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Ruiz-Pacheco JA, Reyes-Martínez JE, Gómez-Navarro B, Castillo-Díaz LA, Portilla de Buen E. Leptospirosis: A dual threat - predisposing risk for renal transplant and trigger for renal transplant dysfunction. Hum Immunol 2024; 85:110835. [PMID: 38972268 DOI: 10.1016/j.humimm.2024.110835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 05/29/2024] [Accepted: 06/24/2024] [Indexed: 07/09/2024]
Abstract
Leptospirosis (LTPS) is a bacterial infection that affects humans, often with mild or no symptoms. It is estimated that approximately 10 % of patients with LTPS may experience multi-organ dysfunction, including renal abnormalities. In regions where LTPS is widespread, a considerable number of instances involving acute kidney injury (AKI) and chronic kidney disease (CKD) of unknown etiology (CKDu) have been reported. Additionally, studies have shown a correlation between kidney graft dysfunction in patients with stable kidney transplants after LTPS. These findings indicate that exposure to LTPS may increase the likelihood of kidney transplantation due to the onset of both acute and chronic kidney injuries. Simultaneously, it poses a potential risk to the stability of kidney grafts. Unfortunately, there is limited scientific literature addressing this issue, making it difficult to determine the negative impact that LTPS may have, such as its role as a risk factor for the need of kidney transplantation or as a threat to individuals who have undergone kidney transplants. This study aims to shed light on the immune mechanisms triggered during LTPS infection and their importance in both kidney damage and allograft dysfunction.
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Affiliation(s)
- Juan Alberto Ruiz-Pacheco
- Investigador por México-CONAHCYT, División de Investigación Quirúrgica, Centro de Investigación Biomédica de Occidente, IMSS, Guadalajara, Jalisco, Mexico.
| | | | - Benjamín Gómez-Navarro
- Servicio de Nefrología y trasplantes, Hospital Country 2000, Guadalajara, Jalisco, Mexico
| | - Luis Alberto Castillo-Díaz
- Departamento de Medicina y Ciencias de la Salud, Facultad Interdiciplinaria de Ciencias Biólogicas y de la Salud, Universidad de Sonora, Hermosillo, Mexico
| | - Eliseo Portilla de Buen
- Laboratorio de Investigación quirúrgica, Centro de Investigación Biomédica de Occidente, IMSS, Guadalajara, Jalisco, Mexico
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Krangvichian P, Nakornpakdee Y, Sangjun N, Komanee P, Techawiwattanaboon T, Patarakul K. Sublethal infection of C3H/HeNJ against Leptospira interrogans serovar Pomona. Acta Trop 2023; 238:106701. [PMID: 36216095 DOI: 10.1016/j.actatropica.2022.106701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 08/15/2022] [Accepted: 09/27/2022] [Indexed: 01/11/2023]
Abstract
Leptospirosis is a worldwide zoonotic disease caused by pathogenic Leptospira spp. Leptospires can infect a variety of mammalian species. Golden Syrian hamsters are mostly used to study acute leptospirosis. However, the immunopathogenic mechanism is poorly understood because immunological reagents for hamsters are limited. This study aimed to establish C3H/HeNJ mice as an animal model for leptospirosis. Five-week-old C3H/HeNJ mice were infected with either low (103 cells) or high (106 cells) inoculum dose of Leptospira interrogans serovar Pomona. All mice were investigated for survival rate, leptospiral load and histopathology of target organs, antibody levels, and cytokine production (IFN-γ, IL-6 and IL-10) at day 28 post-infection. All infected mice survived and did not develop acute lethal infection. However, C3H/HeNJ mice infected with 106 cells of leptospires showed kidney colonization of leptospires and pathological changes in the lung and kidney including renal fibrosis. The glomerular size in PAS-D stained kidney tissues of C3H/HeNJ mice infected with 106 cells of leptospires was significantly reduced compared to that of mice infected with 103 cells of leptospires and non-infected mice. High-dose leptospires induced significantly greater levels of IFN-gamma and IL-6 than low-dose leptospires, but IL-10 level was not significantly different. Moreover, 106 leptospiral cells induced predominant IgG2a isotype suggesting Th1-like response. These results suggest that C3H/HeNJ mice may be used as a sublethal model of leptospirosis.
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Affiliation(s)
- Pratomporn Krangvichian
- Medical Microbiology, Interdisciplinary Program, Graduate School, Chulalongkorn University, Pathumwan, Bangkok, 10330 Thailand; Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Pathumwan, Bangkok, 10330 Thailand
| | - Yaowarin Nakornpakdee
- Department of Pathobiology, Faculty of Science, Mahidol University, Ratchathewi, Bangkok, 10400 Thailand
| | - Noppadon Sangjun
- Armed Force Research Institute of Medical Sciences (AFRIMS), Ratchathewi, Bangkok, 10400 Thailand
| | - Pat Komanee
- Armed Force Research Institute of Medical Sciences (AFRIMS), Ratchathewi, Bangkok, 10400 Thailand
| | - Teerasit Techawiwattanaboon
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Pathumwan, Bangkok, 10330 Thailand; Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Pathumwan, Bangkok, 10330 Thailand
| | - Kanitha Patarakul
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Pathumwan, Bangkok, 10330 Thailand; Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Pathumwan, Bangkok, 10330 Thailand.
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Vittal R, Fisher AJ, Thompson EL, Cipolla EM, Gu H, Mickler EA, Varre A, Agarwal M, Kim KK, Vasko MR, Moore BB, Lama VN. Overexpression of Decay Accelerating Factor Mitigates Fibrotic Responses to Lung Injury. Am J Respir Cell Mol Biol 2022; 67:459-470. [PMID: 35895592 PMCID: PMC9564933 DOI: 10.1165/rcmb.2021-0463oc] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
CD55 or decay accelerating factor (DAF), a ubiquitously expressed glycosylphosphatidylinositol (GPI)-anchored protein, confers a protective threshold against complement dysregulation which is linked to the pathogenesis of idiopathic pulmonary fibrosis (IPF). Since lung fibrosis is associated with downregulation of DAF, we hypothesize that overexpression of DAF in fibrosed lungs will limit fibrotic injury by restraining complement dysregulation. Normal primary human alveolar type II epithelial cells (AECs) exposed to exogenous complement 3a or 5a, and primary AECs purified from IPF lungs demonstrated decreased membrane-bound DAF expression with concurrent increase in the endoplasmic reticulum (ER) stress protein, ATF6. Increased loss of extracellular cleaved DAF fragments was detected in normal human AECs exposed to complement 3a or 5a, and in lungs of IPF patients. C3a-induced ATF6 expression and DAF loss was inhibited using pertussis toxin (an enzymatic inactivator of G-protein coupled receptors), in murine AECs. Treatment with soluble DAF abrogated tunicamycin-induced C3a secretion and ER stress (ATF6 and BiP expression) and restored epithelial cadherin. Bleomycin-injured fibrotic mice subjected to lentiviral overexpression of DAF demonstrated diminished levels of local collagen deposition and complement activation. Further analyses showed diminished release of DAF fragments, as well as reduction in apoptosis (TUNEL and caspase 3/7 activity), and ER stress-related transcripts. Loss-of-function studies using Daf1 siRNA demonstrated worsened lung fibrosis detected by higher mRNA levels of Col1a1 and epithelial injury-related Muc1 and Snai1, with exacerbated local deposition of C5b-9. Our studies provide a rationale for rescuing fibrotic lungs via DAF induction that will restrain complement dysregulation and lung injury.
