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Valério-Bolas A, Meunier M, Palma-Marques J, Rodrigues A, Santos AM, Nunes T, Ferreira R, Armada A, Alves JC, Antunes W, Cardoso I, Mesquita-Gabriel S, Lobo L, Alexandre-Pires G, Marques L, Pereira da Fonseca I, Santos-Gomes G. Exploiting Leishmania-Primed Dendritic Cells as Potential Immunomodulators of Canine Immune Response. Cells 2024; 13:445. [PMID: 38474410 DOI: 10.3390/cells13050445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/23/2024] [Accepted: 02/26/2024] [Indexed: 03/14/2024] Open
Abstract
Dendritic cells (DCs) capture pathogens and process antigens, playing a crucial role in activating naïve T cells, bridging the gap between innate and acquired immunity. However, little is known about DC activation when facing Leishmania parasites. Thus, this study investigates in vitro activity of canine peripheral blood-derived DCs (moDCs) exposed to L. infantum and L. amazonensis parasites and their extracellular vesicles (EVs). L. infantum increased toll-like receptor 4 gene expression in synergy with nuclear factor κB activation and the generation of pro-inflammatory cytokines. This parasite also induced the expression of class II molecules of major histocompatibility complex (MHC) and upregulated co-stimulatory molecule CD86, which, together with the release of chemokine CXCL16, can attract and help in T lymphocyte activation. In contrast, L. amazonensis induced moDCs to generate a mix of pro- and anti-inflammatory cytokines, indicating that this parasite can establish a different immune relationship with DCs. EVs promoted moDCs to express class I MHC associated with the upregulation of co-stimulatory molecules and the release of CXCL16, suggesting that EVs can modulate moDCs to attract cytotoxic CD8+ T cells. Thus, these parasites and their EVs can shape DC activation. A detailed understanding of DC activation may open new avenues for the development of advanced leishmaniasis control strategies.
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Affiliation(s)
- Ana Valério-Bolas
- Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), 1349-008 Lisbon, Portugal
| | - Mafalda Meunier
- Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), 1349-008 Lisbon, Portugal
| | - Joana Palma-Marques
- Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), 1349-008 Lisbon, Portugal
| | - Armanda Rodrigues
- Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), 1349-008 Lisbon, Portugal
| | - Ana Margarida Santos
- Divisão de Medicina Veterinária, Guarda Nacional Republicana, 1200-771 Lisbon, Portugal
| | - Telmo Nunes
- Microscopy Center, Faculty of Sciences, University of Lisbon, 1749-016 Lisbon, Portugal
| | - Rui Ferreira
- Banco de Sangue Animal (BSA), 4100-462 Porto, Portugal
| | - Ana Armada
- Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), 1349-008 Lisbon, Portugal
| | - João Carlos Alves
- Divisão de Medicina Veterinária, Guarda Nacional Republicana, 1200-771 Lisbon, Portugal
| | - Wilson Antunes
- Unidade Militar Laboratorial de Defesa Biológica e Química (UMLDBQ), 1849-012 Lisbon, Portugal
| | - Inês Cardoso
- Banco de Sangue Animal (BSA), 4100-462 Porto, Portugal
| | - Sofia Mesquita-Gabriel
- Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), 1349-008 Lisbon, Portugal
| | - Lis Lobo
- Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), 1349-008 Lisbon, Portugal
| | - Graça Alexandre-Pires
- CIISA, Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1649-004 Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1200-771 Lisbon, Portugal
| | - Luís Marques
- BioSystems and Integrative Sciences Institute, Faculty of Sciences, University of Lisbon-FCUL-BioISI Ce3CE, 1749-016 Lisbon, Portugal
| | - Isabel Pereira da Fonseca
- CIISA, Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1649-004 Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1200-771 Lisbon, Portugal
| | - Gabriela Santos-Gomes
- Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), 1349-008 Lisbon, Portugal
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Kaushal RS, Naik N, Prajapati M, Rane S, Raulji H, Afu NF, Upadhyay TK, Saeed M. Leishmania species: A narrative review on surface proteins with structural aspects involved in host-pathogen interaction. Chem Biol Drug Des 2023; 102:332-356. [PMID: 36872849 DOI: 10.1111/cbdd.14227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/25/2023] [Accepted: 03/02/2023] [Indexed: 03/07/2023]
Abstract
In tropical and subtropical regions of the world, leishmaniasis is endemic and causes a range of clinical symptoms in people, from severe tegumentary forms (such as cutaneous, mucocutaneous, and diffuse leishmaniasis) to lethal visceral forms. The protozoan parasite of the genus Leishmania causes leishmaniasis, which is still a significant public health issue, according to the World Health Organization 2022. The public's worry about the neglected tropical disease is growing as new foci of the illness arise, which are exacerbated by alterations in behavior, changes in the environment, and an enlarged range of sand fly vectors. Leishmania research has advanced significantly during the past three decades in a few different avenues. Despite several studies on Leishmania, many issues, such as illness control, parasite resistance, parasite clearance, etc., remain unresolved. The key virulence variables that play a role in the pathogenicity-host-pathogen relationship of the parasite are comprehensively discussed in this paper. The important Leishmania virulence factors, such as Kinetoplastid Membrane Protein-11 (KMP-11), Leishmanolysin (GP63), Proteophosphoglycan (PPG), Lipophosphoglycan (LPG), Glycosylinositol Phospholipids (GIPL), and others, have an impact on the pathophysiology of the disease and enable the parasite to spread the infection. Leishmania infection may arise from virulence factors; they are treatable with medications or vaccinations more promptly and might greatly shorten the duration of treatment. Additionally, our research sought to present a modeled structure of a few putative virulence factors that might aid in the development of new chemotherapeutic approaches for the treatment of leishmaniasis. The predicted virulence protein's structure is utilized to design novel drugs, therapeutic targets, and immunizations for considerable advantage from a higher understanding of the host immune response.
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Affiliation(s)
- Radhey Shyam Kaushal
- Department of Biotechnology, Parul Institute of Applied Sciences and Centre of Research for Development, Parul University, Vadodara, 391760, Gujarat, India
| | - Nidhi Naik
- Department of Microbiology, Parul Institute of Applied Sciences, Parul University, Vadodara, 391760, Gujarat, India
| | - Maitri Prajapati
- Department of Microbiology, Parul Institute of Applied Sciences, Parul University, Vadodara, 391760, Gujarat, India
| | - Shruti Rane
- Department of Microbiology, Parul Institute of Applied Sciences, Parul University, Vadodara, 391760, Gujarat, India
| | - Himali Raulji
- Department of Microbiology, Parul Institute of Applied Sciences, Parul University, Vadodara, 391760, Gujarat, India
| | - Ngo Festus Afu
- Department of Biochemistry, Parul Institute of Applied Sciences, Parul University, Vadodara, 391760, Gujarat, India
| | - Tarun Kumar Upadhyay
- Department of Biotechnology, Parul Institute of Applied Sciences and Centre of Research for Development, Parul University, Vadodara, 391760, Gujarat, India
| | - Mohd Saeed
- Department of Biology, College of Sciences, University of Ha'il, P.O. Box 2440, Hail, 81411, Saudi Arabia
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3
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Al-Khalaifah HS. Major Molecular Factors Related to Leishmania Pathogenicity. Front Immunol 2022; 13:847797. [PMID: 35769465 PMCID: PMC9236557 DOI: 10.3389/fimmu.2022.847797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 04/05/2022] [Indexed: 11/13/2022] Open
Abstract
Leishmaniasis is a major health problem with 600k - 1M new cases worldwide and 1 billion at risk. It involves a wide range of clinical forms ranging from self-healing cutaneous lesions to systemic diseases that are fatal if not treated, depending on the species of Leishmania. Leishmania sp. are digenetic parasites that have two different morphological stages. Leishmania parasites possess a number of invasive/evasive and pathoantigenic determinants that seem to have critical roles in Leishmania infection of macrophages which leads to successful intracellular parasitism in the parasitophorous vacuoles. These determinants are traditionally known as “virulence factors”, and are considered to be good targets for developing specific inhibitors to attenuate virulence of Leishmania by gene deletions or modifications, thus causing infective, but non-pathogenic mutants for vaccination. Pathway of biosynthesis is critical for keeping the parasite viable and is important for drug designing against these parasites. These drugs are aimed to target enzymes that control these pathways. Accordingly, maintaining low level of parasitic infection and in some cases as a weapon to eradicate infection completely. The current paper focuses on several virulence factors as determinants of Leishmania pathogenicity, as well as the metabolites produced by Leishmania to secure its survival in the host.
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Borges AR, Link F, Engstler M, Jones NG. The Glycosylphosphatidylinositol Anchor: A Linchpin for Cell Surface Versatility of Trypanosomatids. Front Cell Dev Biol 2021; 9:720536. [PMID: 34790656 PMCID: PMC8591177 DOI: 10.3389/fcell.2021.720536] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 09/06/2021] [Indexed: 11/20/2022] Open
Abstract
The use of glycosylphosphatidylinositol (GPI) to anchor proteins to the cell surface is widespread among eukaryotes. The GPI-anchor is covalently attached to the C-terminus of a protein and mediates the protein’s attachment to the outer leaflet of the lipid bilayer. GPI-anchored proteins have a wide range of functions, including acting as receptors, transporters, and adhesion molecules. In unicellular eukaryotic parasites, abundantly expressed GPI-anchored proteins are major virulence factors, which support infection and survival within distinct host environments. While, for example, the variant surface glycoprotein (VSG) is the major component of the cell surface of the bloodstream form of African trypanosomes, procyclin is the most abundant protein of the procyclic form which is found in the invertebrate host, the tsetse fly vector. Trypanosoma cruzi, on the other hand, expresses a variety of GPI-anchored molecules on their cell surface, such as mucins, that interact with their hosts. The latter is also true for Leishmania, which use GPI anchors to display, amongst others, lipophosphoglycans on their surface. Clearly, GPI-anchoring is a common feature in trypanosomatids and the fact that it has been maintained throughout eukaryote evolution indicates its adaptive value. Here, we explore and discuss GPI anchors as universal evolutionary building blocks that support the great variety of surface molecules of trypanosomatids.
