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Hsu SH, Yang CW. Insight into the Structure, Functions, and Dynamics of the Leptospira Outer Membrane Proteins with the Pathogenicity. MEMBRANES 2022; 12:membranes12030300. [PMID: 35323775 PMCID: PMC8951592 DOI: 10.3390/membranes12030300] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/25/2022] [Accepted: 03/01/2022] [Indexed: 02/01/2023]
Abstract
Leptospirosis is a widespread zoonosis that frequently occurs in tropical and subtropical countries. Leptospira enters the host through wounds or mucous membranes and spreads to the whole body through the blood, causing systemic infection. Kidneys are the preferential site where Leptospira accumulates, especially in the renal interstitium and renal tubule epithelial cells. Clinical symptoms in humans include high fever, jaundice, renal failure, and severe multiple-organ failure (Weil’s syndrome). Surface-exposed antigens are located at the outermost layer of Leptospira and these potential virulence factors are likely involved in primary host-pathogen interactions, adhesion, and/or invasion. Using the knockout/knockdown techniques to the evaluation of pathogenicity in the virulence factor are the most direct and effective methods and many virulence factors are evaluated including lipopolysaccharides (LPS), Leptospira lipoprotein 32 (LipL32), Leptospira ompA domain protein 22 (Loa22), LipL41, LipL71, Leptospira immunoglobulin-like repeat A (LigA), LigB, and LipL21. In this review, we will discuss the structure, functions, and dynamics of these virulence factors and the roles of these virulence factors in Leptospira pathogenicity. In addition, a protein family with special Leucine-rich repeat (LRR) will also be discussed for their vital role in Leptospira pathogenicity. Finally, these surface-exposed antigens are discussed in the application of the diagnosis target for leptospirosis and compared with the serum microscope agglutination test (MAT), the gold standard for leptospirosis.
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Passalia FJ, Heinemann MB, Vieira ML, Nascimento ALTO. A Novel Leptospira interrogans Protein LIC13086 Inhibits Fibrin Clot Formation and Interacts With Host Components. Front Cell Infect Microbiol 2021; 11:708739. [PMID: 34277477 PMCID: PMC8280789 DOI: 10.3389/fcimb.2021.708739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 06/08/2021] [Indexed: 11/13/2022] Open
Abstract
Leptospirosis is a neglected zoonosis, caused by pathogenic spirochetes bacteria of the genus Leptospira. The molecular mechanisms of leptospirosis infection are complex, and it is becoming clear that leptospires express several functionally redundant proteins to invade, disseminate, and escape the host’s immune response. Here, we describe a novel leptospiral protein encoded by the gene LIC13086 as an outer membrane protein. The recombinant protein LIC13086 can interact with the extracellular matrix component laminin and bind plasminogen, thus possibly participating during the adhesion process and dissemination. Also, by interacting with fibrinogen and plasma fibronectin, the protein LIC13086 probably has an inhibitory effect in the fibrin clot formation during the infection process. The newly characterized protein can also bind molecules of the complement system and the regulator C4BP and, thus, might have a role in the evasion mechanism of Leptospira. Taken together, our results suggest that the protein LIC13086 may have a multifunctional role in leptospiral pathogenesis, participating in host invasion, dissemination, and immune evasion processes.
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Affiliation(s)
- Felipe José Passalia
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, Brazil.,Programa de Pós-Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Marcos Bryan Heinemann
- Laboratório de Zoonoses Bacterianas, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil
| | - Mônica Larucci Vieira
- Departamento de Microbiologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
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Liu J, Xie X, Zhang W, Cao Y. Immune-enhanced effect of Iris polysaccharide is protective against leptospirosis. Microb Pathog 2021; 154:104855. [PMID: 33757897 DOI: 10.1016/j.micpath.2021.104855] [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: 01/12/2021] [Revised: 03/10/2021] [Accepted: 03/12/2021] [Indexed: 10/21/2022]
Abstract
Leptospirosis, caused by pathogenic Leptospira species, is an essential but neglected zoonosis. There are more than 300 serovars of pathogenic Leptospira, while inactivated bacteria offers only short-term serovar-specific protection. Leptospirosis treatment is mainly dependent on the use of antibiotics. However, the side effects of antibiotics and the risk of antibiotic resistance remain major problems. Thus, alternative agents which are fewer side effects on humans and efficient in leptospirosis would be welcome. Many studies have reported that polysaccharides could be used as immunostimulants in treating infection and cancer. In this study, we examined the protective effect of polysaccharides isolated from Iris against leptospirosis. To our knowledge, it is the first time to report Iris polysaccharides (IP) as an immunostimulant in treating infection. The results showed that IP treatment significantly increased the survival rate of hamsters challenged by a lethal dose of leptospires. Besides, the tissue injury and leptospiral load were reduced in IP-treated infection group compared with the untreated infection group at 4 days post-infection (p.i.). Intriguingly, IP treatment sustained intense immune response at 4 days p.i. analyzed by qPCR. The results exhibited that the gene expression of TLR2 and TLR4 was significantly increased in the group coinjected with IP and leptospires than in the infected controls. And the expression of IL-1β and TNF-α were also up-regulated after IP treatment, except the expression of IL-1β in the kidney. Our results not only broaden the medicinal value of Iris, but also provide a competent candidate for the control of Leptospira infection.
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Affiliation(s)
- Jiuxi Liu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, 130062, People's Republic of China
| | - Xufeng Xie
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, 130062, People's Republic of China
| | - Wenlong Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, 130062, People's Republic of China.
| | - Yongguo Cao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, 130062, People's Republic of China.