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Affiliation(s)
- Ragini Vittal
- Division of Pulmonary and Critical Care, Department of Internal Medicine and
| | - Amanda J. Fisher
- Division of Pulmonary and Critical Care, Department of Medicine and
| | - Eric L. Thompson
- Department of Pharmacology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Ellyse M. Cipolla
- Division of Pulmonary and Critical Care, Department of Internal Medicine and
| | - Hongmei Gu
- Division of Pulmonary and Critical Care, Department of Medicine and
| | | | - Ananya Varre
- Division of Pulmonary and Critical Care, Department of Internal Medicine and
| | - Manisha Agarwal
- Division of Pulmonary and Critical Care, Department of Internal Medicine and
| | - Kevin K. Kim
- Division of Pulmonary and Critical Care, Department of Internal Medicine and
| | - Michael R. Vasko
- Department of Pharmacology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Bethany B. Moore
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan; and
| | - Vibha N. Lama
- Division of Pulmonary and Critical Care, Department of Internal Medicine and
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Going Micro in Leptospirosis Kidney Disease. Cells 2022; 11:cells11040698. [PMID: 35203344 PMCID: PMC8869946 DOI: 10.3390/cells11040698] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 02/13/2022] [Accepted: 02/14/2022] [Indexed: 02/05/2023] Open
Abstract
Leptospirosis is a zoonotic and waterborne disease worldwide. It is a neglected infectious disease caused by Leptospira spp., as well as a reemerging disease and global public health problem with respect to morbidity and mortality both in humans and animals. Leptospirosis emerges as a leading cause of acute febrile illness along with hepatorenal injury in many countries, including Thailand. While most affected persons are symptomatic in acute disease, which is always difficult to differentiate from other tropical diseases, there is growing evidence of subtle manifestations that cause unrecognized chronic symptoms. The kidney is one of the common organs affected by Leptospires. Although acute kidney injury in the spectrum of interstitial nephritis is a well-described characteristic in severe leptospirosis, chronic kidney disease from leptospirosis is widely discussed. Early recognition of severe leptospirosis leads to reduce morbidity and mortality. Thus, in this review, we highlight the spectrum of characteristics involved in leptospirosis kidney disease and the use of serologic and molecular methods, as well as the treatments of severe leptospirosis.
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Prado LG, Barbosa AS. Understanding the Renal Fibrotic Process in Leptospirosis. Int J Mol Sci 2021; 22:ijms221910779. [PMID: 34639117 PMCID: PMC8509513 DOI: 10.3390/ijms221910779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/29/2021] [Accepted: 10/02/2021] [Indexed: 12/12/2022] Open
Abstract
Leptospirosis is a neglected infectious disease caused by pathogenic species of the genus Leptospira. The acute disease is well-described, and, although it resembles other tropical diseases, it can be diagnosed through the use of serological and molecular methods. While the chronic renal disease, carrier state, and kidney fibrosis due to Leptospira infection in humans have been the subject of discussion by researchers, the mechanisms involved in these processes are still overlooked, and relatively little is known about the establishment and maintenance of the chronic status underlying this infectious disease. In this review, we highlight recent findings regarding the cellular communication pathways involved in the renal fibrotic process, as well as the relationship between renal fibrosis due to leptospirosis and CKD/CKDu.
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Affiliation(s)
- Luan Gavião Prado
- Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo 05503-900, Brazil;
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Lineu Prestes 1374, São Paulo 05508-000, Brazil
| | - Angela Silva Barbosa
- Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo 05503-900, Brazil;
- Correspondence:
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Chou LF, Chen TW, Yang HY, Tian YC, Chang MY, Hung CC, Hsu SH, Tsai CY, Ko YC, Yang CW. Transcriptomic signatures of exacerbated progression in leptospirosis subclinical chronic kidney disease with secondary nephrotoxic injury. Am J Physiol Renal Physiol 2021; 320:F1001-F1018. [PMID: 33779314 DOI: 10.1152/ajprenal.00640.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
High-incidence regions of leptospirosis caused by Leptospira spp. coincide with chronic kidney disease. This study investigated whether asymptomatic leptospirosis is an emerging culprit that predisposes to progressive chronic kidney disease when superimposed on secondary nephrotoxic injury. Kidney histology/function and whole transcriptomic profiles were evaluated for Leptospira-infected C57/BL6 mice with adenine-induced kidney injury. The extent of tubulointerstitial kidney lesions and expression of inflammation/fibrosis genes in infected mice with low-dose (0.1%) adenine, particularly in high-dose (0.2%) adenine-fed superimposed on Leptospira-infected mice, were significantly increased compared with mice following infection or adenine diet alone, and the findings are consistent with renal transcriptome analysis. Pathway enrichment findings showed that integrin-β- and fibronectin-encoding genes had distinct expression within the integrin-linked kinase-signaling pathway, which were upregulated in 0.2% adenine-fed Leptospira-infected mice but not in 0.2% adenine-fed mice, indicating that background subclinical Leptospiral infection indeed enhanced subsequent secondary nephrotoxic kidney injury and potential pathogenic molecules associated with secondary nephrotoxic leptospirosis. Comparative analysis of gene expression patterns with unilateral ureteric obstruction-induced mouse renal fibrosis and patients with chronic kidney disease showed that differentially expressed orthologous genes such as hemoglobin-α2, PDZ-binding kinase, and DNA topoisomerase II-α were identified in infected mice fed with low-dose and high-dose adenine, respectively, revealing differentially expressed signatures identical to those found in the datasets and may serve as markers of aggravated kidney progression. This study indicates that background subclinical leptospirosis, when subjected to various degrees of subsequent secondary nephrotoxic injury, may predispose to exacerbated fibrosis, mimicking the pathophysiological process of progressive chronic kidney disease.NEW & NOTEWORTHY Leptospira-infected mice followed by secondary nephrotoxic injury exacerbated immune/inflammatory responses and renal fibrosis. Comparison with the murine model revealed candidates involved in the progression of renal fibrosis in chronic kidney disease (CKD). Comparative transcriptome study suggests that secondary nephrotoxic injury in Leptospira-infected mice recapitulates the gene expression signatures found in CKD patients. This study indicates that secondary nephrotoxic injury may exacerbate CKD in chronic Leptospira infection implicating in the progression of CKD of unknown etiology.
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Affiliation(s)
- Li-Fang Chou
- Kidney Research Center and Department of Nephrology, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Ting-Wen Chen
- Institute of Bioinformatics and Systems Biology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan.,Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan.,Center for Intelligent Drug Systems and Smart Bio-devices (IDS2B), National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| | - Huang-Yu Yang
- Kidney Research Center and Department of Nephrology, Chang Gung Memorial Hospital, Linkou, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ya-Chung Tian
- Kidney Research Center and Department of Nephrology, Chang Gung Memorial Hospital, Linkou, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ming-Yang Chang
- Kidney Research Center and Department of Nephrology, Chang Gung Memorial Hospital, Linkou, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Cheng-Chieh Hung
- Kidney Research Center and Department of Nephrology, Chang Gung Memorial Hospital, Linkou, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Shen-Hsing Hsu
- Kidney Research Center and Department of Nephrology, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Chung-Ying Tsai
- Kidney Research Center and Department of Nephrology, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Yi-Ching Ko
- Kidney Research Center and Department of Nephrology, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Chih-Wei Yang
- Kidney Research Center and Department of Nephrology, Chang Gung Memorial Hospital, Linkou, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
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Anti-Leptospira immunoglobulin profiling in mice reveals strain specific IgG and persistent IgM responses associated with virulence and renal colonization. PLoS Negl Trop Dis 2021; 15:e0008970. [PMID: 33705392 PMCID: PMC8007020 DOI: 10.1371/journal.pntd.0008970] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/29/2021] [Accepted: 02/23/2021] [Indexed: 12/14/2022] Open
Abstract
Leptospira interrogans is a pathogenic spirochete responsible for leptospirosis, a neglected, zoonotic reemerging disease. Humans are sensitive hosts and may develop severe disease. Some animal species, such as rats and mice can become asymptomatic renal carriers. More than 350 leptospiral serovars have been identified, classified on the basis of the antibody response directed against the lipopolysaccharide (LPS). Similarly to whole inactivated bacteria used as human vaccines, this response is believed to confer only short-term, serogroup-specific protection. The immune response of hosts against leptospires has not been thoroughly studied, which complicates the testing of vaccine candidates. In this work, we studied the immunoglobulin (Ig) profiles in mice infected with L. interrogans over time to determine whether this humoral response confers long-term protection after homologous challenge six months post-infection. Groups of mice were injected intraperitoneally with 2×107 leptospires of one of three pathogenic serovars (Manilae, Copenhageni or Icterohaemorrhagiae), attenuated mutants or heat-killed bacteria. Leptospira-specific immunoglobulin (IgA, IgM, IgG and 4 subclasses) produced in the first weeks up to 6 months post-infection were measured by ELISA. Strikingly, we found sustained high levels of IgM in mice infected with the pathogenic Manilae and Copenhageni strains, both colonizing the kidney. In contrast, the Icterohaemorrhagiae strain did not lead to kidney colonization, even at high dose, and triggered a classical IgM response that peaked at day 8 post-infection and disappeared. The virulent Manilae and Copenhageni serovars elicited high levels and similar profiles of IgG subclasses in contrast to Icterohaemorrhagiae strains that stimulated weaker antibody responses. Inactivated heat-killed Manilae strains elicited very low responses. However, all mice pre-injected with leptospires challenged with high doses of homologous bacteria did not develop acute leptospirosis, and all antibody responses were boosted after challenge. Furthermore, we showed that 2 months post-challenge, mice pre-infected with the attenuated M895 Manilae LPS mutant or heat-killed bacterin were completely protected against renal colonization. In conclusion, we observed a sustained IgM response potentially associated with chronic leptospiral renal infection. We also demonstrated in mice different profiles of protective and cross-reactive antibodies after L. interrogans infection, depending on the serovar and virulence of strains. Leptospira interrogans is a pathogenic spirochete responsible for leptospirosis, a neglected zoonotic reemerging disease. The immune response of hosts against these bacteria has not been thoroughly studied. Here, we studied over 6 months the antibody profiles in mice infected with L. interrogans and determined whether this humoral response confers long-term protection after homologous challenge six months after primary infection. Groups of mice were infected intraperitoneally with 2×107 bacteria of one of three different pathogenic serovars (Manilae, Copenhageni and Icterohaemorrhagiae) and some corresponding attenuated avirulent mutants. We measured by ELISA each type of Leptospira-specific immunoglobulin (Ig) (IgA, IgM, IgG and 4 subclasses) produced in the first weeks up to 6 months post-infection and studied their cross-reactivities among serovars. We showed different profiles of antibody response after L. interrogans challenge in mice, depending on the serovar and virulence of strains. However, all infected mice, including the ones harboring low antibody levels, like mice vaccinated with an inactivated, heat-killed strain, were protected against leptospirosis after challenge. Notably, we also showed an unusual sustained IgM response associated with chronic leptospiral colonization. Altogether, this long-term immune protection is different from what is known in humans and warrants further investigation.