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Affiliation(s)
- Alyssa R Borges
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Fabian Link
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Markus Engstler
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Nicola G Jones
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
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Elmahallawy EK, Alkhaldi AAM. Insights into Leishmania Molecules and Their Potential Contribution to the Virulence of the Parasite. Vet Sci 2021; 8:vetsci8020033. [PMID: 33672776 PMCID: PMC7924612 DOI: 10.3390/vetsci8020033] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/11/2021] [Accepted: 02/14/2021] [Indexed: 12/12/2022] Open
Abstract
Neglected parasitic diseases affect millions of people worldwide, resulting in high morbidity and mortality. Among other parasitic diseases, leishmaniasis remains an important public health problem caused by the protozoa of the genus Leishmania, transmitted by the bite of the female sand fly. The disease has also been linked to tropical and subtropical regions, in addition to being an endemic disease in many areas around the world, including the Mediterranean basin and South America. Although recent years have witnessed marked advances in Leishmania-related research in various directions, many issues have yet to be elucidated. The intention of the present review is to give an overview of the major virulence factors contributing to the pathogenicity of the parasite. We aimed to provide a concise picture of the factors influencing the reaction of the parasite in its host that might help to develop novel chemotherapeutic and vaccine strategies.
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Affiliation(s)
- Ehab Kotb Elmahallawy
- Department of Zoonoses, Faculty of Veterinary Medicine, Sohag University, Sohag 82524, Egypt
- Correspondence: (E.K.E.); (A.A.M.A.)
| | - Abdulsalam A. M. Alkhaldi
- Biology Department, College of Science, Jouf University, Sakaka, Aljouf 2014, Saudi Arabia
- Correspondence: (E.K.E.); (A.A.M.A.)
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6
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Kabiri M, Steverding D. Trypanosoma brucei transferrin receptor: Functional replacement of the GPI anchor with a transmembrane domain. Mol Biochem Parasitol 2021; 242:111361. [PMID: 33450336 DOI: 10.1016/j.molbiopara.2021.111361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 10/22/2022]
Abstract
The transferrin receptor of Trypanosoma brucei (TbTfR) is a heterodimer of a glycosylphosphatidylinositol (GPI)-anchored ESAG6 subunit and an ESAG7 subunit. To investigate whether the GPI-anchor is essential for the function of the TbTfR, an ESAG6 with a transmembrane domain instead of a GPI-anchor (ESAG6tmd) was inducibly expressed in bloodstream form trypanosomes. It is shown that the ESAG6tmd is able to dimerise with ESAG7 to form a TbTfR that can bind transferrin. Fractionation experiments clearly demonstrated that the transmembrane-anchored TbTfR is exclusively associated with the membrane fraction. No difference in the uptake of transferrin was observed between trypanosomes inducibly expressing a transmembrane-anchored TbTfR and trypanosomes inducibly expressing a GPI-anchored TbTfR. Differences in glycosylation pattern of ESAG6tmd and native ESAG6 may indicate different intracellular trafficking of transmembrane- and GPI-anchored TbTfRs. The findings suggest that the GPI-anchor is not essential for the function of the TbTfR in bloodstream forms of T. brucei.
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Affiliation(s)
- Mostafa Kabiri
- Abteilung Parasitologie, Hygiene-Institut der Ruprecht-Karls Universität, Heidelberg, Germany; Sanofi Aventis Deutschland, Translational in Vivo Models, Sanofi Research and Development, Frankfurt, Germany
| | - Dietmar Steverding
- Abteilung Parasitologie, Hygiene-Institut der Ruprecht-Karls Universität, Heidelberg, Germany; Bob Champion Research and Education Centre, Norwich Medical School, University of East Anglia, Norwich, United Kingdom.
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Leishmania donovani Lipophosphoglycan Increases Macrophage-Dependent Chemotaxis of CXCR6-Expressing Cells via CXCL16 Induction. Infect Immun 2019; 87:IAI.00064-19. [PMID: 30804103 DOI: 10.1128/iai.00064-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 02/18/2019] [Indexed: 12/15/2022] Open
Abstract
CXCL16 is a multifunctional chemokine that is highly expressed by macrophages and other immune cells in response to bacterial and viral pathogens; however, little is known regarding the role of CXCL16 during parasitic infections. The protozoan parasite Leishmania donovani is the causative agent of visceral leishmaniasis. Even though chemokine production is a host defense mechanism during infection, subversion of the host chemokine system constitutes a survival strategy adopted by the parasite. Here, we report that L. donovani promastigotes upregulate CXCL16 synthesis and secretion by bone marrow-derived macrophages (BMDM). In contrast to wild-type parasites, a strain deficient in the virulence factor lipophosphoglycan (LPG) failed to induce CXCL16 production. Consistent with this, cell treatment with purified L. donovani LPG augmented CXCL16 expression and secretion. Notably, the ability of BMDM to promote migration of cells expressing CXCR6, the cognate receptor of CXCL16, was augmented upon L. donovani infection in a CXCL16- and LPG-dependent manner. Mechanistically, CXCL16 induction by L. donovani required the activity of AKT and the mechanistic target of rapamycin (mTOR) but was independent of Toll-like receptor signaling. Collectively, these data provide evidence that CXCL16 is part of the inflammatory response elicited by L. donovani LPG in vitro Further investigation using CXCL16 knockout mice is required to determine whether this chemokine contributes to the pathogenesis of visceral leishmaniasis and to elucidate the underlying molecular mechanisms.
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8
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Argueta-Donohué J, Wilkins-Rodríguez AA, Aguirre-García M, Gutiérrez-Kobeh L. Differential phagocytosis of Leishmania mexicana promastigotes and amastigotes by monocyte-derived dendritic cells. Microbiol Immunol 2017; 60:369-81. [PMID: 26399218 DOI: 10.1111/1348-0421.12325] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 09/15/2015] [Accepted: 09/18/2015] [Indexed: 11/28/2022]
Abstract
Leishmania species are dimorphic protozoan parasites that live and replicate in the gut of sand flies as promastigotes or in mammalian hosts as amastigotes. Different immune cells, including DCs, and receptors differ in their involvement in phagocytosis of promastigotes and amastigotes and in recognition of different Leishmania species. In the case of L. mexicana, differences in phagocytosis of promastigotes and amastigotes by DCs and participation of C-type lectin receptors (CLRs) have not been established. In the present study, flow cytometry and confocal microscopy were used to investigate the phagocytosis by monocyte-derived dendritic cells (moDCs) of L. mexicana promastigotes and amastigotes in the presence or absence of immune serum during various periods of time. Blocking antibodies against mannose receptors and DC-SIGN were used to explore the participation of these receptors in the phagocytosis of L. mexicana by moDC. The major differences in interactions of L. mexicana promastigotes and amastigotes with moDC were found to occur within the first 3 hr, during which phagocytosis of promastigotes predominated as compared with opsonization of promastigotes and amastigotes. However, after 6 hr of incubation, opsonized promastigotes were preferentially phagocytosed as compared with unopsonized promastigotes and amastigotes and after 24 hr of incubation there were no differences in the phagocytosis of promastigotes and amastigotes. Finally, after 3 hr incubation, DC-SIGN was involved in the phagocytosis of promastigotes, but not of amastigotes.
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Affiliation(s)
- Jesús Argueta-Donohué
- Experimental Medicine Research Unit, School of Medicine, National Autonomous University of Mexico, Dr. Balmis 148 Col. Doctores, Mexico City 06726, Mexico
| | - Arturo A Wilkins-Rodríguez
- Experimental Medicine Research Unit, School of Medicine, National Autonomous University of Mexico, Dr. Balmis 148 Col. Doctores, Mexico City 06726, Mexico
| | - Magdalena Aguirre-García
- Experimental Medicine Research Unit, School of Medicine, National Autonomous University of Mexico, Dr. Balmis 148 Col. Doctores, Mexico City 06726, Mexico
| | - Laila Gutiérrez-Kobeh
- Experimental Medicine Research Unit, School of Medicine, National Autonomous University of Mexico, Dr. Balmis 148 Col. Doctores, Mexico City 06726, Mexico
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Galdino H, Saar Gomes R, Dos Santos JC, Pessoni LL, Maldaner AE, Marques SM, Gomes CM, Dorta ML, de Oliveira MAP, Joosten LAB, Ribeiro-Dias F. Leishmania (Viannia) braziliensis amastigotes induces the expression of TNFα and IL-10 by human peripheral blood mononuclear cells in vitro in a TLR4-dependent manner. Cytokine 2016; 88:184-192. [PMID: 27649507 DOI: 10.1016/j.cyto.2016.09.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 09/12/2016] [Accepted: 09/14/2016] [Indexed: 11/30/2022]
Abstract
While the role of Toll-like receptors (TLRs) has been investigated in murine models of tegumentary leishmaniasis caused by Leishmania (Viannia) braziliensis, the interaction between TLRs and Leishmania sp. has not been investigated in human cells. The aim of this study was to evaluate the involvement of TLR4 in cytokine production of human peripheral blood mononuclear cells (PBMCs) induced by L. braziliensis, and whether the parasite alters the expression of TLR4 on monocytes/macrophages. Amastigote forms were obtained from mice lesions and PBMCs were isolated from healthy donors. PBMCs were cultured in absence or presence of IFNγ, TLR4 neutralizing antibodies, natural antagonist of TLR4 (Bartonella LPS), TLR4 agonist (E. coli LPS), and amastigote forms. The concentrations of tumor necrosis factor (TNFα) and interleukin 10 (IL-10) were assayed by ELISA and TLR4 expression by flow cytometry. Amastigotes forms of L. braziliensis induced TNFα and IL-10 production only in IFNγ-primed PBMCs. The TNFα and IL-10 production was inhibited by TLR4 neutralization, both with anti-TLR4 antibodies and Bartonella LPS. Interestingly, addition of E. coli LPS further increased TNFα but not IL-10 production induced by L. braziliensis amastigotes. Amastigotes of L. braziliensis strongly reduced membrane TLR4 expression on monocytes/macrophages, apparently by internalization after the infection. The present study reveals that TLR4 drives the production of TNFα and IL-10 induced by L. braziliensis amastigotes and that the parasites decrease TLR4 expression on monocyte surface.
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Affiliation(s)
- Hélio Galdino
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Rodrigo Saar Gomes
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Jessica Cristina Dos Santos
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil; Department of Internal Medicine, Radboud University Medical Center and Radboud Center of Infectious Diseases (RCI), Nijmegen, The Netherlands
| | - Lívia Lara Pessoni
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Anetícia Eduarda Maldaner
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Stéfanne Madalena Marques
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Clayson Moura Gomes
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Miriam Leandro Dorta
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | | | - Leo A B Joosten
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil; Department of Internal Medicine, Radboud University Medical Center and Radboud Center of Infectious Diseases (RCI), Nijmegen, The Netherlands.
| | - Fátima Ribeiro-Dias
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
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10
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Séguin O, Descoteaux A. Leishmania, the phagosome, and host responses: The journey of a parasite. Cell Immunol 2016; 309:1-6. [PMID: 27531526 DOI: 10.1016/j.cellimm.2016.08.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/25/2016] [Accepted: 08/07/2016] [Indexed: 10/21/2022]
Abstract
Leishmania is the eukaryotic parasite responsible for leishmaniases, a spectrum of diseases that puts at risk roughly 350millions of people in 98 countries according to the Drugs for Neglected Diseases initiative (DNDi). This parasite has a complex life cycle composed of two distinct stages, the promastigote form found in the female sand-fly vector and the amastigote form that replicates in the mammalian host (Teixeira et al., 2013) [1]. To survive, the parasite interacts with its host immune system at multiple levels. In this review, we discuss the nature of those interactions, how they affect the host immune system, and how they affect parasite survival from the very beginning of the life cycle in the vector to its dissemination within the mammalian host.