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Haake DA, Matsunaga J. Leptospiral Immunoglobulin-Like Domain Proteins: Roles in Virulence and Immunity. Front Immunol 2021; 11:579907. [PMID: 33488581 PMCID: PMC7821625 DOI: 10.3389/fimmu.2020.579907] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 11/05/2020] [Indexed: 02/03/2023] Open
Abstract
The virulence mechanisms required for infection and evasion of immunity by pathogenic Leptospira species remain poorly understood. A number of L. interrogans surface proteins have been discovered, lying at the interface between the pathogen and host. Among these proteins, the functional properties of the Lig (leptospiral immunoglobulin-like domain) proteins have been examined most thoroughly. LigA, LigB, and LigC contain a series of, 13, 12, and 12 closely related domains, respectively, each containing a bacterial immunoglobulin (Big) -like fold. The multidomain region forms a mostly elongated structure that exposes a large surface area. Leptospires wield the Lig proteins to promote interactions with a range of specific host proteins, including those that aid evasion of innate immune mechanisms. These diverse binding events mediate adhesion of L. interrogans to the extracellular matrix, inhibit hemostasis, and inactivate key complement proteins. These interactions may help L. interrogans overcome the physical, hematological, and immunological barriers that would otherwise prevent the spirochete from establishing a systemic infection. Despite significant differences in the affinities of the LigA and LigB proteins for host targets, their functions overlap during lethal infection of hamsters; virulence is lost only when both ligA and ligB transcription is knocked down simultaneously. Lig proteins have been shown to be promising vaccine antigens through evaluation of a variety of different adjuvant strategies. This review serves to summarize current knowledge of Lig protein roles in virulence and immunity and to identify directions needed to better understand the precise functions of the Lig proteins during infection.
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Affiliation(s)
- David A. Haake
- Division of Infectious Diseases, VA Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Departments of Medicine, and Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, United States
| | - James Matsunaga
- Research Service, VA Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, United States
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Santecchia I, Ferrer MF, Vieira ML, Gómez RM, Werts C. Phagocyte Escape of Leptospira: The Role of TLRs and NLRs. Front Immunol 2020; 11:571816. [PMID: 33123147 PMCID: PMC7573490 DOI: 10.3389/fimmu.2020.571816] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/16/2020] [Indexed: 12/21/2022] Open
Abstract
The spirochetal bacteria Leptospira spp. are causative agents of leptospirosis, a globally neglected and reemerging zoonotic disease. Infection with these pathogens may lead to an acute and potentially fatal disease but also to chronic asymptomatic renal colonization. Both forms of disease demonstrate the ability of leptospires to evade the immune response of their hosts. In this review, we aim first to recapitulate the knowledge and explore the controversial data about the opsonization, recognition, intracellular survival, and killing of leptospires by scavenger cells, including platelets, neutrophils, macrophages, and dendritic cells. Second, we will summarize the known specificities of the recognition or escape of leptospire components (the so-called microbial-associated molecular patterns; MAMPs) by the pattern recognition receptors (PRRs) of the Toll-like and NOD-like families. These PRRs are expressed by phagocytes, and their stimulation by MAMPs triggers pro-inflammatory cytokine and chemokine production and bactericidal responses, such as antimicrobial peptide secretion and reactive oxygen species production. Finally, we will highlight recent studies suggesting that boosting or restoring phagocytic functions by treatments using agonists of the Toll-like or NOD receptors represents a novel prophylactic strategy and describe other potential therapeutic or vaccine strategies to combat leptospirosis.
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Affiliation(s)
- Ignacio Santecchia
- Institut Pasteur, Microbiology Department, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie intégrative et Moléculaire, Paris, France.,INSERM, Equipe Avenir, Paris, France.,Université de Paris, Sorbonne Paris Cité, Paris, France
| | - María Florencia Ferrer
- Laboratorio de Virus Animales, Instituto de Biotecnología y Biología Molecular, CONICET-Universidad Nacional de La Plata, La Plata, Argentina
| | - Monica Larucci Vieira
- Departamento de Microbiologia, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Ricardo Martín Gómez
- Laboratorio de Virus Animales, Instituto de Biotecnología y Biología Molecular, CONICET-Universidad Nacional de La Plata, La Plata, Argentina
| | - Catherine Werts
- Institut Pasteur, Microbiology Department, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie intégrative et Moléculaire, Paris, France
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Vieira ML, Nascimento ALTO. Virulent Leptospira interrogans Induce Cytotoxic Effects in Human Platelets in vitro Through Direct Interactions. Front Microbiol 2020; 11:572972. [PMID: 33117318 PMCID: PMC7552899 DOI: 10.3389/fmicb.2020.572972] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/07/2020] [Indexed: 12/27/2022] Open
Abstract
Leptospirosis is a prevalent zoonotic disease, caused by bacteria of the genus Leptospira. Leptospirosis frequently leads to hemostatic disturbances, and the severe cases are marked by hemorrhages and low platelet number in circulation, which is associated with the patients’ poor outcomes. Nevertheless, Leptospira-platelet interactions remain poorly explored. In this study, we performed a series of in vitro experiments evaluating whether leptospires induce human platelet aggregation, activation, and morphological changes. Platelets were incubated with virulent L. interrogans and the platelet outcomes were assessed by aggregometry, flow cytometry, and scanning and transmission electron microscopy. Our results show that leptospires alone do not induce platelet aggregation and activation, and induce platelet cytotoxic effects instead, by clearly inducing platelet disruption and detachment. We show for the first time that virulent leptospires do interact directly with platelets, an event that could trigger pathophysiological effects during the infection. This study might serve as a basis for the development of novel treatments for the disease.
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Affiliation(s)
- Monica Larucci Vieira
- Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil.,Laboratório de Desenvolvimento de Vacinas, Butantan Institute, São Paulo, Brazil
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