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Nair N, Gomes-Solecki M. A Mouse Model of Sublethal Leptospirosis: Protocols for Infection with Leptospira Through Natural Transmission Routes, for Monitoring Clinical and Molecular Scores of Disease, and for Evaluation of the Host Immune Response. CURRENT PROTOCOLS IN MICROBIOLOGY 2020; 59:e127. [PMID: 33141517 PMCID: PMC7643393 DOI: 10.1002/cpmc.127] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Leptospirosis is a zoonotic disease caused by pathogenic Leptospira species that are maintained in sylvatic and domestic environments by transmission among rodents and other carriers. Humans become infected after contact of breached skin or mucosa with contaminated water or soil. Understanding persistent or sublethal infection in a host is critical for controlling human risk of exposure to pathogenic Leptospira. Animal models that recapitulate disease progression after infection via natural transmission routes are more appropriate for validation of vaccines and therapeutics. Furthermore, the ability to measure shedding of live Leptospira in urine of reservoir and carrier hosts can be used to develop new diagnostic assays and sensors to evaluate human risk of exposure. We developed inbred mouse models of Leptospirosis, that bypass survival as a criterion, in which we can analyze both pathogen and host factors affecting sublethal infection (<1 month), including shedding of Leptospira in urine. Mice are infected with pathogenic Leptospira using a physiologic route, and the clinical, histological, and molecular scores of disease are measured. Furthermore, the host immune response to Leptospira is evaluated. This mouse model also provides a tool in which to test fundamental hypotheses related to host-pathogen interactions and the immune mechanisms engaged in protective and pathogenic immune responses. © 2020 Wiley Periodicals LLC Basic Protocol 1: Culture and maintenance of virulent Leptospira Basic Protocol 2: Infection of mice through a physiologic route and collection of clinical scores and biological samples Basic Protocol 3: Analysis of pathogenesis after Leptospira infection.
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Affiliation(s)
- Nisha Nair
- Department of Microbiology, Immunology and Biochemistry, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Maria Gomes-Solecki
- Department of Microbiology, Immunology and Biochemistry, The University of Tennessee Health Science Center, Memphis, TN, USA
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Plasma Osteopontin Levels is Associated with Biochemical Markers of Kidney Injury in Patients with Leptospirosis. Diagnostics (Basel) 2020; 10:diagnostics10070439. [PMID: 32610429 PMCID: PMC7399986 DOI: 10.3390/diagnostics10070439] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/20/2020] [Accepted: 06/25/2020] [Indexed: 12/11/2022] Open
Abstract
Leptospirosis becomes severe, with a fatality rate of >10%, and manifests as severe lung injury accompanied by acute kidney injury. Using urine and blood samples of 112 patients with leptospirosis, osteopontin (OPN), galectin-9 (Gal-9) and other kidney-related biomarkers were measured to understand the pathological and diagnostic roles of OPN and Gal-9 in leptospirosis. Plasma levels of full-length (FL)-OPN (pFL-OPN) (p < 0.0001), pFL-Gal-9(p < 0.0001) and thrombin-cleaved OPN (p < 0.01) were significantly higher in patients with leptospirosis than in healthy controls (n = 30), as were levels of several indicators of renal toxicity: serum cystatin C (p < 0.0001), urine N-acetyl-β-glucosaminidase (NAG)/creatinine (p < 0.05), and urine clusterin/creatinine (p < 0.05). pFL-Gal-9 levels were negatively correlated with pFL-OPN levels (r = −0.24, p < 0.05). pFL-OPN levels were positively correlated with serum cystatin C (r = 0.41, p < 0.0001), urine NAG/creatinine (r = 0.35, p < 0.001), urine clusterin/creatinine (r = 0.33, p < 0.01), and urine cystatin C/creatinine (r = 0.33, p < 0.05) levels. In a group of patients with abnormally high creatinine levels, significantly higher levels of serum cystatin C (p < 0.0001) and pFL-OPN (p < 0.001) were observed. Our results demonstrate that pFL-OPN reflect kidney injury among patients with leptospirosis.
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10
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Barbosa AS, Isaac L. Strategies used by Leptospira spirochetes to evade the host complement system. FEBS Lett 2020; 594:2633-2644. [PMID: 32153015 DOI: 10.1002/1873-3468.13768] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 12/19/2022]
Abstract
Leptospires are highly invasive spirochetes equipped with efficient strategies for dissemination in the host. The Leptospira genus currently comprises 64 species divided into two major clades: the saprophytes composed of nonpathogenic, free-living organisms, and the pathogens encompassing all the species that cause mild or severe infections in humans and animals. While saprophytes are highly susceptible to the lytic action of the complement system, pathogenic (virulent) strains have evolved virulence strategies that allow efficient colonization of a variety of hosts and target organs, including mechanisms to circumvent hosts' innate and acquired immune responses. Pathogenic Leptospira avoid complement-mediated killing by recruiting host complement regulatory proteins and by targeting complement proteins using own and host-expressed proteases. This review outlines the role of complement in eradicating saprophytic Leptospira and the stratagems adopted by pathogenic Leptospira to maneuver the host complement system for their benefit.