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Affiliation(s)
- Olivier Séguin
- INRS-Institut Armand-Frappier and the Center for Host-Parasite Interactions, Laval, Canada
| | - Albert Descoteaux
- INRS-Institut Armand-Frappier and the Center for Host-Parasite Interactions, Laval, Canada.
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11
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Casgrain PA, Martel C, McMaster WR, Mottram JC, Olivier M, Descoteaux A. Cysteine Peptidase B Regulates Leishmania mexicana Virulence through the Modulation of GP63 Expression. PLoS Pathog 2016; 12:e1005658. [PMID: 27191844 PMCID: PMC4871588 DOI: 10.1371/journal.ppat.1005658] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 05/03/2016] [Indexed: 01/30/2023] Open
Abstract
Cysteine peptidases play a central role in the biology of Leishmania. In this work, we sought to further elucidate the mechanism(s) by which the cysteine peptidase CPB contributes to L. mexicana virulence and whether CPB participates in the formation of large communal parasitophorous vacuoles induced by these parasites. We initially examined the impact of L. mexicana infection on the trafficking of VAMP3 and VAMP8, two endocytic SNARE proteins associated with phagolysosome biogenesis and function. Using a CPB-deficient mutant, we found that both VAMP3 and VAMP8 were down-modulated in a CPB-dependent manner. We also discovered that expression of the virulence-associated GPI-anchored metalloprotease GP63 was inhibited in the absence of CPB. Expression of GP63 in the CPB-deficient mutant was sufficient to down-modulate VAMP3 and VAMP8. Similarly, episomal expression of GP63 enabled the CPB-deficient mutant to establish infection in macrophages, induce the formation of large communal parasitophorous vacuoles, and cause lesions in mice. These findings implicate CPB in the regulation of GP63 expression and provide evidence that both GP63 and CPB are key virulence factors in L. mexicana. The parasite Leishmania mexicana expresses several cysteine peptidases of the papain family that are involved in processes such as virulence and evasion of host immune responses. The cysteine peptidase CPB is required for survival within macrophages and for lesion formation in susceptible mice. Upon their internalization by macrophages, parasites of the L. mexicana complex induce the formation of large communal parasitophorous vacuoles in which they replicate, and expansion of those large vacuoles correlates with the ability of the parasites to survive inside macrophages. Here, we found that CPB contributes to L. mexicana virulence (macrophage survival, formation and expansion of communal parasitophorous vacuoles, lesion formation in mice) through the regulation of the virulence factor GP63, a Leishmania zinc-metalloprotease that acts by cleaving key host cell proteins. This work thus elucidates a novel Leishmania virulence regulatory mechanism whereby CPB controls the expression of GP63.
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Affiliation(s)
- Pierre-André Casgrain
- INRS- Institut Armand-Frappier and the Center for Host-Parasite Interactions, Laval, Canada
| | - Caroline Martel
- The Research Institute of the McGill University Health Centre, Montréal, Canada
| | - W. Robert McMaster
- Immunity and Infection Research Centre, Vancouver Coastal Health Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Jeremy C. Mottram
- Centre for Immunology and Infection, Department of Biology, University of York, Wentworth Way Heslington, York, United Kingdom
| | - Martin Olivier
- The Research Institute of the McGill University Health Centre, Montréal, Canada
| | - Albert Descoteaux
- INRS- Institut Armand-Frappier and the Center for Host-Parasite Interactions, Laval, Canada
- * E-mail:
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Cabezas Y, Legentil L, Robert-Gangneux F, Daligault F, Belaz S, Nugier-Chauvin C, Tranchimand S, Tellier C, Gangneux JP, Ferrières V. Leishmania cell wall as a potent target for antiparasitic drugs. A focus on the glycoconjugates. Org Biomol Chem 2016; 13:8393-404. [PMID: 26130402 DOI: 10.1039/c5ob00563a] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Although leishmaniasis has been studied for over a century, the fight against cutaneous, mucocutaneous and visceral forms of the disease remains a hot topic. This review refers to the parasitic cell wall and more particularly to the constitutive glycoconjugates. The structures of the main glycolipids and glycoproteins, which are species-dependent, are described. The focus is on the disturbance of the lipid membrane by existing drugs and possible new ones, in order to develop future therapeutic agents.
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Affiliation(s)
- Yari Cabezas
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France.
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13
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Differential Impact of LPG-and PG-Deficient Leishmania major Mutants on the Immune Response of Human Dendritic Cells. PLoS Negl Trop Dis 2015; 9:e0004238. [PMID: 26630499 PMCID: PMC4667916 DOI: 10.1371/journal.pntd.0004238] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 10/25/2015] [Indexed: 11/30/2022] Open
Abstract
Background Leishmania major infection induces robust interleukin-12 (IL12) production in human dendritic cells (hDC), ultimately resulting in Th1-mediated immunity and clinical resolution. The surface of Leishmania parasites is covered in a dense glycocalyx consisting of primarily lipophosphoglycan (LPG) and other phosphoglycan-containing molecules (PGs), making these glycoconjugates the likely pathogen-associated molecular patterns (PAMPS) responsible for IL12 induction. Methodology/Principal Findings Here we explored the role of parasite glycoconjugates on the hDC IL12 response by generating L. major Friedlin V1 mutants defective in LPG alone, (FV1 lpg1-), or generally deficient for all PGs, (FV1 lpg2-). Infection with metacyclic, infective stage, L. major or purified LPG induced high levels of IL12B subunit gene transcripts in hDCs, which was abrogated with FV1 lpg1- infections. In contrast, hDC infections with FV1 lpg2- displayed increased IL12B expression, suggesting other PG-related/LPG2 dependent molecules may act to dampen the immune response. Global transcriptional profiling comparing WT, FV1 lpg1-, FV1 lpg2- infections revealed that FV1 lpg1- mutants entered hDCs in a silent fashion as indicated by repression of gene expression. Transcription factor binding site analysis suggests that LPG recognition by hDCs induces IL-12 in a signaling cascade resulting in Nuclear Factor κ B (NFκB) and Interferon Regulatory Factor (IRF) mediated transcription. Conclusions/Significance These data suggest that L. major LPG is a major PAMP recognized by hDC to induce IL12-mediated protective immunity and that there is a complex interplay between PG-baring Leishmania surface glycoconjugates that result in modulation of host cellular IL12. Leishmaniasis is a group of parasitic diseases caused by intracellular protozoa belonging to the genus Leishmania, pathological manifestations ranging from self-healing cutaneous forms to severe visceral infections that result in death. These clinical outcomes are dictated by the Leishmania species initiating the infection and are influenced by early responses of host immune cells, which ultimately initiate an IL12 mediated immune response in resolving infections. Like the diseases themselves, the magnitude of IL12 induction in hDCs is Leishmania-species and strain specific, where species that elicit visceral disease do not induce IL12, while most cutaneous disease-causing L. major strains induce robust IL12 responses and confer life-long immunity. The molecular mechanisms that mediate the ability of these innate immune cells to discriminate between pathogens remain elusive and have been primarily investigated in murine model systems. Here we identified L. major LPG as a major PAMP that induces IL12 in hDCs. Elucidation of this critical component of human immunity to L. major has ramifications for leishmaniasis vaccine development.
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Abstract
Leishmania amazonensis is an intracellular protozoan parasite responsible for chronic cutaneous leishmaniasis (CL). CL is a neglected tropical disease responsible for infecting millions of people worldwide. L. amazonensis promotes alteration of various signaling pathways that are essential for host cell survival. Specifically, through parasite-mediated phosphorylation of extracellular signal regulated kinase (ERK), L. amazonensis inhibits cell-mediated parasite killing and promotes its own survival by co-opting multiple host cell functions. In this review, we highlight Leishmania-host cell signaling alterations focusing on those specific to (1) motor proteins, (2) prevention of NADPH subunit phosphorylation impairing reactive oxygen species production, and (3) localized endosomal signaling to up-regulate ERK phosphorylation. This review will focus upon mechanisms and possible explanations as to how Leishmania spp. evades the various layers of defense employed by the host immune response.
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Eggimann GA, Sweeney K, Bolt HL, Rozatian N, Cobb SL, Denny PW. The role of phosphoglycans in the susceptibility of Leishmania mexicana to the temporin family of anti-microbial peptides. Molecules 2015; 20:2775-85. [PMID: 25668079 PMCID: PMC6272152 DOI: 10.3390/molecules20022775] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 01/28/2015] [Indexed: 11/20/2022] Open
Abstract
Natural product antimicrobial peptides (AMPs) have been proposed as promising agents against the Leishmania species, insect vector borne protozoan parasites causing the neglected tropical disease leishmaniasis. However, recent studies have shown that the mammalian pathogenic amastigote form of L. mexicana, a causative agent of cutaneous leishmaniasis, is resistant to the amphibian-derived temporin family of AMPs when compared to the insect stage promastigote form. The mode of resistance is unknown, however the insect and mammalian stages of Leishmania possess radically different cell surface coats, with amastigotes displaying low (or zero) quantities of lipophosphoglycan (LPG) and proteophosphoglycan (PPG), macromolecules which form thick a glycocalyx in promastigotes. It has been predicted that negatively charged LPG and PPG influence the sensitivity/resistance of promastigote forms to cationic temporins. Using LPG and PPG mutant L. mexicana, and an extended range of temporins, in this study we demonstrated that whilst LPG has little role, PPG is a major factor in promastigote sensitivity to the temporin family of AMPs, possibly due to the conferred anionic charge. Therefore, the lack of PPG seen on the surface of pathogenic amastigote L. mexicana may be implicated in their resistance to these peptides.
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Affiliation(s)
- Gabriela A Eggimann
- Biophysical Sciences Institute, Department of Chemistry and School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK.
| | - Kathryn Sweeney
- Biophysical Sciences Institute, Department of Chemistry and School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK.
| | - Hannah L Bolt
- Biophysical Sciences Institute, Department of Chemistry and School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK.
| | - Neshat Rozatian
- Biophysical Sciences Institute, Department of Chemistry and School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK.
| | - Steven L Cobb
- Biophysical Sciences Institute, Department of Chemistry and School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK.
| | - Paul W Denny
- Biophysical Sciences Institute, Department of Chemistry and School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK.
