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Marshall S, Kelly PH, Singh BK, Pope RM, Kim P, Zhanbolat B, Wilson ME, Yao C. Extracellular release of virulence factor major surface protease via exosomes in Leishmania infantum promastigotes. Parasit Vectors 2018; 11:355. [PMID: 29921321 PMCID: PMC6006689 DOI: 10.1186/s13071-018-2937-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 06/06/2018] [Indexed: 11/17/2022] Open
Abstract
Background The Leishmania spp. protozoa are introduced into humans through a sand fly blood meal, depositing the infectious metacyclic promastigote form of the parasite into human skin. Parasites enter a variety of host cells, although a majority are found in macrophages where they replicate intracellularly during chronic leishmaniasis. Symptomatic leishmaniasis causes considerable human morbidity in endemic regions. The Leishmania spp. evade host microbicidal mechanisms partially through virulence-associated proteins such as the major surface protease (MSP or GP63), to inactivate immune factors in the host environment. MSP is a metalloprotease encoded by a tandem array of genes belonging to three msp gene classes, whose mRNAs are differentially expressed in different life stages of the parasite. Like other cells, Leishmania spp. release small membrane-bound vesicles called exosomes into their environment. The purpose of this study was to detect MSP proteins in exosomal vesicles of Leishmania spp. protozoa. Methods Using mass spectrometry data we determined the profile of MSP class proteins released in L. infantum exosomes derived from promastigotes in their avirulent procyclic (logarithmic) stage and virulent stationary and metacyclic stages. MSP protein isoforms belonging to each of the three msp gene classes could be identified by unique peptides. Results Metacyclic promastigote exosomes contained the highest, and logarithmic exosomes had the lowest abundance of total MSP. Among the MSP classes, MSPC class had the greatest variety of isoforms, but was least abundant in all exosomes. Nonetheless, all MSP classes were present at higher levels in exosomes released from stationary or metacyclic promastigotes than logarithmic promastigotes. Conclusions The data suggest the efficiency of exosome release may be more important than the identity of MSP isoform in determining the MSP content of Leishmania spp. exosomes. Electronic supplementary material The online version of this article (10.1186/s13071-018-2937-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Skye Marshall
- Department of Biomedical Sciences and One Health Center for Zoonoses and Tropical Veterinary Medicine, Ross University School of Veterinary Medicine, St. Kitts & Nevis, West Indies, USA
| | - Patrick H Kelly
- Department of Microbiology, University of Iowa, Iowa City, IA, USA
| | - Brajesh K Singh
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA.,Present address: Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - R Marshall Pope
- The Proteomics Facility, University of Iowa, Iowa City, IA, USA
| | - Peter Kim
- Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Bayan Zhanbolat
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | - Mary E Wilson
- Department of Microbiology, University of Iowa, Iowa City, IA, USA.,Department of Internal Medicine, University of Iowa, Iowa City, IA, USA.,Department of Epidemiology, University of Iowa, Iowa City, IA, USA.,Iowa City VA Medical Center, Iowa City, IA, USA
| | - Chaoqun Yao
- Department of Biomedical Sciences and One Health Center for Zoonoses and Tropical Veterinary Medicine, Ross University School of Veterinary Medicine, St. Kitts & Nevis, West Indies, USA.
