Humans are often accidental hosts and they can be infected through cuts, abrasions, mucosa, conjunctiva, or by ingesting contaminated water. The clinical manifestation of leptospirosis can vary from mild, nonspecific symptoms to a fatal outcome involving liver and renal failure, pulmonary hemorrhage, meningitis, and septic shock. The severity of fatal outcomes is likely to be due to virulence factors, host susceptibility, and epidemiological conditions. L. interrogans are associated with high-risk individuals, particularly patients older than 60 years of age in clinical settings. The current case study showed a foreign worker who presented with rapidly deteriorating clinical signs of fever, jaundice, impaired consciousness, and oliguric acute renal failure. Drawing from our experience, it is advisable to consider the possibility of leptospirosis diagnosis in patients who show clinical symptoms such as fever, hepatic failure with jaundice, and acute renal failure. This is particularly important for those individuals with a prior history of pathogen exposure. This case study had a strong suspicion of leptospirosis, which was confirmed by the microscopic agglutination test (MAT) and, later, the patient's recovery following treatment.
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Affiliation(s)
- Yu-Hsien Liu
- Department of Life Sciences, Doctorial Program in Translational Medicine, National Chung Hsing University, Taichung 402, Taiwan; (Y.-H.L.); (Y.-H.C.)
- Department of Internal Medicine, Jen-Ai Hospital, Dali Branch, Jen-Ai Medical Foundation and Chang Gung Medical Foundation Cooperation Alliance, Taichung 402, Taiwan
| | - Yu-Hsuan Chen
- Department of Life Sciences, Doctorial Program in Translational Medicine, National Chung Hsing University, Taichung 402, Taiwan; (Y.-H.L.); (Y.-H.C.)
- Department of Internal Medicine, Jen-Ai Hospital, Dali Branch, Jen-Ai Medical Foundation and Chang Gung Medical Foundation Cooperation Alliance, Taichung 402, Taiwan
| | - Chuan-Mu Chen
- Department of Life Sciences, Doctorial Program in Translational Medicine, National Chung Hsing University, Taichung 402, Taiwan; (Y.-H.L.); (Y.-H.C.)
- The iEGG and Animal Biotechnology Research Center, The Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung 402, Taiwan
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Miyahara S, Mori H, Fukuda K, Ogawa M, Saito M. Non-purulent myositis caused by direct invasion of skeletal muscle tissue by Leptospira in a hamster model. Infect Immun 2024; 92:e0042023. [PMID: 38240601 PMCID: PMC10870730 DOI: 10.1128/iai.00420-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/22/2023] [Indexed: 02/15/2024] Open
Abstract
Myalgia is a common symptom of Leptospira infection in humans. Autopsies have reported that muscle tissue shows degeneration and necrosis of the myofibers and infiltration of inflammatory cells composed mainly of macrophages and lymphocytes. It remains unclear whether Leptospira directly infects the muscle and how the infiltrating inflammatory cells are involved in muscle fiber destruction. This study evaluated the relationship between histopathological changes and leptospiral localization in the muscle tissue of a hamster model. The influence of macrophages in skeletal muscle injury was also investigated, using selective depletion of macrophages by administration of liposomal clodronate. Hamsters infected subcutaneously with Leptospira interrogans serovar Manilae strain UP-MMC-SM showed myositis of the thighs adjacent to the inoculated area beginning at 6 days post-infection. The myositis was non-purulent and showed sporadic degeneration and necrosis of muscle fibers. The degeneration of myofibers was accompanied by aggregations of macrophages. Immunofluorescence staining revealed leptospires surrounding the damaged muscle fibers. Subcutaneous injection of formalin-killed Leptospira or intraperitoneal injection of live Leptospira caused no myositis in hamster thighs. Liposomal clodronate treatment in infected hamsters reduced macrophage infiltration in muscle tissue without impacting bacterial clearance. Muscle necrosis was still observed in the infected hamsters treated with liposomal clodronate, and there was no significant change in serum creatine kinase levels compared to those in animals treated with liposomes alone. Our findings suggest that leptospiral invasion of muscle tissue from an inoculation site leads to the destruction of muscle fibers and causes non-purulent myositis, whereas the infiltrating macrophages contribute less to muscle destruction.