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Affiliation(s)
| | - Lourdes Isaac
- Laboratory of Complement, Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, Brazil
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11
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Cytokine Profile in Early Infection by Leptospira interrogans in A/J Mice. J Immunol Res 2019; 2019:1892508. [PMID: 31687410 PMCID: PMC6800925 DOI: 10.1155/2019/1892508] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 04/07/2019] [Accepted: 06/22/2019] [Indexed: 12/28/2022] Open
Abstract
Leptospirosis is considered a neglected disease with an estimated more than one million cases every year. Since rodents are at the same time the main reservoir and generally asymptomatic to Leptospira infection, understanding why some animal species are resistant and others are susceptible to this infection would shed some light in how to control this important zoonosis. The innate immune response against Leptospira is mainly dependent on phagocytosis and activation of the Complement System. In this context, cytokines may drive the early control of infection and the adaptive response. Since the Complement System is important to eliminate leptospires in vivo, we investigated if Complement C5 in A/J mice would modulate the cytokine production during infection by Leptospira interrogans serovar Kennewicki type Pomona Fromm (LPF). Thus, our aim was to investigate the systemic levels of pro- and anti-inflammatory cytokines during Leptospira infection in the blood, liver, lung, and kidney on the third and sixth days of infection in A/J C5+/+ and A/J C5-/- mice. Blood levels of TNF-α, IL-6, IFN-γ, and MCP-1 reached a peak on the third day. Although both mouse strains developed splenomegaly, similar histopathological alterations in the liver and the lung, levels of pro- and anti-inflammatory cytokines were different. A/J C5+/+ mice had higher levels of liver IL-10, IL-1β, IL-12p40, and IL-12p70 and kidney IL-1β, IL-12p40, and IL-12p70 on the sixth day of infection when compared to A/J C5-/- mice. Our results showed that in A/J genetic background, the Complement component C5 modulates a cytokine profile in the liver and kidney of infected mice, which may play a role in the control of disease progression.
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12
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Chou LF, Chen TW, Yang HY, Chang MY, Hsu SH, Tsai CY, Ko YC, Huang CT, Tian YC, Hung CC, Yang CW. Murine Renal Transcriptome Profiles Upon Leptospiral Infection: Implications for Chronic Kidney Diseases. J Infect Dis 2019; 218:1411-1423. [PMID: 29868892 DOI: 10.1093/infdis/jiy339] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/01/2018] [Indexed: 01/21/2023] Open
Abstract
Background Leptospirosis caused by pathogenic Leptospira spp leads to kidney damage that may progress to chronic kidney disease. However, how leptospiral infections induced renal damage is unclear. Methods We apply microarray and next-generation sequencing technologies to investigate the first murine transcriptome-wide, leptospires-mediated changes in renal gene expression to identify biological pathways associated with kidney damage. Results Leptospiral genes were detected in renal transcriptomes of mice infected with Leptospira interrogans at day 28 postinfection, suggesting colonization of leptospires within the kidney with propensity of chronicity. Comparative differential gene expression and pathway analysis were investigated in renal transcriptomes of mice infected with pathogens and nonpathogens. Pathways analysis showed that Toll-like receptor signaling, complements activation, T-helper 1 type immune response, and T cell-mediated immunity/chemotaxis/proliferation were strongly associated with progressive tubulointerstitial damage caused by pathogenic leptospiral infection. In addition, 26 genes related with complement system, immune function, and cell-cell interactions were found to be significantly up-regulated in the L interrogans-infected renal transcriptome. Conclusions Our results provided comprehensive knowledge regarding the host transcriptional response to leptospiral infection in murine kidneys, particularly the involvement of cell-to-cell interaction in the immune response. It would provide valuable resources to explore functional studies of chronic renal damage caused by leptospiral infection.
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Affiliation(s)
- Li-Fang Chou
- Kidney Research Center, Chang Gung Memorial Hospital, Linkou
| | - Ting-Wen Chen
- Molecular Medicine Research Center, Chang Gung University, Taoyuan.,Department of Otolaryngology-Head and Neck Surgery, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Huang-Yu Yang
- Kidney Research Center, Chang Gung Memorial Hospital, Linkou.,College of Medicine, Chang Gung University, Taoyuan
| | - Ming-Yang Chang
- Kidney Research Center, Chang Gung Memorial Hospital, Linkou.,College of Medicine, Chang Gung University, Taoyuan
| | - Shen-Hsing Hsu
- Kidney Research Center, Chang Gung Memorial Hospital, Linkou
| | - Chung-Ying Tsai
- Kidney Research Center, Chang Gung Memorial Hospital, Linkou
| | - Yi-Ching Ko
- Kidney Research Center, Chang Gung Memorial Hospital, Linkou
| | | | - Ya-Chung Tian
- Kidney Research Center, Chang Gung Memorial Hospital, Linkou.,College of Medicine, Chang Gung University, Taoyuan
| | - Cheng-Chieh Hung
- Kidney Research Center, Chang Gung Memorial Hospital, Linkou.,College of Medicine, Chang Gung University, Taoyuan
| | - Chih-Wei Yang
- Kidney Research Center, Chang Gung Memorial Hospital, Linkou.,College of Medicine, Chang Gung University, Taoyuan
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13
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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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14
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Cagliero J, Villanueva SYAM, Matsui M. Leptospirosis Pathophysiology: Into the Storm of Cytokines. Front Cell Infect Microbiol 2018; 8:204. [PMID: 29974037 PMCID: PMC6019470 DOI: 10.3389/fcimb.2018.00204] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/31/2018] [Indexed: 12/20/2022] Open
Abstract
Leptospirosis is a neglected tropical zoonosis caused by pathogenic spirochetes of the genus Leptospira. Infected reservoir animals, typically mice and rats, are asymptomatic, carry the pathogen in their renal tubules, and shed pathogenic spirochetes in their urine, contaminating the environment. Humans are accidental hosts of pathogenic Leptospira. Most human infections are mild or asymptomatic. However, 10% of human leptospirosis cases develop into severe forms, including high leptospiremia, multi-organ injuries, and a dramatically increased mortality rate, which can relate to a sepsis-like phenotype. During infection, the triggering of the inflammatory response, especially through the production of cytokines, is essential for the early elimination of pathogens. However, uncontrolled cytokine production can result in a cytokine storm process, followed by a state of immunoparalysis, which can lead to sepsis and associated organ failures. In this review, the involvement of cytokine storm and subsequent immunoparalysis in the development of severe leptospirosis in susceptible hosts will be discussed. The potential contribution of major pro-inflammatory cytokines in the development of tissue lesions and systemic inflammatory response, as well as the role of anti-inflammatory cytokines in contributing to the onset of a deleterious immunosuppressive cascade will also be examined. Data from studies comparing susceptible and resistant mouse models will be included. Lastly, a concise discussion on the use of cytokines for therapeutic purposes or as biomarkers of leptospirosis severity will be provided.
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Affiliation(s)
- Julie Cagliero
- Group Immunity and Inflammation, Institut Pasteur International Network, Institut Pasteur in New Caledonia, Nouméa, New Caledonia
| | - Sharon Y A M Villanueva
- Department of Medical Microbiology, College of Public Health, University of the Philippines, Manila, Philippines
| | - Mariko Matsui
- Group Immunity and Inflammation, Institut Pasteur International Network, Institut Pasteur in New Caledonia, Nouméa, New Caledonia
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15
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de Castro ÍA, Bavia L, Fraga TR, Amano MT, Breda LCD, Granados-Martinez AP, da Silva AMG, Vasconcellos SA, Isaac L. Role of Murine Complement Component C5 in Acute in Vivo Infection by Pathogenic Leptospira interrogans. Front Cell Infect Microbiol 2018; 8:63. [PMID: 29568732 PMCID: PMC5852101 DOI: 10.3389/fcimb.2018.00063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 02/13/2018] [Indexed: 01/07/2023] Open
Abstract
Leptospirosis is considered one of the most important zoonosis worldwide. The activation of the Complement System is important to control dissemination of several pathogens in the host. Only a few studies have employed murine models to investigate leptospiral infection and our aim in this work was to investigate the role of murine C5 during in vivo infection, comparing wild type C57BL/6 (B6 C5+/+) and congenic C57BL/6 (B6 C5−/−, C5 deficient) mice during the first days of infection. All animals from both groups survived for at least 8 days post-infection with pathogenic Leptospira interrogans serovar Kennewicki strain Fromm (LPF). At the third day of infection, we observed greater numbers of LPF in the liver of B6 C5−/− mice when compared to B6 C5+/+ mice. Later, on the sixth day of infection, the LPF population fell to undetectable levels in the livers of both groups of mice. On the third day, the inflammatory score was higher in the liver of B6 C5+/+ mice than in B6 C5−/− mice, and returned to normal on the sixth day of infection in both groups. No significant histopathological differences were observed in the lung, kidney and spleen from both infected B6 C5+/+ than B6 C5−/− mice. Likewise, the total number of circulating leukocytes was not affected by the absence of C5. The liver levels of IL-10 on the sixth day of infection was lower in the absence of C5 when compared to wild type mice. No significant differences were observed in the levels of several inflammatory cytokines when B6 C5+/+ and B6 C5−/− were compared. In conclusion, C5 may contribute to the direct killing of LPF in the first days of infection in C57BL/6 mice. On the other hand, other effector immune mechanisms probably compensate Complement impairment since the mice survival was not affected by the absence of C5 and its activated fragments, at least in the early stage of this infection.