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Rhaiem RB, Houimel M. Targeting Leishmania major parasite with peptides derived from a combinatorial phage display library. Acta Trop 2016; 159:11-9. [PMID: 26995695 DOI: 10.1016/j.actatropica.2016.03.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/09/2016] [Accepted: 03/14/2016] [Indexed: 10/27/2022]
Abstract
Cutaneous leishmaniasis (CL) is a global problem caused by intracellular protozoan pathogens of the genus Leishmania for which there are no suitable vaccine or chemotherapy options. Thus, de novo identification of small molecules binding to the Leishmania parasites by direct screening is a promising and appropriate alternative strategy for the development of new drugs. In this study, we used a random linear hexapeptide library fused to the gene III protein of M13 filamentous bacteriophage to select binding peptides to metacyclic promastigotes from a highly virulent strain of Leishmania major (Zymodeme MON-25; MHOM/TN/94/GLC94). After four rounds of stringent selection and amplification, polyclonal and monoclonal phage-peptides directed against L. major metacyclic promastigotes were assessed by ELISA, and the optimal phage-peptides were grown individually and characterized for binding to L. major by monoclonal phage ELISA. The DNA of 42 phage-peptides clones was amplified by PCR, sequenced, and their amino acid sequences deduced. Six different peptide sequences were obtained with frequencies of occurrence ranging from 2.3% to 85.7%. The biological effect of the peptides was assessed in vitro on human monocytes infected with L. major metacyclic promastigotes, and in vivo on susceptible parasite-infected BALB/c mice. The development of cutaneous lesions in the right hind footpads of infected mice after 13 weeks post-infection showed a protection rate of 81.94% with the injected peptide P2. Moreover, Western blots revealed that the P2 peptide interacted with the major surface protease gp63, a protein of 63kDa molecular weight. Moreover, bioinformatics were used to predict the interaction between peptides and the major surface molecule of the L. major. The molecular docking showed that the P2 peptide has the minimum interaction energy and maximum shape complimentarity with the L. major gp63 active site. Our study demonstrated that the P2 peptide occurs at high frequency during the screening procedure, best inhibits L. major growth kinetics in vitro, and reduces cutaneous lesions in BALB/c mice, thus showing great promise in the development of new therapeutic molecules.
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Abstract
Leishmania is an infectious protozoan parasite related to African and American trypanosomes. All Leishmania species that are pathogenic to humans can cause dermal disease. When one is confronted with cutaneous leishmaniasis, identification of the causative species is relevant in both clinical and epidemiological studies, case management, and control. This review gives an overview of the currently existing and most used assays for species discrimination, with a critical appraisal of the limitations of each technique. The consensus taxonomy for the genus is outlined, including debatable species designations. Finally, a numerical literature analysis is presented that describes which methods are most used in various countries and regions in the world, and for which purposes.
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Affiliation(s)
- Gert Van der Auwera
- Institute of Tropical Medicine, Department of Biomedical Sciences, Antwerp, Belgium
| | - Jean-Claude Dujardin
- Institute of Tropical Medicine, Department of Biomedical Sciences, Antwerp, Belgium Antwerp University, Department of Biomedical Sciences, Antwerp, Belgium
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Attenuation of Leishmania infantum chagasi metacyclic promastigotes by sterol depletion. Infect Immun 2013; 81:2507-17. [PMID: 23630964 DOI: 10.1128/iai.00214-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The infectious metacyclic promastigotes of Leishmania protozoa establish infection in a mammalian host after they are deposited into the dermis by a sand fly vector. Several Leishmania virulence factors promote infection, including the glycosylphosphatidylinositol membrane-anchored major surface protease (MSP). Metacyclic Leishmania infantum chagasi promastigotes were treated with methyl-beta-cyclodextrin (MβCD), a sterol-chelating reagent, causing a 3-fold reduction in total cellular sterols as well as enhancing MSP release without affecting parasite viability in vitro. MβCD-treated promastigotes were more susceptible to complement-mediated lysis than untreated controls and reduced the parasite load 3-fold when inoculated into BALB/c mice. Paradoxically, MβCD-treated promastigotes caused a higher initial in vitro infection rate in human or murine macrophages than untreated controls, although their intracellular multiplication was hindered upon infection establishment. There was a corresponding larger amount of covalently bound C3b than iC3b on the parasite surfaces of MβCD-treated promastigotes exposed to healthy human serum in vitro, as well as loss of MSP, a protease that enhances C3b cleavage to iC3b. Mass spectrometry showed that MβCD promotes the release of proteins into the extracellular medium, including both MSP and MSP-like protein (MLP), from virulent metacyclic promastigotes. These data support the hypothesis that plasma membrane sterols are important for the virulence of Leishmania protozoa at least in part through retention of membrane virulence proteins.
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Abstract
Membrane vesicles secreted by Leishmania mexicana were collected and analyzed. These vesicles can bind plasminogen and were shown to contain enolase, previously identified as a plasminogen-binding protein. In addition, another plasminogen-binding protein was identified, the small myristoylated protein, SMP-1. Recombinant SMP-1 was able to bind plasminogen in a lysine-dependent manner with a K(d) value of 0.24 μM. The C-terminal lysine seems to be responsible for this binding, since this recognition decreases upon carboxypeptidase B treatment. This protein was present within the secreted membrane vesicles as demonstrated by its protection from trypsin digestion in the absence of Triton X-100. Plasminogen-binding proteins in the secreted vesicles may be involved in parasite invasion in the mammalian host.