- School of Medicine, Pharmacy and Health, Durham University, Queen's Campus, Stockton-on-Tees TS17 6BH, UK.
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Forestier CL, Gao Q, Boons GJ. Leishmania lipophosphoglycan: how to establish structure-activity relationships for this highly complex and multifunctional glycoconjugate? Front Cell Infect Microbiol 2015; 4:193. [PMID: 25653924 PMCID: PMC4301024 DOI: 10.3389/fcimb.2014.00193] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 12/22/2014] [Indexed: 01/09/2023] Open
Abstract
A key feature of many pathogenic microorganisms is the presence of a dense glycocalyx at their surface, composed of lipid-anchored glycoproteins and non-protein-bound polysaccharides. These surface glycolipids are important virulence factors for bacterial, fungal and protozoan pathogens. The highly complex glycoconjugate lipophosphoglycan (LPG) is one of the dominant surface macromolecules of the promastigote stage of all Leishmania parasitic species. LPG plays critical pleiotropic roles in parasite survival and infectivity in both the sandfly vector and the mammalian host. Here, we review the composition of the Leishmania glycocalyx, the chemical structure of LPG and what is currently known about its effects in the mammalian host, specifically. We will then discuss the current approaches employed to elucidate LPG functions. Finally, we will provide a viewpoint on future directions that this area of investigation could take to unravel in detail the biological activity of the specific molecular elements composing the structurally complex LPG.
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Affiliation(s)
| | - Qi Gao
- Complex Carbohydrate Research Center, Department of Chemistry, University of Georgia Athens, GA, USA
| | - Geert-Jan Boons
- Complex Carbohydrate Research Center, Department of Chemistry, University of Georgia Athens, GA, USA
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Phillips MR, Turco SJ. Characterization of a ricin-resistant mutant of Leishmania donovani that expresses lipophosphoglycan. Glycobiology 2014; 25:428-37. [PMID: 25472443 DOI: 10.1093/glycob/cwu130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The abundant cell-surface lipophosphoglycan (LPG) of Leishmania parasites plays a central role throughout the eukaryote's life cycle. A number of LPG-defective mutants and their complementing genes have been isolated and have proven invaluable in assessing the importance of LPG and related glycoconjugates in parasite virulence. While ricin agglutination selection protocols frequently result in lpg- mutants, one Leishmania donovani variant we isolated, named JABBA, was found to be lpg+. Procyclic (logarithmic) JABBA expresses significant amounts of a large-sized LPG, larger than observed from procyclic wild type but similar in size to LPG from wild type from metacyclic (stationary) phase. Structural analysis of the LPG from logarithmically grown JABBA by capillary electrophoresis protocols revealed that it averaged 30 repeat units composed of the unsubstituted Gal(β1,4)Man(α1)-PO4 typical of wild-type L. donovani. Analysis of JABBA LPG caps indicated that 20% is branched trisaccharide Gal(β1,4)[Glc(β1,2)]Man and tetrasaccharide Gal(β1,4)[Glc(β1,2)Man(α1,2)]Man instead of the usual Gal(β1,4)Man and Man(α1,2)Man terminating caps. Consistent with these structural observations, analyses of the relevant glycosyltransferases in JABBA microsomes involved in LPG biosynthesis showed a 2-fold increase in elongating mannosylphosphoryltransferase activity and up-regulation of a β-glucosyltransferase activity. Furthermore, the caps of JABBA LPG are cryptic in presentation as shown by the loss of binding by the lectins, ricin, peanut agglutinin and concanavalin A and reduced accessibility of the terminal galactose residues to oxidation by galactose oxidase. These results indicate that LPG from JABBA is intriguingly similar to the larger LPG in wild-type parasites that arises following the differentiation of the non-infectious procyclic promastigotes to infectious, metacyclic forms.
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Affiliation(s)
- Megan R Phillips
- Department of Biochemistry, University of Kentucky Medical Center, Lexington, KY 40536, USA
| | - Salvatore J Turco
- Department of Biochemistry, University of Kentucky Medical Center, Lexington, KY 40536, USA
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Price HP, Paape D, Hodgkinson MR, Farrant K, Doehl J, Stark M, Smith DF. The Leishmania major BBSome subunit BBS1 is essential for parasite virulence in the mammalian host. Mol Microbiol 2013; 90:597-611. [PMID: 23998526 PMCID: PMC3916885 DOI: 10.1111/mmi.12383] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2013] [Indexed: 12/17/2022]
Abstract
Bardet-Biedl syndrome (BBS) is a human genetic disorder with a spectrum of symptoms caused by primary cilium dysfunction. The disease is caused by mutations in one of at least 17 identified genes, of which seven encode subunits of the BBSome, a protein complex required for specific trafficking events to and from the primary cilium. The molecular mechanisms associated with BBSome function remain to be fully elucidated. Here, we generated null and complemented mutants of the BBSome subunit BBS1 in the protozoan parasite, Leishmania. In the absence of BBS1, extracellular parasites have no apparent defects in growth, flagellum assembly, motility or differentiation in vitro but there is accumulation of vacuole-like structures close to the flagellar pocket. Infectivity of these parasites for macrophages in vitro is reduced compared with wild-type controls but the null parasites retain the ability to differentiate to the intracellular amastigote stage. However, infectivity of BBS1 null parasites is severely compromised in a BALB/c mouse footpad model. We hypothesize that the absence of BBS1 in Leishmania leads to defects in specific trafficking events that affect parasite persistence in the host. This is the first report of an association between the BBSome complex and pathogen infectivity.
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Affiliation(s)
- Helen P Price
- Centre for Immunology and Infection, Department of Biology, University of York, Heslington, York, YO10 5YW, UK
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Innate immune activation and subversion of Mammalian functions by leishmania lipophosphoglycan. J Parasitol Res 2012; 2012:165126. [PMID: 22523640 PMCID: PMC3317186 DOI: 10.1155/2012/165126] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 11/10/2011] [Indexed: 12/19/2022] Open
Abstract
Leishmania promastigotes express several prominent glycoconjugates, either secreted or anchored to the parasite surface. Of these lipophosphoglycan (LPG) is the most abundant, and along with other phosphoglycan-bearing molecules, plays important roles in parasite infectivity and pathogenesis in both the sand fly and the mammalian host. Besides its contribution for parasite survival in the sand fly vector, LPG is important for modulation the host immune responses to favor the establishment of mammalian infection. This review will summarize the current knowledge regarding the role of LPG in Leishmania infectivity, focusing on the interaction of LPG and innate immune cells and in the subversion of mammalian functions by this molecule.
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de Assis RR, Ibraim IC, Nogueira PM, Soares RP, Turco SJ. Glycoconjugates in New World species of Leishmania: polymorphisms in lipophosphoglycan and glycoinositolphospholipids and interaction with hosts. Biochim Biophys Acta Gen Subj 2011; 1820:1354-65. [PMID: 22093608 DOI: 10.1016/j.bbagen.2011.11.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 10/31/2011] [Accepted: 11/01/2011] [Indexed: 11/29/2022]
Abstract
BACKGROUND Protozoan parasites of the genus Leishmania cause a number of important diseases in humans and undergo a complex life cycle, alternating between a sand fly vector and vertebrate hosts. The parasites have a remarkable capacity to avoid destruction in which surface molecules are determinant for survival. Amongst the many surface molecules of Leishmania, the glycoconjugates are known to play a central role in host-parasite interactions and are the focus of this review. SCOPE OF THE REVIEW The most abundant and best studied glycoconjugates are the Lipophosphoglycans (LPGs) and glycoinositolphospholipids (GIPLs). This review summarizes the main studies on structure and biological functions of these molecules in New World Leishmania species. MAJOR CONCLUSIONS LPG and GIPLs are complex molecules that display inter- and intraspecies polymorphisms. They are key elements for survival inside the vector and to modulate the vertebrate immune response during infection. GENERAL SIGNIFICANCE Most of the studies on glycoconjugates focused on Old World Leishmania species. Here, it is reported some of the studies involving New World species and their biological significance on host-parasite interaction. This article is part of a Special Issue entitled Glycoproteomics.
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Affiliation(s)
- Rafael Ramiro de Assis
- Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, FIOCRUZ, Av. Augusto de Lima, 1715, Belo Horizonte, MG 30190-002, Brazil
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Kulkarni MM, Barbi J, McMaster WR, Gallo RL, Satoskar AR, McGwire BS. Mammalian antimicrobial peptide influences control of cutaneous Leishmania infection. Cell Microbiol 2011; 13:913-23. [PMID: 21501359 DOI: 10.1111/j.1462-5822.2011.01589.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cathelicidin-type antimicrobial peptides (CAMP) are important mediators of innate immunity against microbial pathogens acting through direct interaction with and disruption of microbial membranes and indirectly through modulation of host cell migration and activation. Using a mouse knock-out model in CAMP we studied the role of this host peptide in control of dissemination of cutaneous infection by the parasitic protozoan Leishmania. The presence of pronounced host inflammatory infiltration in lesions and lymph nodes of infected animals was CAMP-dependent. Lack of CAMP expression was associated with higher levels of IL-10 receptor expression in bone marrow, splenic and lymph node macrophages as well as higher anti-inflammatory IL-10 production by bone marrow macrophages and spleen cells but reduced production of the pro-inflammatory cytokines IL-12 and IFN-γ by lymph nodes. Unlike wild-type mice, local lesions were exacerbated and parasites were found largely disseminated in CAMP knockouts. Infection of CAMP knockouts with parasite mutants lacking the surface metalloprotease virulence determinant resulted in more robust disseminated infection than in control animals suggesting that CAMP activity is negatively regulated by parasite surface proteolytic activity. This correlated with the ability of the protease to degrade CAMP in vitro and co-localization of CAMP with parasites within macrophages. Our results highlight the interplay of antimicrobial peptides and Leishmania that influence the host immune response and the outcome of infection.
