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Reers AB, Bautista R, McLellan J, Morales B, Garza R, Bol S, Hanson KK, Bunnik EM. Histone modification analysis reveals common regulators of gene expression in liver and blood stage merozoites of Plasmodium parasites. Epigenetics Chromatin 2023; 16:25. [PMID: 37322481 PMCID: PMC10268464 DOI: 10.1186/s13072-023-00500-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 06/06/2023] [Indexed: 06/17/2023] Open
Abstract
Gene expression in malaria parasites is subject to various layers of regulation, including histone post-translational modifications (PTMs). Gene regulatory mechanisms have been extensively studied during the main developmental stages of Plasmodium parasites inside erythrocytes, from the ring stage following invasion to the schizont stage leading up to egress. However, gene regulation in merozoites that mediate the transition from one host cell to the next is an understudied area of parasite biology. Here, we sought to characterize gene expression and the corresponding histone PTM landscape during this stage of the parasite lifecycle through RNA-seq and ChIP-seq on P. falciparum blood stage schizonts, merozoites, and rings, as well as P. berghei liver stage merozoites. In both hepatic and erythrocytic merozoites, we identified a subset of genes with a unique histone PTM profile characterized by a region of H3K4me3 depletion in their promoter. These genes were upregulated in hepatic and erythrocytic merozoites and rings, had roles in protein export, translation, and host cell remodeling, and shared a DNA motif. These results indicate that similar regulatory mechanisms may underlie merozoite formation in the liver and blood stages. We also observed that H3K4me2 was deposited in gene bodies of gene families encoding variant surface antigens in erythrocytic merozoites, which may facilitate switching of gene expression between different members of these families. Finally, H3K18me and H2K27me were uncoupled from gene expression and were enriched around the centromeres in erythrocytic schizonts and merozoites, suggesting potential roles in the maintenance of chromosomal organization during schizogony. Together, our results demonstrate that extensive changes in gene expression and histone landscape occur during the schizont-to-ring transition to facilitate productive erythrocyte infection. The dynamic remodeling of the transcriptional program in hepatic and erythrocytic merozoites makes this stage attractive as a target for novel anti-malarial drugs that may have activity against both the liver and blood stages.
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Affiliation(s)
- Ashley B Reers
- Department of Microbiology, Immunology, and Molecular Genetics, Long School of Medicine, University of Texas Health Science Center, San Antonio, TX, USA
| | - Rodriel Bautista
- Department of Microbiology, Immunology, and Molecular Genetics, Long School of Medicine, University of Texas Health Science Center, San Antonio, TX, USA
| | - James McLellan
- Department of Molecular Microbiology and Immunology and South Texas Center for Emerging Infectious Diseases, University of Texas San Antonio, San Antonio, TX, USA
| | - Beatriz Morales
- Department of Molecular Microbiology and Immunology and South Texas Center for Emerging Infectious Diseases, University of Texas San Antonio, San Antonio, TX, USA
| | - Rolando Garza
- Department of Microbiology, Immunology, and Molecular Genetics, Long School of Medicine, University of Texas Health Science Center, San Antonio, TX, USA
| | - Sebastiaan Bol
- Department of Microbiology, Immunology, and Molecular Genetics, Long School of Medicine, University of Texas Health Science Center, San Antonio, TX, USA
| | - Kirsten K Hanson
- Department of Molecular Microbiology and Immunology and South Texas Center for Emerging Infectious Diseases, University of Texas San Antonio, San Antonio, TX, USA
| | - Evelien M Bunnik
- Department of Microbiology, Immunology, and Molecular Genetics, Long School of Medicine, University of Texas Health Science Center, San Antonio, TX, USA.
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Parres-Mercader M, Pance A, Gómez-Díaz E. Novel systems to study vector-pathogen interactions in malaria. Front Cell Infect Microbiol 2023; 13:1146030. [PMID: 37305421 PMCID: PMC10253182 DOI: 10.3389/fcimb.2023.1146030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 04/04/2023] [Indexed: 06/13/2023] Open
Abstract
Some parasitic diseases, such as malaria, require two hosts to complete their lifecycle: a human and an insect vector. Although most malaria research has focused on parasite development in the human host, the life cycle within the vector is critical for the propagation of the disease. The mosquito stage of the Plasmodium lifecycle represents a major demographic bottleneck, crucial for transmission blocking strategies. Furthermore, it is in the vector, where sexual recombination occurs generating "de novo" genetic diversity, which can favor the spread of drug resistance and hinder effective vaccine development. However, understanding of vector-parasite interactions is hampered by the lack of experimental systems that mimic the natural environment while allowing to control and standardize the complexity of the interactions. The breakthrough in stem cell technologies has provided new insights into human-pathogen interactions, but these advances have not been translated into insect models. Here, we review in vivo and in vitro systems that have been used so far to study malaria in the mosquito. We also highlight the relevance of single-cell technologies to progress understanding of these interactions with higher resolution and depth. Finally, we emphasize the necessity to develop robust and accessible ex vivo systems (tissues and organs) to enable investigation of the molecular mechanisms of parasite-vector interactions providing new targets for malaria control.