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Efficacy of synthetic peptides RP-1 and AA-RP-1 against Leishmania species in vitro and in vivo. Antimicrob Agents Chemother 2011; 56:658-65. [PMID: 22123683 DOI: 10.1128/aac.05349-11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Host defense peptides are naturally occurring molecules that play essential roles in innate immunity to infection. Based on prior structure-function knowledge, we tested two synthetic peptides (RP-1 and AA-RP-1) modeled on the conserved, microbicidal α-helical domain of mammalian CXCL4 platelet kinocidins. These peptides were evaluated for efficacy against Leishmania species, the causative agents of the group of diseases known as leishmaniasis. In vitro antileishmanial activity was assessed against three distinct Leishmania strains by measuring proliferation, metabolic activity and parasite viability after exposure to various concentrations of peptides. We demonstrate that micromolar concentrations of RP-1 and AA-RP-1 caused dose-dependent growth inhibition of Leishmania promastigotes. This antileishmanial activity correlated with rapid membrane disruption, as well as with a loss of mitochondrial transmembrane potential. In addition, RP-1 and AA-RP-1 demonstrated distinct and significant in vivo antileishmanial activities in a mouse model of experimental visceral leishmaniasis after intravenous administration. These results establish efficacy of RP-1 lineage synthetic peptides against Leishmania species in vitro and after intravenous administration in vivo and provide further validation of proof of concept for the development of these and related systemic anti-infective peptides targeting pathogens that are resistant to conventional antibiotics.
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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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Rebello KM, Britto C, Pereira BAS, Pita-Pereira DD, Moraes MO, Ferreira ABR, Cysne-Finkelstein L, Otto TD, Côrtes LMDC, da-Silva GG, Alves CR. Leishmania (Viannia) braziliensis: influence of successive in vitro cultivation on the expression of promastigote proteinases. Exp Parasitol 2010; 126:570-6. [PMID: 20553928 DOI: 10.1016/j.exppara.2010.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 06/01/2010] [Accepted: 06/02/2010] [Indexed: 11/24/2022]
Abstract
Cysteine proteinases are an important virulence factor in Leishmania parasites. In this study we analyzed the cysteine proteinase expression of infective Leishmania (Viannia) braziliensis promastigotes, examining the expression induced by successive in vitro passages in culture. We observed that this parasite presents a decrease in its virulence over BALB/c macrophages, after successive passages in culture, but still they present proteinase activity, being capable of hydrolyzing the substrate pGlu-Phe-Leu-p Nitroanilide at pH 7.0. This proteinase activity also decreases in the course of the successive passages. Additionally, the decrease in the amount of CPB proteins following successive passages of promastigotes was verified by immunoblotting assays, using an anti-CPB antiserum. Real-time PCR assays were performed to assess the relative cpb expression when compared to a housekeeping gene in promastigote cDNA preparations from the first, fourth and seventh passages. Interestingly, the data indicate a relative increase in cpb gene transcripts as the promastigotes were maintained under in vitro culture: 2.2 times higher for fourth and 2.7 times higher for seventh passages when compared to the first passage. Thus, the information gathered here shows that the expression of cysteine proteinases is modified during in vitro cultivation of L. (V.) braziliensis promastigotes.