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Affiliation(s)
- Íris A de Castro
- Laboratory of Complement, Department of Immunology, University of São Paulo, São Paulo, Brazil
| | - Lorena Bavia
- Laboratory of Complement, Department of Immunology, University of São Paulo, São Paulo, Brazil
| | - Tatiana R Fraga
- Laboratory of Complement, Department of Immunology, University of São Paulo, São Paulo, Brazil
| | - Mariane T Amano
- Laboratory of Complement, Department of Immunology, University of São Paulo, São Paulo, Brazil
| | - Leandro C D Breda
- Laboratory of Complement, Department of Immunology, University of São Paulo, São Paulo, Brazil
| | | | - Ana M G da Silva
- Institute of Tropical Medicine, University of São Paulo, São Paulo, Brazil
| | | | - Lourdes Isaac
- Laboratory of Complement, Department of Immunology, University of São Paulo, São Paulo, Brazil
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16
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Potula HH, Richer L, Werts C, Gomes-Solecki M. Pre-treatment with Lactobacillus plantarum prevents severe pathogenesis in mice infected with Leptospira interrogans and may be associated with recruitment of myeloid cells. PLoS Negl Trop Dis 2017; 11:e0005870. [PMID: 28841659 PMCID: PMC5589268 DOI: 10.1371/journal.pntd.0005870] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 09/07/2017] [Accepted: 08/11/2017] [Indexed: 02/03/2023] Open
Abstract
Recent estimates on global morbidity and mortality caused by Leptospirosis point to one million cases and almost 60,000 deaths a year worldwide, especially in resource poor countries. We analyzed how a commensal probiotic immunomodulator, Lactobacillus plantarum, affects Leptospira interrogans pathogenesis in a murine model of sub-lethal leptospirosis. We found that repeated oral pre-treatment of mice with live L. plantarum restored body weight to normal levels in mice infected with L. interrogans. Pre-treatment did not prevent L. interrogans access to the kidney but it affected the inflammatory response and it reduced histopathological signs of disease. Analysis of the immune cell profiles in lymphoid tissues of mice pre-treated with L. plantarum showed increased numbers of B cells as well as naïve and memory CD4+ helper T cell populations in uninfected mice that shifted towards increased numbers of effector CD4+ helper T in infected mice. CD8+ cytotoxic T cell profiles in pre-treated uninfected and infected mice mirrored the switch observed for CD4+ except that CD8+ memory T cells were not affected. In addition, pre-treatment led to increased populations of monocytes in lymphoid tissues of uninfected mice and to increased populations of macrophages in the same tissues of infected mice. Immunohistochemistry of kidney sections of pre-treated infected mice showed an enrichment of neutrophils and macrophages and a reduction of total leucocytes and T cells. Our results suggest that complex myeloid and T cell responses orchestrate the deployment of monocytes and other cells from lymphoid tissue and the recruitment of neutrophils and macrophages to the kidney, and that, the presence of these cells in the target organ may be associated with reductions in pathogenesis observed in infected mice treated with L. plantarum. Leptospirosis is an emerging neglected zoonotic disease with worldwide distribution that affects nearly all vertebrates and causes infection in ~1 million people on a yearly basis. Effective cross-protective vaccines are not available and antibiotic treatment is only effective if used early in the course of infection. In this study we describe how repeated oral treatment of mice with a commonly used probiotic, Lactobacillus plantarum, did not completely prevent colonization of the kidney by Leptospira interrogans but it did reduce signs and symptoms of leptospirosis. We also analyzed a number of immune cell types in spleen, lymph nodes and kidney after treatment and found that complex responses orchestrate the deployment of phagocytes to the kidney in infected mice. Our results suggest that pre-treatment with L. plantarum modulates systemic immune responses in a beneficial way in a mammalian host later exposed to L. interrogans infection.
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Affiliation(s)
- Hari-Hara Potula
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Luciana Richer
- Immuno Technologies Inc., Memphis, Tennessee, United States of America
| | - Catherine Werts
- Institut Pasteur, Unit Biology and Genetics of the Bacterial Cell Wall, Paris, France
- INSERM, Équipe Avenir, Paris, France
| | - Maria Gomes-Solecki
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
- Immuno Technologies Inc., Memphis, Tennessee, United States of America
- * E-mail:
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17
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Xia B, Sun L, Fan X, Xiao H, Zhu Y, Qin J, Cai C, Zhao W, Chang YF, Zhang Y, Guo X, He P. A new model of self-resolving leptospirosis in mice infected with a strain of Leptospira interrogans serovar Autumnalis harboring LPS signaling only through TLR4. Emerg Microbes Infect 2017; 6:e36. [PMID: 28536433 PMCID: PMC5520481 DOI: 10.1038/emi.2017.16] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/19/2017] [Accepted: 02/13/2017] [Indexed: 12/14/2022]
Abstract
Leptospirosis is an emerging worldwide zoonosis caused by pathogenic Leptospira spp. Our understanding of leptospirosis pathogenesis and host immune response remains limited, while mechanistic studies are hindered by a lack of proper animal models and immunological reagents. Here we established a murine model of acute and self-resolving leptospirosis by infecting 10-week-old C57BL/6 mice with Leptospira interrogans serovar Autumnalis strain 56606v, with characteristic manifestations including jaundice as well as subcutaneous and pulmonary bleeding, but no kidney lesions. We also verified that the lipopolysaccharide (LPS) of strain 56606v signaled through a TLR4-dependent pathway in murine bone marrow-derived macrophages (BMDMs), rather than the previously reported TLR2. In addition, upon infection with Leptospira strain 56606v, TLR4−/− C57BL/6 mice presented more severe jaundice and liver injury as well as higher bacterial loads than WT mice but milder pulmonary hemorrhaging. Molecular studies showed that leptospirosis-related bleeding coincides with the temporal kinetics of iNOS production, while jaundice and liver injury are probably due to insufficiently controlled bacterial loads in the liver. These results suggested that TLR4 is essential in mediating host leptospiral clearance and, to some extent, is associated with pulmonary and subcutaneous hemorrhage, probably through downstream inflammatory mediators, iNOS in particular. Overall, our murine model using immunocompetent mice might facilitate future studies into the pathogenesis of jaundice and bleeding in leptospirosis. Meanwhile, our study suggests the prospect of combining antibiotics and immunosuppressants in the treatment of severe leptospirosis presenting with pulmonary hemorrhage.