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Affiliation(s)
- Satoshi Miyahara
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Hiroshi Mori
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
- Department of Obstetrics and Gynecology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Kazumasa Fukuda
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Midori Ogawa
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Mitsumasa Saito
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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Krangvichian P, Techawiwattanaboon T, Palaga T, Ritprajak P, Kueanjinda P, Kaewraemruaen C, Patarakul K. Impaired functions of human monocyte-derived dendritic cells and induction of regulatory T cells by pathogenic Leptospira. PLoS Negl Trop Dis 2023; 17:e0011781. [PMID: 37983293 PMCID: PMC10695387 DOI: 10.1371/journal.pntd.0011781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 12/04/2023] [Accepted: 11/08/2023] [Indexed: 11/22/2023] Open
Abstract
Leptospirosis is a global zoonosis caused by pathogenic Leptospira. The disease outcome is influenced by the interplay between innate and adaptive immune responses. Dendritic cells (DCs) play a crucial role in shaping the adaptive immune response. A recent study revealed that pathogenic Leptospira limited the activation of human monocyte-derived dendritic cells (MoDCs) compared to non-pathogenic Leptospira, but their impact on T-cell responses has not been investigated. Our study is the first to explore how viable pathogenic and non-pathogenic Leptospira affect the interaction between human MoDCs and T cells. We found that MoDCs infected with pathogenic leptospires (L. interrogans serovar Pomona and a clinical isolate, MoDCs-P) exhibited lower levels of CD80 and CD83 expression, suggesting partially impaired MoDC maturation, induced regulatory T cells (Tregs) while failing to induce CD4+ T cell proliferation, compared to MoDCs infected with non-pathogenic leptospires (L. biflexa serovar Patoc and L. meyeri serovar Ranarum, MoDCs-NP). In contrast, non-pathogenic leptospires enhanced MoDC maturation and induced higher T cell proliferation including IFN-γ-producing CD4+ T cells, indicative of a Th1-type response. Furthermore, pathogenic leptospires induced higher MoDC apoptosis through a cysteine aspartic acid-specific protease-3 (caspase-3)-dependent pathway and upregulated expression of the prostaglandin-endoperoxide synthase 2 (PTGS2) gene. Notably, prostaglandin E2 (PGE2), a product of the PTGS2 pathway, was found at higher levels in the sera of patients with acute leptospirosis and in the supernatant of MoDCs-P, possibly contributing to Treg induction, compared to those of healthy donors and MoDCs-NP, respectively. In conclusion, this study reveals a novel immunosuppressive strategy employed by pathogenic Leptospira to evade host immunity by partially impairing MoDC maturation and inducing Tregs. These findings deepen our understanding of leptospirosis pathogenesis in humans and may provide a novel strategy to modulate DCs for the prevention and treatment of the disease.
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Affiliation(s)
- Pratomporn Krangvichian
- Medical Microbiology, Interdisciplinary Program, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Teerasit Techawiwattanaboon
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
| | - Tanapat Palaga
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Patcharee Ritprajak
- Research Unit in Integrative Immuno-Microbial Biochemistry and Bioresponsive Nanomaterials, Department of Microbiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Patipark Kueanjinda
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Chamraj Kaewraemruaen
- Department of Science and Bioinnovation, Faculty of Liberal Arts and Science, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom, Thailand
| | - Kanitha Patarakul
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
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Wang X, Bi C, Xin X, Zhang M, Fu H, Lan L, Wang M, Yan Z. Pyroptosis, apoptosis, and autophagy are involved in infection induced by two clinical Klebsiella pneumoniae isolates with different virulence. Front Cell Infect Microbiol 2023; 13:1165609. [PMID: 37223846 PMCID: PMC10200925 DOI: 10.3389/fcimb.2023.1165609] [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: 02/14/2023] [Accepted: 04/18/2023] [Indexed: 05/25/2023] Open
Abstract
Klebsiella pneumoniae can cause widespread infections and is an important factor of hospital- and community-acquired pneumonia. The emergence of hypervirulent K. pneumoniae poses a serious clinical therapeutic challenge and is associated with a high mortality. The goal of this work was to investigate the influence of K. pneumoniae infection on host cells, particularly pyroptosis, apoptosis, and autophagy in the context of host-pathogen interactions to better understand the pathogenic mechanism of K. pneumoniae. Two clinical K. pneumoniae isolates, one classical K. pneumoniae isolate and one hypervirulent K. pneumoniae isolate, were used to infect RAW264.7 cells to establish an in vitro infection model. We first examined the phagocytosis of macrophages infected with K. pneumoniae. Lactate dehydrogenase (LDH) release test, and calcein-AM/PI double staining was conducted to determine the viability of macrophages. The inflammatory response was evaluated by measuring the pro-inflammatory cytokines and reactive oxygen species (ROS) production. The occurrence of pyroptosis, apoptosis, and autophagy was assessed by detecting the mRNA and protein levels of the corresponding biochemical markers. In addition, mouse pneumonia models were constructed by intratracheal instillation of K. pneumoniae for in vivo validation experiments. As for results, hypervirulent K. pneumoniae was much more resistant to macrophage-mediated phagocytosis but caused more severe cellular damage and lung tissues damage compared with classical K. pneumoniae. Moreover, we found increased expression of NLRP3, ASC, caspase-1, and GSDMD associated with pyroptosis in macrophages and lung tissues, and the levels were much higher following hypervirulent K. pneumoniae challenge. Both strains induced apoptosis in vitro and in vivo; the higher apoptosis proportion was observed in infection caused by hypervirulent K. pneumoniae. Furthermore, classical K. pneumoniae strongly triggered autophagy, while hypervirulent K. pneumoniae weakly activated this process. These findings provide novel insights into the pathogenesis of K. pneumoniae and may form the foundation for the future design of treatments for K. pneumoniae infection.