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Affiliation(s)
- Karina Mastropasqua Rebello
- Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, RJ, Brazil
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Yao C, Li Y, Donelson JE, Wilson ME. Proteomic examination of Leishmania chagasi plasma membrane proteins: Contrast between avirulent and virulent (metacyclic) parasite forms. Proteomics Clin Appl 2009; 4:4-16. [PMID: 21137013 DOI: 10.1002/prca.200900050] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 07/31/2009] [Accepted: 09/09/2009] [Indexed: 12/29/2022]
Abstract
PURPOSE About two million new cases of leishmaniasis with 50 000 associated deaths occur worldwide each year. Promastigotes of the causative Leishmania spp. develop from the procyclic stage to the highly virulent metacyclic stage within the sand fly vector. We hypothesized that proteins important for promastigote virulence might be uniquely represented in the plasma membrane of metacyclic, but not procyclic, promastigotes. EXPERIMENTAL DESIGN Procyclic (logarithmic) promastigotes and purified metacyclic promastigotes from stationary phase cultures of Leishmania chagasi were used to prepare membrane preparations either by surface biotinylation-streptavidin affinity separation or by octyl glucoside detergent extraction. RESULTS These membrane fractions were enriched over 130- and 250-fold, respectively, as estimated by Western blotting for the plasma membrane's major surface protease. Hundreds or dozens of proteins were identified by LC-MS/MS in the surface biotinylation or detergent extraction, respectively. Confocal microscopy suggested the difference between the lists was due to the fact that proteins localized both on the surface membrane and within the flagellar pocket were accessible to surface biotinylation, whereas only proteins on the membrane were obtained by detergent extraction. Using detergent extraction, we found different proteins were present in membranes of the procyclic stage compared to metacyclic stage promastigotes. Several dozen were stage specific. CONCLUSIONS AND CLINICAL RELEVANCE These data provide a foundation for identifying virulence factors in the plasma membranes of Leishmania spp. promastigotes during metacyclogenesis.
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Affiliation(s)
- Chaoqun Yao
- Department of Internal Medicine, University of Iowa, Iowa City, USA.
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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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Hallé M, Gomez MA, Stuible M, Shimizu H, McMaster WR, Olivier M, Tremblay ML. The Leishmania surface protease GP63 cleaves multiple intracellular proteins and actively participates in p38 mitogen-activated protein kinase inactivation. J Biol Chem 2008; 284:6893-908. [PMID: 19064994 DOI: 10.1074/jbc.m805861200] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The Leishmania parasite is a widespread disease threat in tropical areas, causing symptoms ranging from skin lesions to death. Leishmania parasites typically invade macrophages but are also capable of infecting fibroblasts, which may serve as a reservoir for recurrent infection. Invasion by intracellular pathogens often involves exploitation of the host cell cytoskeletal and signaling machinery. Here we have observed a dramatic rearrangement of the actin cytoskeleton and marked modifications in the profile of protein tyrosine phosphorylation in fibroblasts infected with Leishmania major. Correspondingly, exposure to L. major resulted in degradation of the phosphorylated adaptor protein p130Cas and the protein-tyrosine phosphatase-PEST. Cellular and in vitro assays using pharmacological protease inhibitors, recombinant enzyme, and genetically modified strains of L. major identified the parasite protease GP63 as the principal catalyst of proteolysis during infection. A number of additional signaling proteins were screened for degradation during L. major infection as follows: a small subset was cleaved, including cortactin, T-cell protein-tyrosine phosphatase, and caspase-3, but the majority remained unaffected. Protein degradation occurred in cells incubated with Leishmania extracts in the absence of intact parasites, suggesting a mechanism permitting transfer of functional GP63 into the intracellular space. Finally, we evaluated the impact of Leishmania on MAPK signaling; unlike p44/42 and JNK, p38 was inactivated upon infection in a GP63- and protein degradation-dependent manner, which likely involves cleavage of the upstream adaptor TAB1. Our results establish that GP63 plays a central role in a number of hostcell molecular events that likely contribute to the infectivity of Leishmania.