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Affiliation(s)
- Manjusha M Kulkarni
- Center for Microbial Interface Biology, The Ohio State University Medical Center, Columbus, OH, USA
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Differential microbicidal effects of human histone proteins H2A and H2B on Leishmania promastigotes and amastigotes. Infect Immun 2010; 79:1124-33. [PMID: 21189319 DOI: 10.1128/iai.00658-10] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent studies have shown that histone proteins can act as antimicrobial peptides in host defense against extracellular bacteria, fungi, and Leishmania promastigotes. In this study, we used human recombinant histone proteins to further study their leishmaniacidal effects and the underlying mechanisms. We found that the histones H2A and H2B (but not H1(0)) could directly and efficiently kill promastigotes of Leishmania amazonensis, L. major, L. braziliensis, and L. mexicana in a treatment dose-dependent manner. Scanning electron microscopy revealed surface disruption of histone-treated promastigotes. More importantly, the preexposure of promastigotes to histone proteins markedly decreased the infectivity of promastigotes to murine macrophages (Mφs) in vitro. However, axenic and lesion-derived amastigotes of L. amazonensis and L. mexicana were relatively resistant to histone treatment, which correlated with the low levels of intracellular H2A in treated amastigotes. To understand the mechanisms underlying these differential responses, we investigated the role of promastigote surface molecules in histone-mediated killing. Compared with the corresponding controls, transgenic L. amazonensis promastigotes expressing lower levels of surface gp63 proteins were more susceptible to histone H2A, while L. major and L. mexicana promastigotes with targeted deletion of the lipophosphoglycan 2 (lpg2) gene (but not the lpg1 gene) were more resistant to histone H2A. We discuss the influence of promastigote major surface molecules in the leishmaniacidal effect of histone proteins. This study provides new information on host innate immunity to different developmental stages of Leishmania parasites.
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Passero LFD, Da Costa Bordon MLA, De Carvalho AK, Martins LM, Corbett CEP, Laurenti MD. Exacerbation of Leishmania (Viannia) shawi infection in BALB/c mice after immunization with soluble antigen from amastigote forms. APMIS 2010; 118:973-81. [PMID: 21091779 DOI: 10.1111/j.1600-0463.2010.02679.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The present study aimed to evaluate the effects of immunization with soluble amastigote (AmaAg) and promastigote (ProAg) antigens from Leishmania (Viannia) shawi on the course of infection in BALB/c mice. After immunization with AmaAg, the challenged group showed greater lesion size and parasite load in the skin and lymph nodes, associated with diminished interleukin (IL)-2, IL-4, IL-10, interferon (IFN)-γ and nitrate levels in the supernatant of lymph node cell cultures, together with increases in transforming growth factor (TGF)-β concentrations and humoral immune response. In contrast, immunization with ProAg led to smaller lesion size with reduced numbers of viable parasites in the skin. Protection was associated with increases in IL-12, IFN-γ, TGF-β and nitrates and decreases in IL-4 and IL-10 levels. Concerning humoral immune response, a significant reduction in anti-leishmania immunoglobulin G was verified in the ProAg-challenged group. Analysis of these results suggests that AmaAg induced a suppressive cellular immune response in mice, favouring the spread of infection, whereas ProAg induced partial protection associated with increased cellular immune response.
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Lamerz AC, Damerow S, Kleczka B, Wiese M, van Zandbergen G, Lamerz J, Wenzel A, Hsu FF, Turk J, Beverley SM, Routier FH. Deletion of UDP-glucose pyrophosphorylase reveals a UDP-glucose independent UDP-galactose salvage pathway in Leishmania major. Glycobiology 2010; 20:872-82. [PMID: 20335578 DOI: 10.1093/glycob/cwq045] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The nucleotide sugar UDP-galactose (UDP-Gal) is essential for the biosynthesis of several abundant glycoconjugates forming the surface glycocalyx of the protozoan parasite Leishmania major. Current data suggest that UDP-Gal could arise de novo by epimerization of UDP-glucose (UDP-Glc) or by a salvage pathway involving phosphorylation of Gal and the action of UDP-glucose:alpha-D-galactose-1-phosphate uridylyltransferase as described by Leloir. Since both pathways require UDP-Glc, inactivation of the UDP-glucose pyrophosphorylase (UGP) catalyzing activation of glucose-1 phosphate to UDP-Glc was expected to deprive parasites of UDP-Gal required for Leishmania glycocalyx formation. Targeted deletion of the gene encoding UGP, however, only partially affected the synthesis of the Gal-rich phosphoglycans. Moreover, no alteration in the abundant Gal-containing glycoinositolphospholipids was found in the deletion mutant. Consistent with these findings, the virulence of the UGP-deficient mutant was only modestly affected. These data suggest that Leishmania elaborates a UDP-Glc independent salvage pathway for UDP-Gal biosynthesis.
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Abstract
Major surface protease (MSP or GP63) is the most abundant glycoprotein localized to the plasma membrane of Leishmania promastigotes. MSP plays several important roles in the pathogenesis of leishmaniasis, including but not limited to (i) evasion of complement-mediated lysis, (ii) facilitation of macrophage (Mø) phagocytosis of promastigotes, (iii) interaction with the extracellular matrix, (iv) inhibition of natural killer cellular functions, (v) resistance to antimicrobial peptide killing, (vi) degradation of Mø and fibroblast cytosolic proteins, and (vii) promotion of survival of intracellular amastigotes. MSP homologues have been found in all other trypanosomatids studied to date including heteroxenous members of Trypanosoma cruzi, the extracellular Trypanosoma brucei, unusual intraerythrocytic Endotrypanum spp., phytoparasitic Phytomonas spp., and numerous monoxenous species. These proteins are likely to perform roles different from those described for Leishmania spp. Multiple MSPs in individual cells may play distinct roles at some time points in trypanosomatid life cycles and collaborative or redundant roles at others. The cellular locations and the extracellular release of MSPs are also discussed in connection with MSP functions in leishmanial promastigotes.
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Rivas L, Luque-Ortega JR, Andreu D. Amphibian antimicrobial peptides and Protozoa: Lessons from parasites. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1570-81. [DOI: 10.1016/j.bbamem.2008.11.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 10/29/2008] [Accepted: 11/03/2008] [Indexed: 02/06/2023]
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Field MC, Lumb JH, Adung'a VO, Jones NG, Engstler M. Chapter 1 Macromolecular Trafficking and Immune Evasion in African Trypanosomes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 278:1-67. [DOI: 10.1016/s1937-6448(09)78001-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Nebohácová M, Kim CE, Simpson L, Maslov DA. RNA editing and mitochondrial activity in promastigotes and amastigotes of Leishmania donovani. Int J Parasitol 2008; 39:635-44. [PMID: 19109964 DOI: 10.1016/j.ijpara.2008.10.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 10/29/2008] [Accepted: 10/30/2008] [Indexed: 11/30/2022]
Abstract
Kinetoplast maxicircle DNA sequence organisation was investigated in Leishmania donovani, strain 1S LdBob. Gene arrangement in the coding (conserved) region of the maxicircle is collinear with that of most trypanosomatids, with individual genes showing 80-90% nucleotide identity to Leishmania tarentolae, strain UC. The notable exception was an integration of a full-size minicircle sequence in the ND1 gene coding region found in L. donovani. Editing patterns of the mitochondrial mRNAs investigated also followed L. tarentolae UC patterns, including productive editing of the components of respiratory complexes III-V, and ribosomal protein S12 (RPS12), as well as the lack of productive editing in five out of six pan-edited cryptogenes (ND3, ND8, ND9, G3, G4) found in these species. Several guide RNAs for the editing events were localised in minicircles and maxicircles in the locations that are conserved between the species. Mitochondrial activity, including rates of oxygen consumption, the presence and the levels of respiratory complexes and their individual subunits and the steady-state levels of several mitochondrial-encoded mRNAs were essentially the same in axenically grown amastigotes and in promastigotes of L. donovani. However, some modulation of mitochondrial activity between these developmental stages was suggested by the finding of an amastigote-specific component in complex IV, a down-regulation of mitochondrial RNA-binding proteins (MRP) and MRP-associated protein (MRP-AP) in amastigotes, and by variations in the levels of RPS12, ND3, ND9, G3 and G4 pre-edited transcripts.
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Affiliation(s)
- Martina Nebohácová
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
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Lippuner C, Paape D, Paterou A, Brand J, Richardson M, Smith AJ, Hoffmann K, Brinkmann V, Blackburn C, Aebischer T. Real‐time imaging ofLeishmania mexicana‐infected early phagosomes: a study using primary macrophages generated from green fluorescent protein‐Rab5 transgenic mice. FASEB J 2008; 23:483-91. [DOI: 10.1096/fj.08-108712] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Christoph Lippuner
- Department of Molecular BiologyMax‐Planck‐Institute for Infection BiologyBerlinGermany
- Institut für Pharmazeutische Wissenschaften, Pharmazeutische Biologie und BiotechnologieAlbert‐Ludwigs‐Universität FreiburgGermany
| | - Daniel Paape
- Department of Molecular BiologyMax‐Planck‐Institute for Infection BiologyBerlinGermany
- Marie Curie Team Pathogen Habitats, Institute of Immunology and Infection ResearchUniversity of Edinburgh, EdinburghUK
| | - Athina Paterou
- Marie Curie Team Pathogen Habitats, Institute of Immunology and Infection ResearchUniversity of Edinburgh, EdinburghUK
| | - Janko Brand
- Department of Molecular BiologyMax‐Planck‐Institute for Infection BiologyBerlinGermany
| | | | - Andrew J. Smith
- Institute for Stem Cell ResearchUniversity of EdinburghEdinburghUK
| | - Kirstin Hoffmann
- Department of Molecular BiologyMax‐Planck‐Institute for Infection BiologyBerlinGermany
| | - Volker Brinkmann
- Central Microscopy UnitMax‐Planck‐Institute for Infection BiologyBerlinGermany
| | - Clare Blackburn
- Institute for Stem Cell ResearchUniversity of EdinburghEdinburghUK
| | - Toni Aebischer
- Department of Molecular BiologyMax‐Planck‐Institute for Infection BiologyBerlinGermany
- Marie Curie Team Pathogen Habitats, Institute of Immunology and Infection ResearchUniversity of Edinburgh, EdinburghUK
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31
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Morales MA, Watanabe R, Laurent C, Lenormand P, Rousselle JC, Namane A, Späth GF. Phosphoproteomic analysis of Leishmania donovani pro- and amastigote stages. Proteomics 2008; 8:350-63. [PMID: 18203260 DOI: 10.1002/pmic.200700697] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Following transmission to the vertebrate host, the protozoan parasite Leishmania donovani differentiates into the pathogenic amastigote stage that is adapted for intracellular survival. This developmental transition is induced by environmental factors including elevated temperature and acidic pH and is likely transduced by signaling cascades involving protein kinases and their downstream phosphoprotein substrates. These signaling networks are highly adapted to the specific nutritional and physiological requirements of the organism and thus studying Leishmania phosphorylation may allow important insight into the parasite-specific biology. We used a gel-based approach to investigate qualitative and quantitative changes of the phosphoproteome of the major L. donovani life cycle stages. Phosphoproteins were purified by immobilized metal affinity chromatography (IMAC), separated by IEF and SDS-PAGE using pH 4-7 IPG immobiline strips, revealed by fluorescent multiplex staining, and identified by MALDI-MS and MS/MS. Our analysis allowed us to establish a first repertoire of the Leishmania phosphoproteome and to identify phosphoproteins implicated in stress- and heat shock response, RNA/protein turnover, metabolism, and signaling.