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Affiliation(s)
- Xueting Wang
- Institute of Medical Faculty, Qingdao University, Qingdao, China
| | - Chunxia Bi
- Department of Clinical Laboratory, Qingdao Municipal Hospital, Qingdao, China
| | - Xiaoni Xin
- Department of Clinical Laboratory, Qingdao Municipal Hospital, Qingdao, China
| | - Mengmeng Zhang
- Department of Clinical Laboratory, Shandong Provincial Second People’s Hospital, Jinan, China
| | - Hengxia Fu
- Department of Clinical Laboratory, Linyi Central Hospital, Linyi, China
| | - Lei Lan
- Department of Blood Transfusion, Qingdao Women and Children’s Hospital, Qingdao, China
| | - Mengyuan Wang
- Department of Clinical Laboratory, Jinan Children’s Hospital, Jinan, China
| | - Zhiyong Yan
- College of Basic Medicine, Medical Faculty of Qingdao University, Qingdao, China
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Sumaiya K, Selvambika P, Natarajaseenivasan K. Anti-macrophage migration inhibitory factor (MIF) activity of ibudilast: A repurposing drug attenuates the pathophysiology of leptospirosis. Microb Pathog 2022; 173:105786. [PMID: 36150555 DOI: 10.1016/j.micpath.2022.105786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/08/2022] [Accepted: 09/14/2022] [Indexed: 11/28/2022]
Abstract
To develop the macrophage migration inhibitory factor (MIF) directed therapeutic approach for the treatment of leptospirosis, we identified potential MIF inhibitors by screening 10 essential tautomerase inhibition classes of chemical compounds and 7 existing anti-inflammatory and anti-microbial drugs. Dopachrome tautomerase assay was performed to measure the anti-MIF activity of selected compounds. Among 17 chemical compounds, ibudilast, an anti-inflammatory agent showed the MIF tautomerase IC50 value at a very lower concentration (9.5 ± 5.6 μM) which is considered similar to the IC50 of standard MIF antagonist, ISO-1 (6.2 ± 3.8 μM) with non-significant cytotoxicity. The in vitro analysis of the therapeutic potential of MIF inhibitor revealed that ibudilast significantly reduced the leptospiral lipopolysaccharide (LPS) mediated expression of inflammatory mediators such as intercellular adhesion molecule (ICAM), p38 and p44/42 mitogen-activated protein kinase (MAPK), inflammatory cytokines, and decreased the reactive oxygen species (ROS) production, mitochondrial membrane potential (ΔΨm) loss and cell death of LPS treated THP-1 cells. In vivo analysis demonstrated that the administration of anti-MIF Ibudilast significantly reduced the histopathological changes, downregulates the pro-inflammatory cytokines, and protects the leptospiral BALB/c model from lethality by increasing the survival rate from 25% to 66%. Finally, the biocompatibility of the evaluated anti-MIF compound was explored by cytotoxicity, hemocompatibility, and cell death assay. Ibudilast showed no significant cytotoxicity and hemolytic activity was noticed even at the higher concentration of ≤50 μM and ≥250 μM, when compared with the positive control, 0.1% Triton X-100; no significant cell death was observed at ≤50 μM concentration of Ibudilast in THP-1 cells. From these lines of evidence, we propose that Ibudilast may be a great MIF targeting repurposing drug for reliable supportive treatment of severe leptospirosis.
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Affiliation(s)
- Krishnamoorthi Sumaiya
- Medical Microbiology Laboratory, Department of Microbiology, Centre for Excellence in Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Panneerselvam Selvambika
- Medical Microbiology Laboratory, Department of Microbiology, Centre for Excellence in Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Kalimuthusamy Natarajaseenivasan
- Medical Microbiology Laboratory, Department of Microbiology, Centre for Excellence in Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India.