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Affiliation(s)
- Maxime Hallé
- Rosalind and Morris Goodman Cancer Centre, Department of Biochemistry, McGill University, Montréal, Québec H3A 1A3, Canada
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Cuervo P, Santos ALS, Alves CR, Menezes GC, Silva BA, Britto C, Fernandes O, Cupolillo E, Batista De Jesus J. Cellular localization and expression of gp63 homologous metalloproteases in Leishmania (Viannia) braziliensis strains. Acta Trop 2008; 106:143-8. [PMID: 18423419 DOI: 10.1016/j.actatropica.2008.03.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 02/12/2008] [Accepted: 03/03/2008] [Indexed: 11/19/2022]
Abstract
Leishmania (Viannia) braziliensis is the major causative agent of American tegumentary leishmaniasis, a disease that encompasses a broad spectrum of clinical manifestations. In a previous study, we showed that Brazilian and Colombian L. braziliensis strains, isolated from patients with distinct clinical manifestations, display different pattern of metalloprotease activities. Following these results, we investigated the cellular localization of these molecules and their relation to the major surface protease (gp63) of Leishmania. Comparative analyses of metalloprotease expression among different clinical isolates as well as an evaluation of the effect of long-term in vitro passage on the expression pattern of these metalloproteases were also performed. Western blot analysis, using an anti-gp63 antibody, revealed polypeptide patterns with a similar profile to that observed in zymographic analysis. Flow cytometry and fluorescence microscopy analyses corroborated the presence of metalloproteases with homologous domains to gp63 in the parasites and revealed differences in the expression level of such molecules among the isolates. The cellular distribution of metalloproteases, assessed by confocal analysis, showed the existence of intracellular metalloproteases with homologous domains to gp63, predominantly located near the flagellar pocket. Finally, it was observed that differential zymographic profiles of metalloproteases exhibited by L. (V.) braziliensis isolates remain unaltered during prolonged in vitro culture, suggesting that the proteolytic activity pattern is a stable phenotypic characteristic of these parasites.
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Affiliation(s)
- Patricia Cuervo
- Laboratório de Pesquisa em Leishmanioses, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
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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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Yao C, Chen Y, Sudan B, Donelson JE, Wilson ME. Leishmania chagasi: homogenous metacyclic promastigotes isolated by buoyant density are highly virulent in a mouse model. Exp Parasitol 2007; 118:129-33. [PMID: 17706646 PMCID: PMC2274777 DOI: 10.1016/j.exppara.2007.06.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Revised: 05/08/2007] [Accepted: 06/26/2007] [Indexed: 10/23/2022]
Abstract
Homogenous metacyclic promastigotes of Leishmania chagasi were isolated by buoyant density from in vitro heterogeneous cultures and used for biochemical characterization of isoforms of the major surface protease (MSP). Compared to stationary phase promastigotes, metacyclic cells had three times more MSP, produced 3-fold higher parasite loads in a mouse model in vivo, and were more resistant to complement-mediated lysis in vitro. These metacyclic L. chagasi expressed both the virulence-associated 59-kDa, and the constitutively expressed 63-kDa, isoforms of MSP.
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Affiliation(s)
- Chaoqun Yao
- Department of Internal Medicine, University of Iowa, IA 52242, USA.
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Yao C, Luo J, Hsiao CHC, Donelson JE, Wilson ME. Leishmania chagasi: a tetracycline-inducible cell line driven by T7 RNA polymerase. Exp Parasitol 2007; 116:205-13. [PMID: 17320870 PMCID: PMC2231517 DOI: 10.1016/j.exppara.2007.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 12/22/2006] [Accepted: 01/02/2007] [Indexed: 11/24/2022]
Abstract
Trypanosomatid protozoa lack consensus promoters for RNA polymerase (RNAP) II. However, the artificial insertion of the T7 promoter (P(T7)) and the tetracycline repressor into Trypanosoma brucei cell lines expressing T7RNAP allows P(T7)-driven gene expression to be tetracycline-inducible. These cell lines provide a molecular tool to address protein function by several recombinant approaches. We describe here the development of an analogous Leishmania chagasi cell line bearing the genes for exogenous T7RNAP and the tetracycline repressor inserted in the multi-gene alpha-tubulin locus. A plasmid construct with P(T7) and the tetracycline operator upstream of a reporter gene, when introduced into this cell line as episomal plasmids or chromosomal insertion into the non-coding strand of an 18SrRNA gene, resulted in tetracycline-inducible expression of the reporter as much as 16- and 150-fold, respectively. The reporter was under a much tighter control when chromosomally inserted than extra-chromosomally born. Furthermore, P(T7) augmented the reporter's expression 2-fold more in comparison to P(T7)-less constructs. This cell line is the first Leishmania spp. that allows the exogenous T7RNAP-driven gene expression to be tetracycline-inducible; and may provide a useful tool for addressing protein function by manipulating expression levels of Leishmania endogenous genes.
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Affiliation(s)
- Chaoqun Yao
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA.