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Affiliation(s)
- Marina Parres-Mercader
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas (IPBLN, CSIC), Granada, Spain
| | - Alena Pance
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield, United Kingdom
| | - Elena Gómez-Díaz
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas (IPBLN, CSIC), Granada, Spain
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Hussien MI, Soliman BA, Tewfick MK, O’Brochta DA. An ex vivo system for investigation of Plasmodium berghei invasion of the salivary gland of Anopheles stephensi mosquitoes. Pathog Glob Health 2023; 117:308-314. [PMID: 35993325 PMCID: PMC10081056 DOI: 10.1080/20477724.2022.2108647] [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] [Indexed: 10/15/2022] Open
Abstract
Plasmodium sporozoites associated with the midgut and in the hemolymph of mosquitoes differ from sporozoites in the secretory cavities and ducts of the insects' salivary glands in their transcriptome, proteome, motility, and infectivity. Using an ex vivo Anopheles stephensi salivary gland culture system incorporating simple microfluidics and transgenic Plasmodium berghei with the fluorescent protein gene mCherry under the transcriptional control of the Pbuis4 promoter whose expression served as a proxy for parasite maturation, we observed rapid parasite maturation in the absence of salivary gland invasion. While in vivo Pbuis4::mCherry expression was only detectable in sporozoites within the salivary glands (mature parasites) as expected, the simple exposure of P. berghei sporozoites to dissected salivary glands led to rapid parasite maturation as indicated by mCherry expression. These results suggest that previous efforts to develop ex vivo and in vitro systems for investigating sporozoite interactions with mosquito salivary glands have likely been unsuccessful in part because the maturation of sporozoites leads to a loss in the ability to invade salivary glands.
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Affiliation(s)
- Mai I. Hussien
- Insect Transformation Facility, Institute for Bioscience and Biotechnology Research, University of Maryland-College Park, Rockville, MD, USA
- Department of Zoology, Faculty of Science, Suez University, Suez, Egypt
| | - Belal A. Soliman
- Department of Zoology, Faculty of Science, Suez University, Suez, Egypt
| | - Maha K. Tewfick
- Department of Zoology, Faculty of Science, Suez University, Suez, Egypt
| | - David A. O’Brochta
- Insect Transformation Facility, Institute for Bioscience and Biotechnology Research, University of Maryland-College Park, Rockville, MD, USA
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Pathak AK, Shiau JC, Franke-Fayard B, Shollenberger LM, Harn DA, Kyle DE, Murdock CC. Streamlining sporozoite isolation from mosquitoes by leveraging the dynamics of migration to the salivary glands. Malar J 2022; 21:264. [PMID: 36100902 PMCID: PMC9472382 DOI: 10.1186/s12936-022-04270-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 08/12/2022] [Indexed: 12/05/2022] Open
Abstract
Background Sporozoites isolated from the salivary glands of Plasmodium-infected mosquitoes are a prerequisite for several basic and pre-clinical applications. Although salivary glands are pooled to maximize sporozoite recovery, insufficient yields pose logistical and analytical hurdles; thus, predicting yields prior to isolation would be valuable. Preceding oocyst densities in the midgut is an obvious candidate. However, it is unclear whether current understanding of its relationship with sporozoite densities can be used to maximize yields, or whether it can capture the potential density-dependence in rates of sporozoite invasion of the salivary glands. Methods This study presents a retrospective analysis of Anopheles stephensi mosquitoes infected with two strains of the rodent-specific Plasmodium berghei. Mean oocyst densities were estimated in the midguts earlier in the infection (11–15 days post-blood meal), with sporozoites pooled from the salivary glands later in the infection (17–29 days). Generalized linear mixed effects models were used to determine if (1) mean oocyst densities can predict sporozoite yields from pooled salivary glands, (2) whether these densities can capture differences in rates of sporozoite invasion of salivary glands, and (3), if the interaction between oocyst densities and time could be leveraged to boost overall yields. Results The non-linear effect of mean oocyst densities confirmed the role of density-dependent constraints in limiting yields beyond certain oocyst densities. Irrespective of oocyst densities however, the continued invasion of salivary glands by the sporozoites boosted recoveries over time (17–29 days post-blood meal) for either parasite strain. Conclusions Sporozoite invasion of the salivary glands over time can be leveraged to maximize yields for P. berghei. In general, however, invasion of the salivary glands over time is a critical fitness determinant for all Plasmodium species (extrinsic incubation period, EIP). Thus, delaying sporozoite collection could, in principle, substantially reduce dissection effort for any parasite within the genus, with the results also alluding to the potential for changes in sporozoites densities over time to modify infectivity for the next host. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04270-y.