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Maia MAC, Bettin EB, Barbosa LN, de Oliveira NR, Bunde TT, Pedra ACK, Rosa GA, da Rosa EEB, Seixas Neto ACP, Grassmann AA, McFadden J, Dellagostin OA, McBride AJA. Challenges for the development of a universal vaccine against leptospirosis revealed by the evaluation of 22 vaccine candidates. Front Cell Infect Microbiol 2022; 12:940966. [PMID: 36275031 PMCID: PMC9586249 DOI: 10.3389/fcimb.2022.940966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Leptospirosis is a neglected disease of man and animals that affects nearly half a million people annually and causes considerable economic losses. Current human vaccines are inactivated whole-cell preparations (bacterins) of Leptospira spp. that provide strong homologous protection yet fail to induce a cross-protective immune response. Yearly boosters are required, and serious side-effects are frequently reported so the vaccine is licensed for use in humans in only a handful of countries. Novel universal vaccines require identification of conserved surface-exposed epitopes of leptospiral antigens. Outer membrane β-barrel proteins (βb-OMPs) meet these requirements and have been successfully used as vaccines for other diseases. We report the evaluation of 22 constructs containing protein fragments from 33 leptospiral βb-OMPs, previously identified by reverse and structural vaccinology and cell-surface immunoprecipitation. Three-dimensional structures for each leptospiral βb-OMP were predicted by I-TASSER. The surface-exposed epitopes were predicted using NetMHCII 2.2 and BepiPred 2.0. Recombinant constructs containing regions from one or more βb-OMPs were cloned and expressed in Escherichia coli. IMAC-purified recombinant proteins were adsorbed to an aluminium hydroxide adjuvant to produce the vaccine formulations. Hamsters (4-6 weeks old) were vaccinated with 2 doses containing 50 – 125 μg of recombinant protein, with a 14-day interval between doses. Immunoprotection was evaluated in the hamster model of leptospirosis against a homologous challenge (10 – 20× ED50) with L. interrogans serogroup Icterohaemorrhagiae serovar Copenhageni strain Fiocruz L1-130. Of the vaccine formulations, 20/22 were immunogenic and induced significant humoral immune responses (IgG) prior to challenge. Four constructs induced significant protection (100%, P < 0.001) and sterilizing immunity in two independent experiments, however, this was not reproducible in subsequent evaluations (0 – 33.3% protection, P > 0.05). The lack of reproducibility seen in these challenge experiments and in other reports in the literature, together with the lack of immune correlates and commercially available reagents to characterize the immune response, suggest that the hamster may not be the ideal model for evaluation of leptospirosis vaccines and highlight the need for evaluation of alternative models, such as the mouse.
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Affiliation(s)
- Mara A. C. Maia
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Everton B. Bettin
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Liana N. Barbosa
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Natasha R. de Oliveira
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Tiffany T. Bunde
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Ana Carolina K. Pedra
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Guilherme A. Rosa
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Elias E. B. da Rosa
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Amilton C. P. Seixas Neto
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - André A. Grassmann
- Department of Medicine, University of Connecticut Health, Farmington, CT, United States
| | - Johnjoe McFadden
- School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Odir A. Dellagostin
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Alan J. A. McBride
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
- School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- *Correspondence: Alan J. A. McBride,
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Zhao X, Guo J, Jia X, Yang Y, Liu L, Nie W, Fang Z. Internalization of Leptospira interrogans via diverse endocytosis mechanisms in human macrophages and vascular endothelial cells. PLoS Negl Trop Dis 2022; 16:e0010778. [PMID: 36137081 PMCID: PMC9531806 DOI: 10.1371/journal.pntd.0010778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 10/04/2022] [Accepted: 08/31/2022] [Indexed: 11/18/2022] Open
Abstract
Leptospirosis, one of the leading global causes of morbidity and mortality, is an emerging public health problem, particularly in large urban centers of developing countries. Leptospirosis results from infection with an organism belonging to the Leptospira genus L. interrogans. The extensive invasive ability has previously been documented, however a mechanism that describes how the organism is internalized by human macrophages and transmigrates through human blood vessel remains poorly understood. In the present study, we utilized a human macrophage and vascular endothelial cell line to study the diverse invasive mechanisms by which L. interrogans infections occur. We found that THP-1 and HUVEC had a diverse expression of cell receptors and L. interrogans entered THP-1 and HUVEC by different pathways. In the macrophage model cell line, ITGB1/FAK-signaling mediated microfilament dependent endocytosis with lysosome fusion, whereas ITGB1/CAV-1/PI3K-signaling mediated microfilament dependent endocytosis and transcytosis without lysosome fusion in the endothelial cell model. Shedding of pathogenic leptospires from HUVEC displayed higher viability than those from THP-1. The monolayer of HUVEC maintained integrity during the infection, while 3D imaging showed that leptospires were transmigrated both intra- and intercellularly. These results indicate that endocytosis of leptospires in human macrophages and human vascular endothelial cells are quite different, macrophages are responsible for eliminating leptospires in the human body during the infection while vascular endothelial cells facilitate dissemination of leptospires from blood vessels into target organs where they cause injury. Leptospirosis is a zoonotic bacterial disease which causes 1.03 million cases and 58,900 deaths each year. Human infections occur when the primary reservoir hosts, such as rodents, contaminate food and water with leptospires. Unlike other bacterial pathogens, leptospires invade the human body through mucosal barriers and enter the bloodstream, which can result in septicemia. Left untreated, leptospirosis can spread into multiple organs and tissues such as lungs, liver and kidneys. Pathological features of this disease include high fever, myalgia, lymphadenectasis, hemorrhaging and jaundice. Human macrophages and vascular endothelial cells play important roles in eliminating and preventing the transmission of this pathogen. We speculated that leptospires could be neutralized in macrophages and subsequently transported by vascular endothelial cells throughout the human body. In this research, the diverse mechanisms of human macrophages and vascular endothelial cells infected by leptospires were explored. Our findings can be used to improve the treatment, prevention, and supervision regarding leptospire transmission and infection.