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Affiliation(s)
- Miguel A Morales
- Department of Parasitology and Mycology, Laboratory of Parasite Virulence, Institut Pasteur, 25-28 rue du Dr. Roux, Paris Cedex 15, France
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Chiovitti A, Heraud P, Dugdale TM, Hodson OM, Curtain RCA, Dagastine RR, Wood BR, Wetherbee R. Divalent cations stabilize the aggregation of sulfated in the adhesive nanofibers of the biofouling diatom Toxarium undulatum. SOFT MATTER 2008; 4:811-820. [PMID: 32907187 DOI: 10.1039/b715455k] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A species of marine diatom, Toxarium undulatum, has emerged as a problematic biofouler of contemporary environmentally benign marine coatings. Previous analyses by atomic force microscopy (AFM) showed the cell-substratum adhesive of this alga contained macromolecules with a modular protein backbone assembled into nanofibers in which the domains of the macromolecules folded and unfolded in a co-ordinated manner. In the present study, we investigated further the composition and properties of the adhesive. A combination of energy dispersive X-ray analysis (EDXA) and Fourier transform infrared (FTIR) spectroscopy showed that the adhesive contained mainly protein, carbohydrate, sulfate, calcium, and magnesium. AFM demonstrated that EDTA treatment of native T. undulatum adhesive resulted in rapid disruption of the adhesive nanofiber (ANF) structure but ANFs were restored by subsequent treatment (within 1 h) with solutions containing divalent cations. Prolonged exposure to EDTA (≥18 h) led to cell detachment. The soluble EDTA extract was separated from the cells, dialyzed, concentrated, and analyzed further. The extract had a protein-to-carbohydrate-to-sulfate weight ratio of 1.0 : 0.2 : 0.9 and contained a single, high-molecular-mass (>220 kDa) band by SDS-PAGE which was visualized by Stains-All® but not by Coomassie blue, indicating that it was a highly anionic macromolecule. The most abundant amino acids in the extract were glycine (22 mol%), aspartic acid/aspartamine (14 mol%), and histidine (11 mol%). The adhesive contained 11 neutral sugars dominated by mannose (50 mol%) and xylose (29 mol%). On the basis of these data, we propose that the ANFs of T. undulatum are composed of sulfated high-molecular-mass glycoproteins cross-linked by calcium and magnesium ions. The cross-linking enables domains of adjacent protein backbones to unfold and re-fold in register.
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Affiliation(s)
- Anthony Chiovitti
- School of Botany, University of Melbourne, Victoria 3010, Australia.
| | - Philip Heraud
- Centre for Biospectroscopy, Monash University, Clayton, Victoria 3800, Australia
| | - Tony M Dugdale
- School of Botany, University of Melbourne, Victoria 3010, Australia.
| | - Oliver M Hodson
- School of Botany, University of Melbourne, Victoria 3010, Australia.
| | - Roger C A Curtain
- Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria 3010, Australia
| | - Raymond R Dagastine
- Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria 3010, Australia and Particulate Fluids Processing Centre, University of Melbourne, Victoria 3010, Australia
| | - Bayden R Wood
- Centre for Biospectroscopy, Monash University, Clayton, Victoria 3800, Australia
| | - Richard Wetherbee
- School of Botany, University of Melbourne, Victoria 3010, Australia.
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Hsiao CHC, Yao C, Storlie P, Donelson JE, Wilson ME. The major surface protease (MSP or GP63) in the intracellular amastigote stage of Leishmania chagasi. Mol Biochem Parasitol 2007; 157:148-59. [PMID: 18067978 DOI: 10.1016/j.molbiopara.2007.10.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 10/16/2007] [Accepted: 10/23/2007] [Indexed: 10/22/2022]
Abstract
The Leishmania spp. protozoa have an abundant surface metalloprotease called MSP (major surface protease), which in Leishmania chagasi is encoded by three distinct gene classes (MSPS, MSPL, MSPC). Although MSP has been characterized primarily in extracellular promastigotes, it also facilitates survival of intracellular amastigotes. Promastigotes express MSPS, MSPL, and two forms of MSPC RNAs, whereas amastigotes express only MSPL RNA and one MSPC transcript. We confirmed the presence of MSPC protein in both promastigotes and amastigotes by liquid chromatography-tandem mass spectrometry (LC-MS/MS). More than 10 MSP isoforms were visualized in both amastigotes and promastigotes using two-dimensional immunoblots, but amastigote MSPs migrated at a more acidic pI. Promastigote MSPs were N-glycosylated, whereas most amastigote MSPs were not. Immuno-electron microscopy showed that two-thirds of the promastigote MSP is distributed along the cell surface. In contrast, most amastigote MSP localized at the flagellar pocket, the major site of leishmania endocytosis/exocytosis. Biochemical analyses indicated that most amastigote MSP is soluble in the cytosol, vesicles or organelles, whereas most promastigote MSP is membrane-associated and GPI anchored. Activity gels and immunoblots confirmed the presence of a novel proteolytically active amastigote MSP of higher Mr than the promastigote MSPs. Furthermore, promastigote MSP is shed extracellularly whereas MSP is not shed from axenic amastigotes. We conclude that amastigotes and promastigotes both express multiple MSP isoforms, but these MSPs differ biochemically and localize differently in the two parasite stages. We hypothesize that MSP plays different roles in the extracellular versus intracellular forms of Leishmania spp.
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Yao C, Donelson JE, Wilson ME. Internal and surface-localized major surface proteases of Leishmania spp. and their differential release from promastigotes. EUKARYOTIC CELL 2007; 6:1905-12. [PMID: 17693594 PMCID: PMC2043387 DOI: 10.1128/ec.00073-07] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Major surface protease (MSP), also called GP63, is a virulence factor of Leishmania spp. protozoa. There are three pools of MSP, located either internally within the parasite, anchored to the surface membrane, or released into the extracellular environment. The regulation and biological functions of these MSP pools are unknown. We investigated here the trafficking and extrusion of surface versus internal MSPs. Virulent Leishmania chagasi undergo a growth-associated lengthening in the t(1/2) of surface-localized MSP, but this did not occur in the attenuated L5 strain. The release of surface-localized MSP was enhanced in a dose-dependent manner by MbetaCD, which chelates membrane cholesterol-ergosterol. Furthermore, incubation of promastigotes at 37 degrees C with Matrigel matrix, a soluble basement membrane extract of Engelbreth-Holm-Swarm tumor cells, stimulated the release of internal MSP but not of surface-located MSP. Taken together, these data indicate that MSP subpopulations in distinct cellular locations are released from the parasite under different environmental conditions. We hypothesize that the internal MSP with its lengthy t(1/2) does not serve as a pool for promastigote surface MSP in the sand fly vector but that it instead functions as an MSP pool ready for quick release upon inoculation of metacyclic promastigotes into mammals. We present a model in which these different MSP pools are released under distinct life cycle-specific conditions.
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Affiliation(s)
- Chaoqun Yao
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA.
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35
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Santos ALS, Branquinha MH, D'Avila-Levy CM. The ubiquitous gp63-like metalloprotease from lower trypanosomatids: in the search for a function. AN ACAD BRAS CIENC 2006; 78:687-714. [PMID: 17143406 DOI: 10.1590/s0001-37652006000400006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Accepted: 02/15/2006] [Indexed: 11/22/2022] Open
Abstract
Plant and insect trypanosomatids constitute the "lower trypanosomatids", which have been used routinely as laboratory models for biochemical and molecular studies because they are easily cultured under axenic conditions, and they contain homologues of virulence factors from the classic human trypanosomatid pathogens. Among the molecular factors that contribute to Leishmania spp. virulence and pathogenesis, the major surface protease, alternatively called MSP, PSP, leishmanolysin, EC 3.4.24.36 and gp63, is the most abundant surface protein of Leishmania promastigotes. A myriad of functions have been described for the gp63 from Leishmania spp. when the metacyclic promastigote is inside the mammalian host. However, less is known about the functions performed by this molecule in the invertebrate vector. Intriguingly, gp63 is predominantly expressed in the insect stage of Leishmania, and in all insect and plant trypanosomatids examined so far. The gp63 homologues found in lower trypanosomatids seem to play essential roles in the nutrition as well as in the interaction with the insect epithelial cells. Since excellent reviews were produced in the last decade regarding the roles played by proteases in the vertebrate hosts, we focused in the recent developments in our understanding of the biochemistry and cell biology of gp63-like proteins in lower trypanosomatids.
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Affiliation(s)
- André L S Santos
- Departamento de Microbiologia Geral, Instituto de Microbiologia Prof Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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36
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Ross AJ, Sizova OV, Nikolaev AV. Parasite glycoconjugates. Part 16: Synthesis of a disaccharide and phosphorylated di- and tri-saccharides from Leishmania lipophosphoglycan. Carbohydr Res 2006; 341:1954-64. [PMID: 16697981 DOI: 10.1016/j.carres.2006.03.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2005] [Revised: 03/05/2006] [Accepted: 03/21/2006] [Indexed: 11/24/2022]
Abstract
A neutral disaccharide beta-D-Galp-(1-->4)-alpha-D-Manp and phosphorylated di- and tri-saccharides beta-D-Galp-(1-->3)-[H(2)PO(3)-6]-beta-D-Galp-O[CH(2)](8)CHCH(2) and beta-D-Galp-(1-->3)-[H(2)PO(3)-6]-beta-D-Galp-(1-->4)-alpha-D-Manp, which are fragments of the phosphoglycan portion of the surface lipophosphoglycan from Leishmania donovani (the disaccharide) or Leishmania major (all three compounds), were prepared and used as TLC standards to help the identification and differentiation of the elongating and branching beta-D-galactosyl transferase activities in Leishmania. The phosphosaccharides were synthesised using the H-phosphonate method for phosphorylation.
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Affiliation(s)
- Andrew J Ross
- Faculty of Life Sciences, Division of Biological Chemistry and Molecular Microbiology, University of Dundee, UK
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37
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Caparrós E, Serrano D, Puig-Kröger A, Riol L, Lasala F, Martinez I, Vidal-Vanaclocha F, Delgado R, Rodríguez-Fernández JL, Rivas L, Corbí AL, Colmenares M. Role of the C-type lectins DC-SIGN and L-SIGN in Leishmania interaction with host phagocytes. Immunobiology 2005; 210:185-93. [PMID: 16164025 PMCID: PMC7114652 DOI: 10.1016/j.imbio.2005.05.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Leishmaniasis is a parasitic disease that courses with cutaneous or visceral clinical manifestations. The amastigote stage of the parasite infects phagocytes and modulates the effector function of the host cells. Our group has described that the interaction between Leishmania and immature monocyte-derived dendritic cells (DCs) takes place through dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN), a C-type lectin that specifically recognizes fungal, viral and bacterial pathogens. The DC-SIGN-mediated recognition of Leishmania amastigotes does not induce DC maturation, and the DC-SIGN ligand/s on Leishmania parasites is/are still unknown. We have also found that the DC-SIGN-related molecule L-SIGN, specifically expressed in lymph node and liver sinusoidal endothelial cells, acts as a receptor for L. infantum, the parasite responsible for visceral leishmaniasis, but does not recognize L. pifanoi, which causes the cutaneous form of the disease. Therefore, DC-SIGN and L-SIGN differ in their ability to interact with Leishmania species responsible for either visceral or cutaneous leishmaniasis. A deeper knowledge of the parasite-C-type lectin interaction may be helpful for the design of new DC-based therapeutic vaccines against Leishmania infections.