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Ukawuba I, Shaman J. Inference and dynamic simulation of malaria using a simple climate-driven entomological model of malaria transmission. PLoS Comput Biol 2022; 18:e1010161. [PMID: 35679241 PMCID: PMC9182318 DOI: 10.1371/journal.pcbi.1010161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/02/2022] [Indexed: 12/02/2022] Open
Abstract
Given the crucial role of climate in malaria transmission, many mechanistic models of malaria represent vector biology and the parasite lifecycle as functions of climate variables in order to accurately capture malaria transmission dynamics. Lower dimension mechanistic models that utilize implicit vector dynamics have relied on indirect climate modulation of transmission processes, which compromises investigation of the ecological role played by climate in malaria transmission. In this study, we develop an implicit process-based malaria model with direct climate-mediated modulation of transmission pressure borne through the Entomological Inoculation Rate (EIR). The EIR, a measure of the number of infectious bites per person per unit time, includes the effects of vector dynamics, resulting from mosquito development, survivorship, feeding activity and parasite development, all of which are moderated by climate. We combine this EIR-model framework, which is driven by rainfall and temperature, with Bayesian inference methods, and evaluate the model’s ability to simulate local transmission across 42 regions in Rwanda over four years. Our findings indicate that the biologically-motivated, EIR-model framework is capable of accurately simulating seasonal malaria dynamics and capturing of some of the inter-annual variation in malaria incidence. However, the model unsurprisingly failed to reproduce large declines in malaria transmission during 2018 and 2019 due to elevated anti-malaria measures, which were not accounted for in the model structure. The climate-driven transmission model also captured regional variation in malaria incidence across Rwanda’s diverse climate, while identifying key entomological and epidemiological parameters important to seasonal malaria dynamics. In general, this new model construct advances the capabilities of implicitly-forced lower dimension dynamical malaria models by leveraging climate drivers of malaria ecology and transmission. Climate plays a fundamental and complex role in malaria transmission, by acting on multiple aspects of mosquito ecology and parasite transmissibility. However, to express malaria transmission pressure, malaria models with implicit vector dynamics have relied on indirect predictors of vector ecology, such as temporal seasonality or interpolations of rainfall/temperature, instead of entomological processes directly informed by ambient conditions. This approach obscures the specific influence of environmental conditions on relevant vector and parasite ecology, as well as meaningful interpretation of climate variability within these models. Here, we demonstrate that both interpretability and ecological effect from climate can be instantiated in lower dimension dynamical models through representation of transmission pressures via a climate-driven Entomological Inoculation Rate (EIR). This process-based model framework is driven by local rainfall and temperature, which regulate multiple aspects of the EIR, namely mosquito density, host-seeking activity, and parasite infectivity. Our results indicate that the climate-driven model construct is able to reproduce regional and local malaria transmission at seasonal and inter-annual time scales, while enabling identification of key entomological determinants of transmission.