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Affiliation(s)
- Xin Zhao
- Institute of Health Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
- * E-mail: (XZ); (ZF)
| | - Jun Guo
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Quality and Health of Tianjin, Tianjin University of Science & Technology, Tianjin, China
| | - Xiaoyuan Jia
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Yaling Yang
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Quality and Health of Tianjin, Tianjin University of Science & Technology, Tianjin, China
| | - Lijuan Liu
- Institute of Health Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Weizhong Nie
- Department of health quarantine, Qinhuangdao Customs District, Qinhuangdao, China
| | - Zhiqiang Fang
- Institute of Health Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
- * E-mail: (XZ); (ZF)
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Surdel MC, Anderson PN, Hahn BL, Coburn J. Hematogenous dissemination of pathogenic and non-pathogenic Leptospira in a short-term murine model of infection. Front Cell Infect Microbiol 2022; 12:917962. [PMID: 35923802 PMCID: PMC9339599 DOI: 10.3389/fcimb.2022.917962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 06/27/2022] [Indexed: 01/19/2023] Open
Abstract
Leptospirosis is an emerging zoonosis caused by pathogenic Leptospira spp. Because rodents are natural hosts of Leptospira, rodent models of pathogenesis have been limited, but are valuable to understand infection in reservoir animals even in the absence of disease. Mouse models of infection provide advantages due to genetic tractability, so developing murine models of Leptospira infection is crucial for further understanding the biology of this organism. Previously our laboratory developed a short-term murine model of Borrelia burgdorferi hematogenous dissemination to investigate the role of adhesion proteins on bacterial survival and dissemination within a host. Here we adapt this model to Leptospira. C3H/HeJ mice are anesthetized, inoculated intravenously, and then bacteria are allowed to circulate for up to twenty-four hours. Mice are euthanized, perfused with saline, and tissues are harvested for culture and DNA purification. Bacterial burdens are determined by quantitative PCR. Reproducible burdens of bacteria were found in tissues upon inoculation with pathogens and non-pathogens, demonstrating the utility of this model to probe different Leptospira species and strains. Pathogenic L. interrogans has a significantly higher burden in blood, liver, kidney, and bladder at one-hour post-inoculation when compared to non-pathogenic L. biflexa. Colonization of the kidney is essential to the life cycle of pathogenic Leptospira in nature. Measurable burdens of non-pathogenic L. biflexa were found in numerous organs and live leptospires were recovered from blood samples for at least three hours post-inoculation, contrary to the previous belief that non-pathogenic leptospires are rapidly cleared. This short-term murine model of Leptospira hematogenous dissemination will allow for the interrogation of virulence factors potentially important for tissue colonization and evasion of host defenses, and represents a novel animal model for investigating determinants of Leptospira infection.
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Affiliation(s)
- Matthew C. Surdel
- Department of Medicine, Division of Infectious Diseases, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Phillip N. Anderson
- Department of Medicine, Division of Infectious Diseases, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Beth L. Hahn
- Department of Medicine, Division of Infectious Diseases, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Jenifer Coburn
- Department of Medicine, Division of Infectious Diseases, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
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10
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French T, Steffen J, Glas A, Osbelt L, Strowig T, Schott BH, Schüler T, Dunay IR. Persisting Microbiota and Neuronal Imbalance Following T. gondii Infection Reliant on the Infection Route. Front Immunol 2022; 13:920658. [PMID: 35898505 PMCID: PMC9311312 DOI: 10.3389/fimmu.2022.920658] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/25/2022] [Indexed: 12/18/2022] Open
Abstract
Toxoplasma gondii is a highly successful parasite capable of infecting all warm-blooded animals. The natural way of infection in intermediate hosts is the oral ingestion of parasite-contaminated water or food. In murine experimental models, oral infection (p.o.) of mice with T. gondii is applied to investigate mucosal and peripheral immune cell dynamics, whereas intraperitoneal infection (i.p.) is frequently used to study peripheral inflammation as well as immune cell – neuronal interaction in the central nervous system (CNS). However, the two infection routes have not yet been systematically compared along the course of infection. Here, C57BL/6 mice were infected p.o. or i.p. with a low dose of T. gondii cysts, and the acute and chronic stages of infection were compared. A more severe course of infection was detected following i.p. challenge, characterized by an increased weight loss and marked expression of proinflammatory cytokines particularly in the CNS during the chronic stage. The elevated proinflammatory cytokine expression in the ileum was more prominent after p.o. challenge that continued following the acute phase in both i.p. or p.o. infected mice. This resulted in sustained microbial dysbiosis, especially after p.o. challenge, highlighted by increased abundance of pathobionts from the phyla proteobacteria and a reduction of beneficial commensal species. Further, we revealed that in the CNS of i.p. infected mice CD4 and CD8 T cells displayed higher IFNγ production in the chronic stage. This corresponded with an increased expression of C1q and CD68 in the CNS and reduced expression of genes involved in neuronal signal transmission. Neuroinflammation-associated synaptic alterations, especially PSD-95, VGLUT, and EAAT2 expression, were more pronounced in the cortex upon i.p. infection highlighting the profound interplay between peripheral inflammation and CNS homeostasis.