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Affiliation(s)
- Esther Caparrós
- Centro de Investigaciones Biológicas (CSIC), Calle Ramiro de Maeztu 9, 28040 Madrid, Spain
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Abstract
Various functions for glycosylphosphatidylinositol (GPI) protein anchors have been described in mammalian and protozoan systems. These data suggest that some functions are common to higher and lower eukaryotes, whereas others may represent adaptations that are specifically advantageous to either unicellular or metazoan organisms. In this article, Mike Ferguson discusses the current theories of GPI function that have relevance to protozoan parasites and their mammalian hosts.
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Affiliation(s)
- M A Ferguson
- Department of Biochemistry, University of Dundee, Dundee, UK DD1 4HN
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Higson AP, Ross AJ, Tsvetkov YE, Routier FH, Sizova OV, Ferguson MAJ, Nikolaev AV. Synthetic Fragments of Antigenic Lipophosphoglycans fromLeishmania major andLeishmania mexicana and Their Use for Characterisation of theLeishmania Elongating ?-D-Mannopyranosylphosphate Transferase. Chemistry 2005; 11:2019-30. [PMID: 15685582 DOI: 10.1002/chem.200400563] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The phosphorylated branched heptasaccharides 7 and 8, the octasaccharide 9 and the phosphorylated trisaccharides 5 and 6, which are fragments of the phosphoglycan portion of the surface lipophosphoglycans from Leishmania mexicana (5) or L. major (6-9), were synthesised by using the glycosyl hydrogenphosphonate method for the preparation of phosphodiester bridges. The compounds were tested as acceptor substrates/putative inhibitors for the Leishmania elongating alpha-D-mannosylphosphate transferase.
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Affiliation(s)
- Adrian P Higson
- Faculty of Life Sciences, Division of Biological Chemistry and Molecular Microbiology, University of Dundee (Carnelley Building), Dundee DD1 4HN, Scotland, UK
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Aebischer T, Bennett CL, Pelizzola M, Vizzardelli C, Pavelka N, Urbano M, Capozzoli M, Luchini A, Ilg T, Granucci F, Blackburn CC, Ricciardi-Castagnoli P. A critical role for lipophosphoglycan in proinflammatory responses of dendritic cells toLeishmania mexicana. Eur J Immunol 2005; 35:476-86. [PMID: 15657947 DOI: 10.1002/eji.200425674] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recognition of pathogen-associated molecular patterns (PAMP) influences the response of dendritic cells (DC) and therefore development of innate and adaptive immunity. Different forms of Leishmania mexicana have distinct effects on DC, with promastigotes and amastigotes being activating and apparently neutral, respectively. We investigated whether stage-specific differences in surface composition might account for these distinct effects. Amastigotes and promastigotes lacking the lpg1 gene needed for lipophosphoglycan (LPG) biosynthesis could not activate DC in vitro. Genome-wide transcriptional profiling of DC infected with wild-type or mutant promastigotes or wild-type amastigotes revealed that wild-type promastigotes induce an inflammatory signature that is lacking in DC exposed to the other parasite forms. The proinflammatory response pattern was partly recovered by reconstitution of lpg1 expression in lpg1-/- parasites, and exposure to purified LPG increased the expression of MHC class II and CD86 on DC. Infection with wild-type but not lpg1-/- promastigotes increased the number of activated DC in draining lymph nodes, and this was correlated with lower early parasite burdens in wild-type-infected animals. These in vivo and in vitro results suggest an LPG-dependent activation of DC that contributes to host defense and agree with the notion that the parasites evolved under immune pressure to down-regulate PAMP expression in mammalian hosts.
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Affiliation(s)
- Toni Aebischer
- Max-Planck-Institute for Infection Biology, Department of Molecular Biology, Berlin, Germany
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Verhamme IM, Bock PE, Jackson CM. The Preferred Pathway of Glycosaminoglycan-accelerated Inactivation of Thrombin by Heparin Cofactor II. J Biol Chem 2004; 279:9785-95. [PMID: 14701814 DOI: 10.1074/jbc.m313962200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thrombin (T) inactivation by the serpin, heparin cofactor II (HCII), is accelerated by the glycosaminoglycans (GAGs) dermatan sulfate (DS) and heparin (H). Equilibrium binding and thrombin inactivation kinetics at pH 7.8 and ionic strength (I) 0.125 m demonstrated that DS and heparin bound much tighter to thrombin (K(T(DS)) 1-5.8 microm; K(T(H)) 0.02-0.2 microm) than to HCII (K(HCII(DS)) 236-291 microm; K(HCII(H)) 25-35 microm), favoring formation of T.GAG over HCII.GAG complexes as intermediates for T.GAG.HCII complex assembly. At [GAG] << K(HCII(GAG)) the GAG and HCII concentration dependences of the first-order inactivation rate constants (k(app)) were hyperbolic, reflecting saturation of T.GAG complex and formation of the T.GAG.HCII complex from T.GAG and free HCII, respectively. At [GAG] >> K(HCII(GAG)), HCII.GAG complex formation caused a decrease in k(app). The bell-shaped logarithmic GAG dependences fit an obligatory template mechanism in which free HCII binds GAG in the T.GAG complex. DS and heparin bound fluorescently labeled meizothrombin(des-fragment 1) (MzT(-F1)) with K(MzT(-F1)(GAG)) 10 and 20 microm, respectively, demonstrating a binding site outside of exosite II. Exosite II ligands did not attenuate the DS-accelerated thrombin inactivation markedly, but DS displaced thrombin from heparin-Sepharose, suggesting that DS and heparin share a restricted binding site in or nearby exosite II, in addition to binding outside exosite II. Both T.DS and MzT(-F1).DS interactions were saturable at DS concentrations substantially below K(HCII(DS)), consistent with DS bridging T.DS and free HCII. The results suggest that GAG template action facilitates ternary complex formation and accommodates HCII binding to GAG and thrombin exosite I in the ternary complex.
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Affiliation(s)
- Ingrid M Verhamme
- Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2561, USA.
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Yao C, Donelson JE, Wilson ME. The major surface protease (MSP or GP63) of Leishmania sp. Biosynthesis, regulation of expression, and function. Mol Biochem Parasitol 2004; 132:1-16. [PMID: 14563532 DOI: 10.1016/s0166-6851(03)00211-1] [Citation(s) in RCA: 217] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Leishmania sp. are digenetic protozoa that cause an estimated 1.5-2 million new cases of leishmaniasis per year worldwide. Among the molecular factors that contribute to Leishmania sp. virulence and pathogenesis is the major surface protease, alternately called MSP, GP63, leishmanolysin, EC3.4.24.36, and PSP, which is the most abundant surface protein of leishmania promastigotes. Recent studies using gene knockout, antisense RNA and overexpression mutants have demonstrated a role for MSP in resistance of promastigotes to complement-mediated lysis and either a direct or indirect role in receptor-mediated uptake of leishmania. The MSP gene clusters in different Leishmania sp. include multiple distinct MSPs that tend to fall into three classes, which can be distinguished by their sequences and by their differential expression in parasite life stages. Regulated expression of MSP class gene products during the parasite life cycle occurs at several levels involving both mRNA and protein metabolism. In this review we summarize advances in MSP research over the past decade, including organization of the gene families, crystal structure of the protein, regulation of mRNA and protein expression, biosynthesis and possible functions. The MSPs exquisitely demonstrate the multiple levels of post-transcriptional gene regulation that occur in Leishmania sp. and other trypanosomatid protozoa.
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Affiliation(s)
- Chaoqun Yao
- VA Medical Center, University of Iowa, Iowa City, IA 52242, USA.
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Colmenares M, Corbí AL, Turco SJ, Rivas L. The Dendritic Cell Receptor DC-SIGN Discriminates among Species and Life Cycle Forms ofLeishmania. THE JOURNAL OF IMMUNOLOGY 2004; 172:1186-90. [PMID: 14707095 DOI: 10.4049/jimmunol.172.2.1186] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Infection of dendritic cells by the human protozoal parasite Leishmania is part of its survival strategy. The dendritic cell receptors for Leishmania have not been established and might differ in their interactions among Leishmania species and infective stages. We present evidence that the surface C-type lectin DC-SIGN (CD 209) is a receptor for promastigote and amastigote infective stages from both visceral (Leishmania infantum) and New World cutaneous (Leishmania pifanoi) Leishmania species, but not for Leishmania major metacyclic promastigotes, an Old World species causing cutaneous leishmaniasis. Leishmania binding to DC-SIGN was found to be independent of lipophosphoglycan, the major glycoconjugate of the promastigote plasma membrane. Our findings emphasize the relevance of DC-SIGN in Leishmania-dendritic cell interactions, an essential link between innate and Leishmania-specific adaptive immune responses, and suggest that DC-SIGN might be a therapeutic target for both visceral and cutaneous leishmaniasis
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Affiliation(s)
- María Colmenares
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Cientificas, Ramiro de Maeztu 9, 28040 Madrid, Spain
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Abstract
Proteases from a variety of protozoan parasites have been characterized at the molecular and cellular levels, and the many roles that proteases play in these organisms are coming into focus. Central roles have been proposed for proteases in diverse processes such as host cell invasion and egress, encystation, excystation, catabolism of host proteins, differentiation, cell cycle progression, cytoadherence, and both stimulation and evasion of host immune responses. Detailed structural and functional characterization of parasite proteases has led to novel insights into the workings of these fascinating catalytic machines. The possibility of developing selective inhibitors of key proteases of pathogenic parasites into novel chemotherapeutic strategies is being vigorously explored.
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Affiliation(s)
- Michael Klemba
- Departments of Medicine and Molecular Microbiology, Howard Hughes Medical Institute, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, Missouri 63110, USA.