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Affiliation(s)
- Israel Ukawuba
- Columbia University, Mailman School of Public Health, New York, New York, United States of America
- * E-mail:
| | - Jeffrey Shaman
- Columbia University, Mailman School of Public Health, New York, New York, United States of America
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6
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Blight J, Sala KA, Atcheson E, Kramer H, El-Turabi A, Real E, Dahalan FA, Bettencourt P, Dickinson-Craig E, Alves E, Salman AM, Janse CJ, Ashcroft FM, Hill AV, Reyes-Sandoval A, Blagborough AM, Baum J. Dissection-independent production of Plasmodium sporozoites from whole mosquitoes. Life Sci Alliance 2021; 4:e202101094. [PMID: 34135099 PMCID: PMC8321652 DOI: 10.26508/lsa.202101094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 01/05/2023] Open
Abstract
Progress towards a protective vaccine against malaria remains slow. To date, only limited protection has been routinely achieved following immunisation with either whole-parasite (sporozoite) or subunit-based vaccines. One major roadblock to vaccine progress, and to pre-erythrocytic parasite biology in general, is the continued reliance on manual salivary gland dissection for sporozoite isolation from infected mosquitoes. Here, we report development of a multi-step method, based on batch processing of homogenised whole mosquitoes, slurry, and density-gradient filtration, which combined with free-flow electrophoresis rapidly produces a pure, infective sporozoite inoculum. Human-infective Plasmodium falciparum and rodent-infective Plasmodium berghei sporozoites produced in this way are two- to threefold more infective than salivary gland dissection sporozoites in in vitro hepatocyte infection assays. In an in vivo rodent malaria model, the same P. berghei sporozoites confer sterile protection from mosquito-bite challenge when immunisation is delivered intravenously or 60-70% protection when delivered intramuscularly. By improving purity, infectivity, and immunogenicity, this method represents a key advancement in capacity to produce research-grade sporozoites, which should impact delivery of a whole-parasite based malaria vaccine at scale in the future.
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Affiliation(s)
- Joshua Blight
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, UK
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Katarzyna A Sala
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, UK
| | - Erwan Atcheson
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Holger Kramer
- Department of Physiology, Anatomy and Genetics, Henry Wellcome Building for Gene Function, University of Oxford, Oxford, UK
- Medical Research Council London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK
| | - Aadil El-Turabi
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Eliana Real
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, UK
| | - Farah A Dahalan
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, UK
| | - Paulo Bettencourt
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Emma Dickinson-Craig
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Eduardo Alves
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Ahmed M Salman
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Chris J Janse
- Department of Parasitology, Leiden Malaria Research Group, Center of Infectious Diseases, Leiden University Medical Center, (LUMC, L4-Q), Leiden, The Netherlands
| | - Frances M Ashcroft
- Department of Physiology, Anatomy and Genetics, Henry Wellcome Building for Gene Function, University of Oxford, Oxford, UK
| | - Adrian Vs Hill
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Arturo Reyes-Sandoval
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
- Instituto Politécnico Nacional, Mexico City, Mexico
| | - Andrew M Blagborough
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, UK
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Jake Baum
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, UK
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Singer M, Frischknecht F. Fluorescent tagging of Plasmodium circumsporozoite protein allows imaging of sporozoite formation but blocks egress from oocysts. Cell Microbiol 2021; 23:e13321. [PMID: 33600048 DOI: 10.1111/cmi.13321] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/10/2021] [Accepted: 02/16/2021] [Indexed: 01/23/2023]
Abstract
The circumsporozoite protein, CSP, is the major surface protein of Plasmodium sporozoites, the form of malaria parasites transmitted by mosquitoes. CSP is involved in sporozoite formation within and egress from oocysts, entry into mosquito salivary glands and mammalian liver as well as migration in the skin. Yet, how CSP facilitates sporozoite formation, oocyst egress and hepatocyte specific invasion is still not fully understood. Here, we aimed at generating a series of parasites expressing full-length versions of CSP with internally inserted green fluorescent protein between known domains at the endogenous csp locus. This enabled the investigation of sporozoite formation in living oocysts. GFP insertion after the signal peptide leads to cleavage of GFP before the fusion protein reached the plasma membrane while insertion of GFP before or after the TSR domain prevented sporozoite egress and liver invasion. These data suggest different strategies for obtaining mature salivary gland sporozoites that express GFP-CSP fusions.
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Affiliation(s)
- Mirko Singer
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
- Experimental Parasitology, Department for Veterinary Sciences, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
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Bogale HN, Pascini TV, Kanatani S, Sá JM, Wellems TE, Sinnis P, Vega-Rodríguez J, Serre D. Transcriptional heterogeneity and tightly regulated changes in gene expression during Plasmodium berghei sporozoite development. Proc Natl Acad Sci U S A 2021; 118:e2023438118. [PMID: 33653959 PMCID: PMC7958459 DOI: 10.1073/pnas.2023438118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Despite the critical role of Plasmodium sporozoites in malaria transmission, we still know little about the mechanisms underlying their development in mosquitoes. Here, we use single-cell RNA sequencing to characterize the gene expression profiles of 16,038 Plasmodium berghei sporozoites isolated throughout their development from midgut oocysts to salivary glands, and from forced salivation experiments. Our results reveal a succession of tightly regulated changes in gene expression occurring during the maturation of sporozoites and highlight candidate genes that could play important roles in oocyst egress, sporozoite motility, and the mechanisms underlying the invasion of mosquito salivary glands and mammalian hepatocytes. In addition, the single-cell data reveal extensive transcriptional heterogeneity among parasites isolated from the same anatomical site, suggesting that Plasmodium development in mosquitoes is asynchronous and regulated by intrinsic as well as environmental factors. Finally, our analyses show a decrease in transcriptional activity preceding the translational repression observed in mature sporozoites and associated with their quiescent state in salivary glands, followed by a rapid reactivation of the transcriptional machinery immediately upon salivation.