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Affiliation(s)
- Timothy French
- Institute of Inflammation and Neurodegeneration, Health Campus Immunology, Infectiology and Inflammation (GC-I), Otto-von-Guericke University, Magdeburg, Germany
| | - Johannes Steffen
- Institute of Inflammation and Neurodegeneration, Health Campus Immunology, Infectiology and Inflammation (GC-I), Otto-von-Guericke University, Magdeburg, Germany
| | - Albert Glas
- Institute of Inflammation and Neurodegeneration, Health Campus Immunology, Infectiology and Inflammation (GC-I), Otto-von-Guericke University, Magdeburg, Germany
| | - Lisa Osbelt
- Department of Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Till Strowig
- Department of Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Björn H. Schott
- Institute of Inflammation and Neurodegeneration, Health Campus Immunology, Infectiology and Inflammation (GC-I), Otto-von-Guericke University, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Germany
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany
- Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Thomas Schüler
- Institute of Molecular and Clinical Immunology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - Ildiko Rita Dunay
- Institute of Inflammation and Neurodegeneration, Health Campus Immunology, Infectiology and Inflammation (GC-I), Otto-von-Guericke University, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Germany
- *Correspondence: Ildiko Rita Dunay,
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11
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Shetty A, Kundu S, Vernel-Pauillac F, Ratet G, Werts C, Gomes-Solecki M. Transient Presence of Live Leptospira interrogans in Murine Testes. Microbiol Spectr 2022; 10:e0277521. [PMID: 35446113 PMCID: PMC9241917 DOI: 10.1128/spectrum.02775-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 03/25/2022] [Indexed: 01/01/2023] Open
Abstract
Analysis of Leptospira dissemination and colonization of sex organs in rodents is of significant value as it queries the possibility of mammal-to-mammal venereal transmission. The aim of our study was to evaluate the presence and viability of Leptospira interrogans in testes of mice using models of infection that we previously developed. Using sublethal and lethal doses of bioluminescent strains of L. interrogans serovars Manilae and Copenhageni, we visualized the presence of leptospires in testes of C57BL/6 mice as early as 30 min and up to days 3-4 postinfection. This was confirmed by qPCR for the Copenhageni serovar after lethal infection of C3H/HeJ mice. In this model, no histopathological changes were noticed in testis. We further studied persistence of serovar Copenhageni in C3H/HeJ testes after lethal and sublethal infection, with different doses of leptospires. No viable leptospires were recovered from testes of lethally infected mice. However, we found live culturable Leptospira in testes of 19/19 (100%) sublethally infected mice at the acute phase but not at 15 days postinfection, which corresponds to the chronic phase of renal colonization. The data suggest that colonization of testes with live and potentially infectious leptospires is transient and limited to the spirochetemic phase of infection. Further studies are necessary to evaluate if presence of Leptospira in testes of mice leads to excretion in semen and to venereal transmission to female mice. IMPORTANCE Analysis of venereal transmission of Leptospira is important to determine if direct animal to animal transmission occurs, which could impact measures to prevent and treat leptospirosis. The goal of this study was to determine if live Leptospira colonize mouse testes. We found that colonization of mouse testes with live Leptospira was transient and limited to the acute spirochetemic phase of infection and that transient colonization of the testes was insufficient to cause histopathological changes.
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Affiliation(s)
- Advait Shetty
- Department of Pharmaceutical Sciences, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Suman Kundu
- Department of Microbiology, Immunology and Biochemistry, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Frédérique Vernel-Pauillac
- Institut Pasteur, Université de Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la paroi bactérienne, Paris, France
| | - Gwendoline Ratet
- Institut Pasteur, Université de Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la paroi bactérienne, Paris, France
| | - Catherine Werts
- Institut Pasteur, Université de Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la paroi bactérienne, Paris, France
| | - Maria Gomes-Solecki
- Department of Pharmaceutical Sciences, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
- Department of Microbiology, Immunology and Biochemistry, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
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12
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Implication of the IL-10-Expression Signature in the Pathogenicity of Leptospira-Infected Macrophages. Microbiol Spectr 2022; 10:e0259521. [PMID: 35638785 PMCID: PMC9241676 DOI: 10.1128/spectrum.02595-21] [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] [Indexed: 11/20/2022] Open
Abstract