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17
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Salotra P, Duncan RC, Singh R, Subba Raju BV, Sreenivas G, Nakhasi HL. Upregulation of surface proteins in Leishmania donovani isolated from patients of post kala-azar dermal leishmaniasis. Microbes Infect 2006; 8:637-44. [PMID: 16469521 DOI: 10.1016/j.micinf.2005.08.018] [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: 04/08/2005] [Revised: 08/11/2005] [Accepted: 08/30/2005] [Indexed: 11/19/2022]
Abstract
Five to fifteen percent of visceral leishmaniasis (VL) patients in India develop post kala-azar dermal leishmaniasis (PKDL), usually 1-2 years after apparent clinical cure. There is evidence pointing to a role played by the host immune responses in the disease pathogenesis, however, the contribution of changes in parasite gene expression has not been explored. Highly sensitive gene expression microarray technology was employed to identify genes that are differentially expressed in Leishmania parasites isolated from PKDL patients in comparison with those from VL. Hybridization on Leishmania donovani genomic microarray comprised of unique clones allowed us to identify 46/2268 (2%) clones that showed statistically significant (P<0.05) changes in expression (1.5-3.5-fold) in parasites of PKDL origin compared to those of VL origin. Sequence analysis of six genomic clones, consistently showing approximately 2-fold higher expression in PKDL parasites, revealed significant homology with gp63, gp46, putative amastin, a putative reductase and a possible calpain-like protein. The gene products showing upregulated expression in PKDL isolates may be candidates playing a role in the altered clinical manifestation in PKDL. Such differentially expressed genes hold the key to understanding the parasite genetic factors that contribute to the persistence after clinical cure of VL.
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Affiliation(s)
- Poonam Salotra
- Molecular Biology Laboratory, Institute of Pathology (ICMR), Safdarjung Hospital Campus, New Delhi, India.
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McKerrow JH, Caffrey C, Kelly B, Loke P, Sajid M. PROTEASES IN PARASITIC DISEASES. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2006; 1:497-536. [PMID: 18039124 DOI: 10.1146/annurev.pathol.1.110304.100151] [Citation(s) in RCA: 281] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- James H. McKerrow
- Department of Pathology and the Sandler Center, University of California, San Francisco, San Francisco, California 94143; , , ,
| | - Conor Caffrey
- Department of Pathology and the Sandler Center, University of California, San Francisco, San Francisco, California 94143; , , ,
| | - Ben Kelly
- Department of Pathology and the Sandler Center, University of California, San Francisco, San Francisco, California 94143; , , ,
| | - P'ng Loke
- Department of Pathology and the Sandler Center, University of California, San Francisco, San Francisco, California 94143; , , ,
| | - Mohammed Sajid
- Department of Pathology and the Sandler Center, University of California, San Francisco, San Francisco, California 94143; , , ,
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Yao C, Luo J, Hsiao C, Donelson JE, Wilson ME. Internal and surface subpopulations of the major surface protease (MSP) of Leishmania chagasi. Mol Biochem Parasitol 2005; 139:173-83. [PMID: 15664652 DOI: 10.1016/j.molbiopara.2004.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2004] [Revised: 10/19/2004] [Accepted: 11/03/2004] [Indexed: 11/21/2022]
Abstract
Major surface protease (MSP) facilitates Leishmania promastigote evasion of complement-mediated lysis in the mammalian host and enhances host macrophage phagocytosis of the promastigotes. We previously showed that the steady-state abundance of MSP protein increases 14-fold during in vitro cultivation of L. chagasi promastigotes from logarithmic to stationary phase, despite the fact that the total amount of MSP mRNA does not increase. Furthermore, 10 major MSP isoforms are differentially expressed in different promastigote growth phases, and attenuation of parasites by long-term in vitro cultivation influences MSP isoform expression. Herein, we report that although about two-thirds of newly synthesized MSP becomes surface localized, the rest of the MSP does not reach the promastigote surface. This internal MSP is stable without detectable decrease in abundance up to 6 days after biosynthesis. Furthermore, surface-localized MSP is released at different rates from logarithmic and stationary phase virulent Leishmania promastigotes. These data are consistent with the hypothesis that the major mechanism regulating MSP abundance is the rate of loss of surface-localized MSP from the promastigote surface, and that internally localized MSP is very stable.
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Affiliation(s)
- Chaoqun Yao
- VA Medical Center, University of Iowa, Iowa City, IA 52242, USA.
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