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Affiliation(s)
- Bili Xia
- Department of Microbiology and Immunology, Institutes of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.,Shanghai Public Health Clinical Center, Fudan University, Shanghai 201508, China
| | - Le Sun
- Department of Microbiology and Immunology, Institutes of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xia Fan
- Department of Microbiology and Immunology, Institutes of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Haihan Xiao
- Department of Microbiology and Immunology, Institutes of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yongzhang Zhu
- Department of Microbiology and Immunology, Institutes of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jinhong Qin
- Department of Microbiology and Immunology, Institutes of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Chengsong Cai
- Department of Laboratory Medicine, Affiliated Hospital of Hangzhou Normal University, Hangzhou 311121, Zhejiang Province, China
| | - Wei Zhao
- Department of Microbiology and Immunology, Institutes of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yung-Fu Chang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Yan Zhang
- Department of Microbiology and Immunology, Institutes of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xiaokui Guo
- Department of Microbiology and Immunology, Institutes of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Ping He
- Department of Microbiology and Immunology, Institutes of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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18
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Eyedrop Inoculation Causes Sublethal Leptospirosis in Mice. Infect Immun 2017; 85:IAI.01050-16. [PMID: 28115508 DOI: 10.1128/iai.01050-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 01/18/2017] [Indexed: 01/17/2023] Open
Abstract
Leptospirosis is potentially a fatal zoonosis acquired by contact of skin and mucosal surfaces with soil and water contaminated with infected urine. We analyzed the outcome of infection of C3H/HeJ mice with Leptospira interrogans serovar Copenhageni using an enzootic mode of transmission, the conjunctival route. Infection led to weight loss and L. interrogans dissemination from blood to urine, and spirochetes were detected in blood and urine simultaneously. The infectious dose that led to consistent dissemination to kidney after conjunctival infection was ∼108 leptospires. Interestingly, a lower number of spirochetes appeared to colonize the kidney, given that we quantified ∼105 and ∼10 leptospires per μl of urine and per μg of kidney, respectively. Leptospira-specific IgM and IgG were detected at 15 days postinfection, and isotyping of the Ig subclass showed that the total IgG response switched from an IgG1 response to an IgG3 response after infection with L. interrogans Histological periodic acid-Schiff D staining of infected kidney showed interstitial nephritis, mononuclear cell infiltrates, and reduced size of glomeruli. Quantification of proinflammatory immunomediators in kidney showed that keratinocyte-derived chemokine, macrophage inflammatory protein 2, RANTES, tumor necrosis factor alpha, gamma interferon, and interleukin-10 were upregulated in infected mice. We show that the kinetics of disease progression after infection via the ocular conjunctiva is delayed compared with infection via the standard intraperitoneal route. Differences may be related to the number of L. interrogans spirochetes that succeed in overcoming the natural defenses of the ocular conjunctiva and transit through tissue.
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19
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Gomes-Solecki M, Santecchia I, Werts C. Animal Models of Leptospirosis: Of Mice and Hamsters. Front Immunol 2017; 8:58. [PMID: 28270811 PMCID: PMC5318464 DOI: 10.3389/fimmu.2017.00058] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 01/16/2017] [Indexed: 01/27/2023] Open
Abstract
Pathogenic Leptospira sp. are spirochetal bacteria responsible for leptospirosis, an emerging worldwide zoonosis. These spirochetes are very successful pathogens that infect a wide range of hosts such as fish, reptiles, birds, marsupials, and mammals. Transmission occurs when chronically infected animals excrete live bacteria in their urine, contaminating the environment. Leptospira sp. enter their hosts through damaged skin and mucosa. Chronically infected rats and mice are asymptomatic and are considered as important reservoirs of the disease. Infected humans may develop either a flu-like, usually mild illness with or without chronic asymptotic renal colonization, or a severe acute disease with kidney, liver, and heart failure, potentially leading to death. Leptospirosis is an economic burden on society due to health-care costs related to elevated morbidity of humans and loss of animals of agricultural interest. There are no effective vaccines against leptospirosis. Leptospira sp. are difficult to genetically manipulate which delays the pace of research progress. In this review, we discuss in an historical perspective how animal models have contributed to further our knowledge of leptospirosis. Hamsters, guinea pigs, and gerbils have been instrumental to study the pathophysiology of acute lethal leptospirosis and the Leptospira sp. genes involved in virulence. Chronic renal colonization has been mostly studied using experimentally infected rats. A special emphasis will be placed on mouse models, long thought to be irrelevant since they survive lethal infection. However, mice have recently been shown to be good models of sublethal infection leading to chronic colonization. Furthermore, congenic and transgenic mice have proven essential to study how innate immune cells interact with the pathogen and to understand the role of the toll-like receptor 4, which is important to control Leptospira sp. load and disease. The use of inbred and transgenic mouse models opens up the field to the comprehensive study of immune responses to Leptospira sp. infection and subsequent pathophysiology of inflammation. It also allows for testing of drugs and vaccines in a biological system that can avail of a wealth of molecular tools that enable understanding of the mechanisms of action of protective vaccines.
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Affiliation(s)
- Maria Gomes-Solecki
- Department of Microbiology, Immunology and Biochemistry, The University of Tennessee Health Science Center , Memphis, TN , USA
| | - Ignacio Santecchia
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France; INSERM, équipe Avenir, Paris, France
| | - Catherine Werts
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France; INSERM, équipe Avenir, Paris, France
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20
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Devlin AA, Halvorsen PJ, Miller JC, Laster SM. Il-10 deficient mice express IFN-γ mRNA and clear Leptospira interrogans from their kidneys more rapidly than normal C57BL/6 mice. Immunobiology 2017; 222:768-777. [PMID: 28237664 DOI: 10.1016/j.imbio.2017.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/07/2017] [Accepted: 02/08/2017] [Indexed: 12/28/2022]
Abstract
Leptospira interrogans (L. interrogans), the causative agent of leptospirosis, is a widespread zoonotic spirochete that lives a dual lifestyle. L. interrogans infects mice, rats, and wildlife in a persistent and asymptomatic fashion, while also causing productive and acute infections in other mammals such as humans and hamsters. Infections in humans can be fatal, accompanied by a cytokine storm and shock-like symptoms. Production of IL-10 has been noted in both rodent and human infections which has led a number of investigators to hypothesize that IL-10 plays a role in the pathogenesis of this disease. To test this hypothesis we have compared bacteremia and the cytokine response of normal and IL-10 deficient C57Bl/6 mice following ip infection with L. interrogans. In normal mice bacterial 16s mRNA was detected in both lung and kidney tissues within a day after infection. Levels of 16s mRNA then dropped in both organs with complete elimination from the lung by day 3 but persistence in the kidney for 7days after infection. In contrast, in IL-10 deficient mice, the organism was eliminated more rapidly from the kidney. We found that infection of both control and IL-10 deficient mice produced similar levels of a number of pro-inflammatory cytokine mRNAs. On the other hand, IFN-γ mRNA was only induced in IL-10 deficient mice. These results support the hypothesis that L. interrogans ability to induce IL-10, which in turn prevents production of IFN-γ and inhibits T cell immunity, may contribute to the persistent growth of this microorganism in the murine kidney.
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Affiliation(s)
- Amy A Devlin
- Reynolds American, Inc. 401 N. Main St., Winston Salem, NC 27101, United States
| | - Priya J Halvorsen
- Immunity, Inflammation and Disease Laboratory, Division of Intramural Research, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, United States
| | - Jennifer C Miller
- Galaxy Diagnostics, Inc. 7020 Kit Creek Rd., Ste 130, Research Triangle Park, NC 27709, United States
| | - Scott M Laster
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States.
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Buyuktimkin B, Saier MH. Comparative analyses of transport proteins encoded within the genomes of Leptospira species. Microb Pathog 2016; 98:118-31. [PMID: 27296707 DOI: 10.1016/j.micpath.2016.06.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 06/08/2016] [Indexed: 02/02/2023]
Abstract
Select species of the bacterial genus Leptospira are causative agents of leptospirosis, an emerging global zoonosis affecting nearly one million people worldwide annually. We examined two Leptospira pathogens, Leptospira interrogans serovar Lai str. 56601 and Leptospira borgpetersenii serovar Hardjo-bovis str. L550, as well as the free-living leptospiral saprophyte, Leptospira biflexa serovar Patoc str. 'Patoc 1 (Ames)'. The transport proteins of these leptospires were identified and compared using bioinformatics to gain an appreciation for which proteins may be related to pathogenesis and saprophytism. L. biflexa possesses a disproportionately high number of secondary carriers for metabolite uptake and environmental adaptability as well as an increased number of inorganic cation transporters providing ionic homeostasis and effective osmoregulation in a rapidly changing environment. L. interrogans and L. borgpetersenii possess far fewer transporters, but those that they all have are remarkably similar, with near-equivalent representation in most transporter families. These two Leptospira pathogens also possess intact sphingomyelinases, holins, and virulence-related outer membrane porins. These virulence-related factors, in conjunction with decreased transporter substrate versatility, indicate that pathogenicity arose in Leptospira correlating to progressively narrowing ecological niches and the emergence of a limited set of proteins responsible for host invasion. The variability of host tropism and mortality rates by infectious leptospires suggests that small differences in individual sets of proteins play important physiological and pathological roles.