Leptospirosis, an emerging infectious disease caused by pathogenic Leptospira spp., occurs in ecoregions with heavy rainfall and has public health implications. Macrophages are the major anti-Leptospira phagocytes that infiltrate the kidneys during renal leptospirosis, which is caused by leptospires residing in the renal tubules. The pathogenicity of Leptospira spp. in immune effector cells such as macrophages is not well understood. To evaluate this pathogenesis, we characterized and compared the transcriptome-wide alterations in macrophages infected with pathogenic and nonpathogenic Leptospira spp. Using transcriptome data and quantitative reverse transcription PCR analysis, at 2 h postinfection, the hypoxia-inducible factor-1α-dependent glycolysis pathway was implicated in pathogenic Leptospira-infected macrophages but not in nonpathogenic leptospiral infections. Immune-related biological processes were mostly activated in pathogenic Leptospira-infected macrophages, and flow cytometry investigations revealed that classically activated macrophages represent the predominant polarization status. At 24 h after infection, biological pathways associated with interleukin-10, IL-10, signaling the induction of macrophage tolerance, as well as higher levels of IL-10 mRNA and protein expression, were observed in nonpathogenic Leptospira-infected macrophages compared to in pathogenic leptospiral infection. Following leptospiral infection of macrophages, strong IL-10-expressing transcriptome signatures were observed following nonpathogenic leptospiral infection. The transcriptional programs generated in Leptospira-infected macrophages revealed an inflammatory milieu following the production of a critical anti-inflammatory cytokine, IL-10, which is implicated in controlling the pathogenicity of activated macrophages. These findings imply that IL-10-mediated anti-inflammatory responses and tolerance in activated macrophages induced by nonpathogenic Leptospira spp. infection reduce inflammation and tissue damage, thus providing a potential therapeutic target for leptospirosis. IMPORTANCE Activation of macrophages by Leptospira spp. infection is thought to be involved in the pathogenesis of leptospirosis. To evaluate the innate macrophage responses to Leptospira spp., specifically pathogenic versus nonpathogenic Leptospira spp., we characterized the entire transcriptome-wide alterations in infected macrophages. We showed that hypoxia-inducible factor-1α and immune-related pathways are activated in pathogenic leptospiral-infected macrophages. We confirmed the significantly high levels of IL-10-expressing signatures and tolerance in activated macrophages caused by nonpathogenic Leptospira infection. Furthermore, nonpathogenic leptospiral infections attenuated macrophage activation responses. These findings suggest a potential therapeutic strategy for the immune microenvironment caused by macrophage activation driven by IL-10 overexpression, which may contribute to regulating inflammation in leptospirosis.
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13
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Cagliero J, Vernel-Pauillac F, Murray G, Adler B, Matsui M, Werts C. Pathogenic Leptospires Limit Dendritic Cell Activation Through Avoidance of TLR4 and TRIF Signaling. Front Immunol 2022; 13:911778. [PMID: 35812397 PMCID: PMC9258186 DOI: 10.3389/fimmu.2022.911778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 05/26/2022] [Indexed: 11/13/2022] Open
Abstract
Leptospira interrogans is a bacterial species responsible for leptospirosis, a neglected worldwide zoonosis. Mice and rats are resistant and can become asymptomatic carriers, whereas humans and some other mammals may develop severe forms of leptospirosis. Uncommon among spirochetes, leptospires contain lipopolysaccharide (LPS) in their outer membrane. LPS is highly immunogenic and forms the basis for a large number of serovars. Vaccination with inactivated leptospires elicits a protective immunity, restricted to serovars with related LPS. This protection that lasts in mice, is not long lasting in humans and requires annual boosts. Leptospires are stealth pathogens that evade the complement system and some pattern recognition receptors from the Toll-like (TLR) and Nod-Like families, therefore limiting antibacterial defense. In macrophages, leptospires totally escape recognition by human TLR4, and escape the TRIF arm of the mouse TLR4 pathway. However, very little is known about the recognition and processing of leptospires by dendritic cells (DCs), although they are crucial cells linking innate and adaptive immunity. Here we tested the activation of primary DCs derived from human monocytes (MO-DCs) and mouse bone marrow (BM-DCs) 24h after stimulation with saprophytic or different pathogenic virulent or avirulent L. interrogans. We measured by flow cytometry the expression of DC-SIGN, a lectin involved in T-cell activation, co-stimulation molecules and MHC-II markers, and pro- and anti-inflammatory cytokines by ELISA. We found that exposure to leptospires, live or heat-killed, activated dendritic cells. However, pathogenic L. interrogans, especially from the Icterohaemorraghiae Verdun strain, triggered less marker upregulation and less cytokine production than the saprophytic Leptospira biflexa. In addition, we showed a better activation with avirulent leptospires, when compared to the virulent parental strains in murine BM-DCs. We did not observe this difference in human MO-DCs, suggesting a role for TLR4 in DC stimulation. Accordingly, using BM-DCs from transgenic deficient mice, we showed that virulent Icterohaemorraghiae and Manilae serovars dampened DC activation, at least partly, through the TLR4 and TRIF pathways. This work shows a novel bacterial immune evasion mechanism to limit DC activation and further illustrates the role of the leptospiral LPS as a virulence factor.