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45
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Courret N, Fréhel C, Gouhier N, Pouchelet M, Prina E, Roux P, Antoine JC. Biogenesis ofLeishmania-harbouring parasitophorous vacuoles following phagocytosis of the metacyclic promastigote or amastigote stages of the parasites. J Cell Sci 2002; 115:2303-16. [PMID: 12006615 DOI: 10.1242/jcs.115.11.2303] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Protozoan parasites Leishmania alternate between a flagellated promastigote form and an amastigote form. In their mammalian hosts, Leishmania survive and multiply in macrophages. Both forms can be internalized by these host cells at different stages of the infectious process and eventually establish themselves within parasitophorous vacuoles exhibiting phagolysosomal properties. To determine whether the biogenesis of these organelles differs according to the parasitic stage used to initiate infection, we compared their formation kinetics after phagocytosis of either metacyclic promastigotes or amastigotes of L. amazonensis or of L. major by mouse bone-marrow-derived macrophages pre-exposed or not to IFN-γ. After 10 minutes of contact, an accumulation of F-actin was observed around the promastigotes and amatigotes undergoing phagocytosis or those that had already been internalized. This accumulation was transient and rapidly disappeared at later times. At 30 minutes, most of the promastigotes were located in long, narrow organelles that were exactly the same shape as the parasites. The latter were elongated with their cell bodies near to the macrophage nucleus and their flagella towards the periphery. This suggests that promastigote phagocytosis mainly occurs in a polarized manner, with the cell body entering the macrophages first. Most, if not all, of the phagocytosed promastigotes were located in organelles that rapidly acquired phagolysosomal properties. At 30 minutes, lamp-1, macrosialin, cathepsins B and D were detected in 70-98% of these compartments and about 70% of them were surrounded by rab7p. These late endosome/lysosome `markers' were recruited through fusion with late endocytic compartments. Indeed, when late endosomes/lysosomes were loaded with fluorescein dextran, 81-98% of the promastigote-harbouring compartments contained the endocytic tracer 30 minutes after infection. Electron microscopy of infected macrophages previously loaded with peroxidase confirmed that the phagosomes rapidly fused with late endocytic compartments. When the amastigote stage of L. amazonensiswas used to initiate infection, the kinetics of acquisition of the different late endosome/lysosome `markers' by the phagosomes were similar to those measured after infection with metacyclics. However, more rab7p+-phagosomes were observed at early time points (e.g. 90% were rab7p+ at 30 minutes). The early endosome `markers', EEA1 and the transferrin receptor, were hardly detected in parasite-containing compartments regardless of the parasitic stage used to infect macrophages and the time after infection. In conclusion, both metacyclic- and amastigote-containing phagosomes fuse with late endosomes/lysosomes within 30 minutes. However, with L. amazonensis, the time required for the formation of the huge parasitophorous vacuoles, which are characteristic of this species, was much shorter after infection with amastigotes than after infection with metacyclic promastigotes. This indicates that the initial fusions with late endosomes/lysosomes are followed by a stage-specific sequence of events.
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Affiliation(s)
- Nathalie Courret
- Unité d'Immunophysiologie et Parasitisme Intracellulaire, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
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46
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Montgomery J, Curtis J, Handman E. Genetic and structural heterogeneity of proteophosphoglycans in Leishmania. Mol Biochem Parasitol 2002; 121:75-85. [PMID: 11985864 DOI: 10.1016/s0166-6851(02)00024-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Proteophosphoglycans (PPG) are a large family of extensively glycosylated proteins with some unusual and unique features. The ppg gene family is conserved in at least three Leishmania species and localises to chromosome 35. Previous studies using standard discontinuous SDS-PAGE have been incapable of resolving PPG heterogeneity with most material failing to enter the resolving gel. We have exploited a continuous electrophoretic system, which allows for the first time the separation and characterisation of a low molecular weight population of PPG polypeptides. We provide evidence of surface expressed and developmentally regulated forms. Among those, we identify for the first time the previously described membrane-bound PPG and a form of filamentous fPPG, which is altered, or absent in two of the three L. major isolates examined.
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Affiliation(s)
- Jacqui Montgomery
- The Walter and Eliza Hall Institute of Medical Research, Post Office, Royal Melbourne Hospital, Vic., Australia
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47
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Abstract
Leishmania are a resilient group of intracellular parasites that infect macrophages. The resultant complex of diseases, or leishmaniases, caused by the parasites affect over twelve million people worldwide. Leishmania have developed unique adaptive mechanisms to ensure their survival in the harsh environments faced throughout their life cycle. These parasites must not only contend with the hostile digestive conditions found within the sand fly vector, but they must also avoid destruction by the host immune system while in the bloodstream, before entering the macrophage. To do so, Leishmania express unique lipophosphoglycan (LPG) molecules and the metalloprotease gp63, among other proteins, on their cell surface. To enter the macrophage, Leishmania utilizes a variety of cellular receptors to mediate endocytosis. Once inside the macrophage, Leishmania is protected from phagolysosome degradation by a variety of adaptations to inhibit cellular defense mechanisms. These include the inhibition of phagosome-endosome fusion, hydrolytic enzymes, cell signaling pathways, nitric oxide production, and cytokine production. While other parasites can also infect macrophages, Leishmania is distinctive in that it not only relies on its own defenses to survive and reproduce within the macrophage phagolysosome, but Leishmania also manipulates the host immune response in order to protect itself and to gain entry into the cell. These unique adaptive mechanisms help promote Leishmania survival.
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Affiliation(s)
- Anna C Cunningham
- Department of Pathology, The University of Tennessee, Memphis, Tennessee 38163, USA
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48
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McConville MJ, Mullin KA, Ilgoutz SC, Teasdale RD. Secretory pathway of trypanosomatid parasites. Microbiol Mol Biol Rev 2002; 66:122-54; table of contents. [PMID: 11875130 PMCID: PMC120783 DOI: 10.1128/mmbr.66.1.122-154.2002] [Citation(s) in RCA: 175] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The Trypanosomatidae comprise a large group of parasitic protozoa, some of which cause important diseases in humans. These include Trypanosoma brucei (the causative agent of African sleeping sickness and nagana in cattle), Trypanosoma cruzi (the causative agent of Chagas' disease in Central and South America), and Leishmania spp. (the causative agent of visceral and [muco]cutaneous leishmaniasis throughout the tropics and subtropics). The cell surfaces of these parasites are covered in complex protein- or carbohydrate-rich coats that are required for parasite survival and infectivity in their respective insect vectors and mammalian hosts. These molecules are assembled in the secretory pathway. Recent advances in the genetic manipulation of these parasites as well as progress with the parasite genome projects has greatly advanced our understanding of processes that underlie secretory transport in trypanosomatids. This article provides an overview of the organization of the trypanosomatid secretory pathway and connections that exist with endocytic organelles and multiple lytic and storage vacuoles. A number of the molecular components that are required for vesicular transport have been identified, as have some of the sorting signals that direct proteins to the cell surface or organelles in the endosome-vacuole system. Finally, the subcellular organization of the major glycosylation pathways in these parasites is reviewed. Studies on these highly divergent eukaryotes provide important insights into the molecular processes underlying secretory transport that arose very early in eukaryotic evolution. They also reveal unusual or novel aspects of secretory transport and protein glycosylation that may be exploited in developing new antiparasite drugs.
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Affiliation(s)
- Malcolm J McConville
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia.
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49
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Colmenares M, Tiemeyer M, Kima P, McMahon-Pratt D. Biochemical and biological characterization of the protective Leishmania pifanoi amastigote antigen P-8. Infect Immun 2001; 69:6776-84. [PMID: 11598050 PMCID: PMC100055 DOI: 10.1128/iai.69.11.6776-6784.2001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Leishmania pifanoi amastigote antigen P-8 has been previously shown to induce protective immunity in a murine model of cutaneous leishmaniasis (L. Soong, S. M. Duboise, P. Kima, and D. McMahon-Pratt, Infect. Immun. 63:3559-3566, 1995). As this antigen is of interest for further vaccine studies, the biochemical characterization of P-8 was undertaken. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western-blot analysis, and gel filtration chromatography revealed that P-8 antigen consisted of two proteoglycolipid complexes. The P-8 epitope is associated with the L. pifanoi amastigote-specific glycolipid components found in the two complexes. The P-8 complex 1 (P-8c1) consists of a 56-kDa serine metalloproteinase, apolipoprotein E (derived from fetal bovine serum), and amastigote-specific glycolipids. The P-8 complex 2 (P-8c2) consists of a 31-kDa cysteine proteinase associated with amastigote glycolipids. Biochemical analyses suggest that the P-8 antigenic glycolipids may be distinct from previously described Leishmania glycolipids (glycosylinositol-phospholipids and sphingoglycolipids). Protective immunity studies revealed that P-8c1 (serine metalloproteinase-glycolipid complex) confers comparable protection against infection as immunopurified P-8. The isolated P-8c2 (cysteine proteinase-glycolipid complex) does not provide significant protection, nor does stimulation with P-8c2 result in significant T-cell activation in P-8- or P-8c2-vaccinated mice. Consequently, the P-8c1 complex appears to be the immunodominant component of P-8.
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Affiliation(s)
- M Colmenares
- Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut, USA
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50
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McKean PG, Denny PW, Knuepfer E, Keen JK, Smith DF. Phenotypic changes associated with deletion and overexpression of a stage-regulated gene family in Leishmania. Cell Microbiol 2001; 3:511-23. [PMID: 11488813 DOI: 10.1046/j.1462-5822.2001.00135.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The LmcDNA16 locus of Leishmania major contains three highly related genes HASPA1, HASPA2 and HASPB, encoding hydrophilic, acylated surface proteins and a tandem pair of unrelated sequences, SHERP1 and SHERP2, coding for a small, hydrophilic protein that localizes to the endoplasmic reticulum and outer mitochondrial membrane. Differential regulation of these genes results in expression of a subset of the HASP proteins and SHERP only in infective stage parasites. To assess the contribution of these molecules to parasite virulence, the diploid LmcDNA16 gene locus has been removed by targeted gene deletion. Homozygous null mutants have precise deletions of both alleles and exhibit no HASP or SHERP expression. They are at least as virulent as wild-type parasites in macrophage invasion and intracellular survival assays, both in vitro and in vivo. Conversely, null mutants engineered to overexpress the entire LmcDNA16 gene locus are unable to survive within the intramacrophage environment despite their differentiation into infective metacyclic parasites. Both null and overexpressing null parasites show increased sensitivity to complement-mediated lysis, suggesting perturbation of their surface architecture. Avirulence in overexpressing parasites correlates with selective depletion of a specific lipid species, decreased expression of the major surface glycoprotein GP63, but no significant downregulation of the glycoconjugate lipophosphoglycan.
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Affiliation(s)
- P G McKean
- Wellcome Trust Laboratories for Molecular Parasitology, Department of Biochemistry, Imperial College of Science, Technology and Medicine, South Kensington, London SW7 2AY, UK
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