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Affiliation(s)
- Bora Buyuktimkin
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Milton H Saier
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA.
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22
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Matsui M, Roche L, Geroult S, Soupé-Gilbert ME, Monchy D, Huerre M, Goarant C. Cytokine and Chemokine Expression in Kidneys during Chronic Leptospirosis in Reservoir and Susceptible Animal Models. PLoS One 2016; 11:e0156084. [PMID: 27219334 PMCID: PMC4878748 DOI: 10.1371/journal.pone.0156084] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 05/09/2016] [Indexed: 01/24/2023] Open
Abstract
Leptospirosis is caused by pathogenic spirochetes of the genus Leptospira. Humans can be infected after exposure to contaminated urine of reservoir animals, usually rodents, regarded as typical asymptomatic carriers of leptospires. In contrast, accidental hosts may present an acute form of leptospirosis with a range of clinical symptoms including the development of Acute Kidney Injury (AKI). Chronic Kidney Disease (CKD) is considered as a possible AKI-residual sequela but little is known about the renal pathophysiology consequent to leptospirosis infection. Herein, we studied the renal morphological alterations in relation with the regulation of inflammatory cytokines and chemokines, comparing two experimental models of chronic leptospirosis, the golden Syrian hamster that survived the infection, becoming carrier of virulent leptospires, and the OF1 mouse, a usual reservoir of the bacteria. Animals were monitored until 28 days after injection with a virulent L. borgpetersenii serogroup Ballum to assess chronic infection. Hamsters developed morphological alterations in the kidneys with tubulointerstitial nephritis and fibrosis. Grading of lesions revealed higher scores in hamsters compared to the slight alterations observed in the mouse kidneys, irrespective of the bacterial load. Interestingly, pro-fibrotic TGF-β was downregulated in mouse kidneys. Moreover, cytokines IL-1β and IL-10, and chemokines MIP-1α/CCL3 and IP-10/CXCL-10 were significantly upregulated in hamster kidneys compared to mice. These results suggest a possible maintenance of inflammatory processes in the hamster kidneys with the infiltration of inflammatory cells in response to bacterial carriage, resulting in alterations of renal tissues. In contrast, lower expression levels in mouse kidneys indicated a better regulation of the inflammatory response and possible resolution processes likely related to resistance mechanisms.
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Affiliation(s)
- Mariko Matsui
- Institut Pasteur International Network, Institut Pasteur de Nouvelle-Calédonie, Leptospirosis Research and Expertise Unit, Noumea, New Caledonia
| | - Louise Roche
- Institut Pasteur International Network, Institut Pasteur de Nouvelle-Calédonie, Leptospirosis Research and Expertise Unit, Noumea, New Caledonia
| | - Sophie Geroult
- Institut Pasteur International Network, Institut Pasteur de Nouvelle-Calédonie, Leptospirosis Research and Expertise Unit, Noumea, New Caledonia
| | - Marie-Estelle Soupé-Gilbert
- Institut Pasteur International Network, Institut Pasteur de Nouvelle-Calédonie, Leptospirosis Research and Expertise Unit, Noumea, New Caledonia
| | - Didier Monchy
- Anatomic Pathology Laboratory, Gaston-Bourret Territorial Hospital Center, Noumea, New Caledonia
| | - Michel Huerre
- Unité de Recherche et Expertise en Histotechnologie et Pathologie, Institut Pasteur, Paris, France.,Departement de Pathologie, Institut Curie, Paris, France
| | - Cyrille Goarant
- Institut Pasteur International Network, Institut Pasteur de Nouvelle-Calédonie, Leptospirosis Research and Expertise Unit, Noumea, New Caledonia
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Jayaraman PA, Devlin AA, Miller JC, Scholle F. The adaptor molecule Trif contributes to murine host defense during Leptospiral infection. Immunobiology 2016; 221:964-74. [PMID: 27259371 DOI: 10.1016/j.imbio.2016.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 05/03/2016] [Accepted: 05/23/2016] [Indexed: 12/17/2022]
Abstract
Leptospirosis is a zoonotic disease and is caused by pathogenic species of the Leptospira genus, including Leptospira interrogans (L. interrogans). Humans, domestic and wild animals are susceptible to acute or chronic infection. The innate immune response is a critical defense mechanism against Leptospira interrogans, and has been investigated in mouse models. Murine Toll-like receptors (TLRs) have been shown to be key factors in sensing and responding to L. interrogans infection. Specifically, TLR2, TLR4 and the TLR adaptor molecule MyD88 are essential for host defense against L. interrogans; however, the role of the TLR adaptor molecule TIR-domain-containing adaptor-inducing interferon β (TRIF) in the response to L. interrogans has not been previously determined. In the present study, TRIF was found to play an important role during leptospiral infection. Following challenge with L. interrogans, Trif(-/-) mice exhibited delayed weight gain compared to wild-type mice. Moreover, Trif(-/-) mice exhibited an increase in L. interrogans burden in the kidneys, lungs, and blood at early time points (less than 7days post infection). Multiple components of the innate immune responses were dampened in response to leptospiral infection including transcription and production of cytokines, and the humoral response, which suggested that TRIF contributes to expression and production of cytokines important for the host defense against L. interrogans.
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Affiliation(s)
- Priya A Jayaraman
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States
| | - Amy A Devlin
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States
| | - Jennifer C Miller
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States
| | - Frank Scholle
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States.
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Buyuktimkin B, Saier MH. Comparative genomic analyses of transport proteins encoded within the genomes of Leptospira species. Microb Pathog 2015; 88:52-64. [PMID: 26247102 DOI: 10.1016/j.micpath.2015.07.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 07/21/2015] [Accepted: 07/23/2015] [Indexed: 11/17/2022]
Abstract
Select species of the bacterial genus Leptospira are causative agents of leptospirosis, an emerging global zoonosis affecting nearly one million people worldwide annually. We examined two Leptospira pathogens, Leptospira interrogans serovar Lai str. 56601 and Leptospira borgpetersenii serovar Hardjo-bovis str. L550, as well as the free-living leptospiral saprophyte, Leptospira biflexa serovar Patoc str. 'Patoc 1 (Ames)'. The transport proteins of these leptospires were identified and compared using bioinformatics to gain an appreciation for which proteins may be related to pathogenesis and saprophytism. L. biflexa possesses a disproportionately high number of secondary carriers for metabolite uptake and environmental adaptability as well as an increased number of inorganic cation transporters providing ionic homeostasis and effective osmoregulation in a rapidly changing environment. L. interrogans and L. borgpetersenii possess far fewer transporters, but those that they have are remarkably similar, with near-equivalent representation in most transporter families. These two Leptospira pathogens also possess intact sphingomyelinases, holins, and virulence-related outer membrane porins. These virulence-related factors, in conjunction with decreased transporter substrate versatility, indicate that pathogenicity was accompanied by progressively narrowing ecological niches and the emergence of a limited set of proteins responsible for host invasion. The variability of host tropism and mortality rates by infectious leptospires suggests that small differences in individual sets of proteins play important physiological and pathological roles.
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Affiliation(s)
- Bora Buyuktimkin
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Milton H Saier
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA.