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Affiliation(s)
- Julie Cagliero
- Institut Pasteur de Nouvelle-Calédonie, member of the Pasteur Network, Immunity and Inflammation Group (GIMIN), Noumea, New Caledonia
- Institut Pasteur, Université de Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi bactérienne, F-75015 Paris, France
- Institut Pasteur de Nouvelle-Calédonie, member of the Pasteur Network, Leptospirosis Research and Expertise Unit, Noumea, New Caledonia
| | - Frédérique Vernel-Pauillac
- Institut Pasteur, Université de Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi bactérienne, F-75015 Paris, France
| | - Gerald Murray
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Ben Adler
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Mariko Matsui
- Institut Pasteur de Nouvelle-Calédonie, member of the Pasteur Network, Immunity and Inflammation Group (GIMIN), Noumea, New Caledonia
| | - Catherine Werts
- Institut Pasteur, Université de Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi bactérienne, F-75015 Paris, France
- *Correspondence: Catherine Werts,
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14
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Kumar A, Varma VP, Faisal SM. Screening of Surface-Exposed Lipoproteins of Leptospira Involved in Modulation of Host Innate Immune Response. Front Microbiol 2022; 13:761670. [PMID: 35401498 PMCID: PMC8988195 DOI: 10.3389/fmicb.2022.761670] [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: 08/20/2021] [Accepted: 02/07/2022] [Indexed: 11/13/2022] Open
Abstract
Leptospira, a zoonotic pathogen, is capable of causing both chronic and acute infection in a susceptible host. Surface-exposed lipoproteins play a major role in modulating the host immune response by activating the innate cells like macrophages and dendritic cells or evading complement attack and killing by phagocytes like neutrophils to favor pathogenesis and establish infection. In this study, we screened some surface-exposed lipoproteins known to be involved in pathogenesis to assess their possible role in immune modulation (innate immune activation or evasion). Surface proteins of the Len family (LenB, LenD, and LenE), Lsa30, Loa22, and Lipl21 were purified in recombinant form and then tested for their ability to activate macrophages of the different host (mouse, human, and bovine). These proteins were tested for binding with complement regulators like Factor H (FH), C4 Binding Protein (C4BP), and host protease Plasminogen (PLG) and also as nucleases to access their possible role in innate immune evasion. Our results show that, of various proteins tested, Loa22 induced strong innate activation and Lsa30 was least stimulatory, as evident from the production of pro-inflammatory cytokines (interleukin-6 and tumor necrosis factor–α) and expression of surface markers [CD80, CD86, and major histocompatibility complex class II (MHCII)]. All the tested proteins were able to bind to FH, C4BP, and PLG; however, Loa22 showed strong binding to PLG correlating to plasmin activity. All the proteins except Loa22 showed nuclease activity, albeit with a requirement of different metal ions. The nuclease activity of these proteins correlated to in vitro degradation of neutrophil extracellular trap (NET). In conclusion, our results indicate that these surface proteins are involved in innate immune modulation and may play a critical role in assisting the bacteria in invading and colonizing the host tissue for persistent infection.
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Affiliation(s)
- Ajay Kumar
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad, India.,Regional Center for Biotechnology, Faridabad, India
| | - Vivek P Varma
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Syed M Faisal
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad, India.,Regional Center for Biotechnology, Faridabad, India
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15
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Kundu S, Shetty A, Gomes-Solecki M. Necroptosis Contributes to Persistent Inflammation During Acute Leptospirosis. Front Immunol 2022; 13:810834. [PMID: 35392072 PMCID: PMC8980737 DOI: 10.3389/fimmu.2022.810834] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 03/01/2022] [Indexed: 12/21/2022] Open
Abstract
Leptospirosis is an emerging infectious disease. Recently, canine and human leptospirosis outbreaks were reported in California and New York, respectively. In this study we evaluated the role that cell death processes play in the inflammatory response to Leptospira. Groups of male C3H/HeJ mice were infected with pathogenic L. interrogans and non-pathogenic L. biflexa for 24 and 72 hours; inflammatory processes were characterized for apoptosis and necroptosis by flowcytometry of spleen cells and were further assessed for expression of biomarkers of necroptosis by western blot. We found that pathogenic L. interrogans promotes apoptosis in myeloid neutrophils and monocytes at 24h and 72h post-infection, whereas L. biflexa promotes apoptosis of myeloid monocytes only at 24h post-infection. It is interesting that the immune cells undergoing the common programmed cell death pathway (apoptosis) are the cell types which were not increased in frequency in spleen of mice infected with L. interrogans (neutrophils) and L. biflexa (monocytes) in our previous study. The same trend was observed with pathogenic L. interrogans inducing necroptosis of myeloid neutrophils in addition to monocytes and macrophages at 24h and/or 72h post-infection, whereas L. biflexa promoted this pro-inflammatory cell death process in monocytes and macrophages only at 24h post-infection. Thus, early apoptosis and necroptosis of these cell types may explain its absence in frequency in spleen. Furthermore, at 24h and 72h, expression of the necroptosis molecular biomarkers p-MLKL, p-RIP1 and p-RIP3 was increased post infection with pathogenic L. interrogans. These data suggest that the underlying cell death processes involved in immune responses to pathogenic Leptospira contribute directly to persistent inflammation during the early stages of leptospirosis.
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Affiliation(s)
- Suman Kundu
- Department of Microbiology, Immunology and Biochemistry, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Advait Shetty
- Department of Pharmaceutical Sciences, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Maria Gomes-Solecki
- Department of Microbiology, Immunology and Biochemistry, The University of Tennessee Health Science Center, Memphis, TN, United States,Department of Pharmaceutical Sciences, The University of Tennessee Health Science Center, Memphis, TN, United States,*Correspondence: Maria Gomes-Solecki,
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