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Scharrig E, Carestia A, Ferrer MF, Cédola M, Pretre G, Drut R, Picardeau M, Schattner M, Gómez RM. Neutrophil Extracellular Traps are Involved in the Innate Immune Response to Infection with Leptospira. PLoS Negl Trop Dis 2015; 9:e0003927. [PMID: 26161745 PMCID: PMC4498591 DOI: 10.1371/journal.pntd.0003927] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 06/20/2015] [Indexed: 12/30/2022] Open
Abstract
NETosis is a process by which neutrophils extrude their DNA together with bactericidal proteins that trap and/or kill pathogens. In the present study, we evaluated the ability of Leptospira spp. to induce NETosis using human ex vivo and murine in vivo models. Microscopy and fluorometric studies showed that incubation of human neutrophils with Leptospira interrogans serovar Copenhageni strain Fiocruz L1-130 (LIC) resulted in the release of DNA extracellular traps (NETs). The bacteria number, pathogenicity and viability were relevant factors for induction of NETs, but bacteria motility was not. Entrapment of LIC in the NETs resulted in LIC death; however, pathogenic but not saprophytic Leptospira sp. exerted nuclease activity and degraded DNA. Mice infected with LIC showed circulating NETs after 2 days post-infection (dpi). Depletion of neutrophils with mAb1A8 significantly reduced the amount of intravascular NETs in LIC-infected mice, increasing bacteremia at 3 dpi. Although there was a low bacterial burden, scarce neutrophils and an absence of inflammation in the early stages of infection in the kidney and liver, at the beginning of the leptospiruric phase, the bacterial burden was significantly higher in kidneys of neutrophil-depleted-mice compared to non-depleted and infected mice. Surprisingly, interstitial nephritis was of similar intensity in both groups of infected mice. Taken together, these data suggest that LIC triggers NETs, and that the intravascular formation of these DNA traps appears to be critical not only to prevent early leptospiral dissemination but also to preclude further bacterial burden. Neutrophils extracellular traps (NETs) are a relatively novel pathogen-killing mechanism for extracellular microbes independent of phagocytic uptake and degranulation. Although it was originally proposed that NETs are formed exclusively in tissues at sites of infection, NETs have also been found within blood vessels where they ensnare microbes in circulation during sepsis. Leptospirosis is a global zoonosis that has become prevalent in slum areas, where its diagnosis and treatment may be overlooked. Here, for the first time, we characterized NETs formation as a result of Leptospira spp. stimulus. We also showed that mice lacking neutrophils exhibit early reduced levels of circulating NETs, but higher bacteremia, a fact that was later associated with higher bacterial burden in kidney. The present results demonstrate that Leptospira spp. can trigger NET formation and that this innate immune mechanism can play a role in the pathogenesis of leptospirosis.
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Affiliation(s)
- Emilia Scharrig
- Laboratory of Animal Viruses, Institute of Biotechnology and Molecular Biology, CCT-La Plata, CONICET-UNLP, Buenos Aires, Argentina
| | - Agostina Carestia
- Laboratory of Experimental Thrombosis, Institute of Experimental Medicine, CONICET-National Academy of Medicine, Buenos Aires, Argentina
| | - María F. Ferrer
- Laboratory of Animal Viruses, Institute of Biotechnology and Molecular Biology, CCT-La Plata, CONICET-UNLP, Buenos Aires, Argentina
| | - Maia Cédola
- Laboratory of Animal Viruses, Institute of Biotechnology and Molecular Biology, CCT-La Plata, CONICET-UNLP, Buenos Aires, Argentina
| | - Gabriela Pretre
- Laboratory of Animal Viruses, Institute of Biotechnology and Molecular Biology, CCT-La Plata, CONICET-UNLP, Buenos Aires, Argentina
| | - Ricardo Drut
- Division of Pathology, Children Hospital “Superiora Sor María Ludovica”, La Plata, Argentina
- Cátedra de Patología “A”, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina
| | | | - Mirta Schattner
- Laboratory of Experimental Thrombosis, Institute of Experimental Medicine, CONICET-National Academy of Medicine, Buenos Aires, Argentina
- * E-mail: (MS); (RMG)
| | - Ricardo M. Gómez
- Laboratory of Animal Viruses, Institute of Biotechnology and Molecular Biology, CCT-La Plata, CONICET-UNLP, Buenos Aires, Argentina
- * E-mail: (MS); (RMG)
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26
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Ratet G, Veyrier FJ, Fanton d'Andon M, Kammerscheit X, Nicola MA, Picardeau M, Boneca IG, Werts C. Live imaging of bioluminescent leptospira interrogans in mice reveals renal colonization as a stealth escape from the blood defenses and antibiotics. PLoS Negl Trop Dis 2014; 8:e3359. [PMID: 25474719 PMCID: PMC4256284 DOI: 10.1371/journal.pntd.0003359] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 10/18/2014] [Indexed: 01/02/2023] Open
Abstract
Leptospira (L.) interrogans are bacteria responsible for a worldwide reemerging zoonosis. Some animals asymptomatically carry L. interrogans in their kidneys and excrete bacteria in their urine, which contaminates the environment. Humans are infected through skin contact with leptospires and develop mild to severe leptospirosis. Previous attempts to construct fluorescent or bioluminescent leptospires, which would permit in vivo visualization and investigation of host defense mechanisms during infection, have been unsuccessful. Using a firefly luciferase cassette and random transposition tools, we constructed bioluminescent chromosomal transformants in saprophytic and pathogenic leptospires. The kinetics of leptospiral dissemination in mice, after intraperitoneal inoculation with a pathogenic transformant, was tracked by bioluminescence using live imaging. For infective doses of 106 to 107 bacteria, we observed dissemination and exponential growth of leptospires in the blood, followed by apparent clearance of bacteria. However, with 2×108 bacteria, the septicemia led to the death of mice within 3 days post-infection. In surviving mice, one week after infection, pathogenic leptospires reemerged only in the kidneys, where they multiplied and reached a steady state, leading to a sustained chronic renal infection. These experiments reveal that a fraction of the leptospiral population escapes the potent blood defense, and colonizes a defined number of niches in the kidneys, proportional to the infective dose. Antibiotic treatments failed to eradicate leptospires that colonized the kidneys, although they were effective against L. interrogans if administered before or early after infection. To conclude, mice infected with bioluminescent L. interrogans proved to be a novel model to study both acute and chronic leptospirosis, and revealed that, in the kidneys, leptospires are protected from antibiotics. These bioluminescent leptospires represent a powerful new tool to challenge mice treated with drugs or vaccines, and test the survival, dissemination, and transmission of leptospires between environment and hosts. Leptospirosis is a worldwide neglected disease caused by the pathogenic bacterium named Leptospira interrogans. Some rodents, such as rats, do not get sick from leptospirosis and constitute a reservoir. They carry leptospires in their kidneys and excrete the bacteria in the environment. L. interrogans are mobile and penetrate their hosts through abraded skin or mucosa. Infected humans may develop mild to severe leptospirosis, potentially leading to death. Leptospires are difficult to cultivate and to genetically manipulate, impairing the study of leptospirosis. Here, we constructed bioluminescent leptospires, and monitored infection in live mice by tracking bioluminescence. In the first days after infection, a rapid dissemination and growth of bacteria was observed in the blood circulation, followed around one week after the infection by their apparent disappearance. However, the leptospires reemerged and multiplied in the kidneys, to reach sustained levels three weeks after infection. The use of antibiotics showed that antibiotic-susceptible L. interrogans are very difficult to eradicate once they are settled in the kidneys. Mice infected with bioluminescent leptospires represent a pertinent model to study leptospirosis. These bioluminescent leptospires are novel tools that will be useful to test the efficacy of treatments or vaccines against leptospirosis.
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Affiliation(s)
- Gwenn Ratet
- Institut Pasteur, Unité Biologie et Génétique des parois bactériennes, Paris, France
- INSERM, équipe Avenir, Paris, France
| | - Frédéric J. Veyrier
- Institut Pasteur, Unité Biologie et Génétique des parois bactériennes, Paris, France
- INSERM, équipe Avenir, Paris, France
- Institut Pasteur, Unité des infections bactériennes invasives, Paris, France
| | - Martine Fanton d'Andon
- Institut Pasteur, Unité Biologie et Génétique des parois bactériennes, Paris, France
- INSERM, équipe Avenir, Paris, France
| | - Xavier Kammerscheit
- Institut Pasteur, Unité Biologie et Génétique des parois bactériennes, Paris, France
- INSERM, équipe Avenir, Paris, France
- ENS Cachan, département de Biologie, Paris, France
| | | | | | - Ivo G. Boneca
- Institut Pasteur, Unité Biologie et Génétique des parois bactériennes, Paris, France
- INSERM, équipe Avenir, Paris, France
| | - Catherine Werts
- Institut Pasteur, Unité Biologie et Génétique des parois bactériennes, Paris, France
- INSERM, équipe Avenir, Paris, France
- * E-mail:
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