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Affiliation(s)
- Haikel N Bogale
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Tales V Pascini
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Sachie Kanatani
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Juliana M Sá
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Thomas E Wellems
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
| | - Photini Sinnis
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Joel Vega-Rodríguez
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - David Serre
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201;
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201
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Briquet S, Marinach C, Silvie O, Vaquero C. Preparing for Transmission: Gene Regulation in Plasmodium Sporozoites. Front Cell Infect Microbiol 2021; 10:618430. [PMID: 33585284 PMCID: PMC7878544 DOI: 10.3389/fcimb.2020.618430] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/16/2020] [Indexed: 11/13/2022] Open
Abstract
Plasmodium sporozoites are transmitted to mammals by anopheline mosquitoes and first infect the liver, where they transform into replicative exoerythrocytic forms, which subsequently release thousands of merozoites that invade erythrocytes and initiate the malaria disease. In some species, sporozoites can transform into dormant hypnozoites in the liver, which cause malaria relapses upon reactivation. Transmission from the insect vector to a mammalian host is a critical step of the parasite life cycle, and requires tightly regulated gene expression. Sporozoites are formed inside oocysts in the mosquito midgut and become fully infectious after colonization of the insect salivary glands, where they remain quiescent until transmission. Parasite maturation into infectious sporozoites is associated with reprogramming of the sporozoite transcriptome and proteome, which depends on multiple layers of transcriptional and post-transcriptional regulatory mechanisms. An emerging scheme is that gene expression in Plasmodium sporozoites is controlled by alternating waves of transcription activity and translational repression, which shape the parasite RNA and protein repertoires for successful transition from the mosquito vector to the mammalian host.
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Affiliation(s)
- Sylvie Briquet
- Centre d'Immunologie et des Maladies Infectieuses, INSERM, CNRS, Sorbonne Université, Paris, France
| | - Carine Marinach
- Centre d'Immunologie et des Maladies Infectieuses, INSERM, CNRS, Sorbonne Université, Paris, France
| | - Olivier Silvie
- Centre d'Immunologie et des Maladies Infectieuses, INSERM, CNRS, Sorbonne Université, Paris, France
| | - Catherine Vaquero
- Centre d'Immunologie et des Maladies Infectieuses, INSERM, CNRS, Sorbonne Université, Paris, France
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Kumari S, Chauhan C, Tevatiya S, Singla D, De TD, Sharma P, Thomas T, Rani J, Savargaonkar D, Pandey KC, Pande V, Dixit R. Genetic changes of Plasmodium vivax tempers host tissue-specific responses in Anopheles stephensi. CURRENT RESEARCH IN IMMUNOLOGY 2021; 2:12-22. [PMID: 35492403 PMCID: PMC9040150 DOI: 10.1016/j.crimmu.2021.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 01/13/2021] [Accepted: 02/14/2021] [Indexed: 02/02/2023] Open
Abstract
Recently, we showed how an early restriction of gut flora proliferation by Plasmodium vivax favors immune-suppression and Plasmodium survival in the gut lumen (Sharma et al., 2020). Here, we asked post gut invasion how P. vivax interacts with individual tissues such as the midgut, hemocyte, and salivary glands, and manages its survival in the mosquito host. Our data from tissue-specific comparative RNA-Seq analysis and extensive temporal/spatial expression profiling of selected mosquito transcripts in the uninfected and P. vivax infected mosquito’s tissues indicated that (i) a transient suppression of gut metabolic machinery by early oocysts; (ii) enriched expression of nutritional responsive proteins and immune proteins against late oocysts, together may ensure optimal parasite development and gut homeostasis restoration; (iii) pre-immune activation of hemocyte by early gut-oocysts infection via REL induction (p < 0.003); and altered expression of hemocyte-encoded immune proteins may cause rapid removal of free circulating sporozoites from hemolymph; (iv) while a strong suppression of salivary metabolic activities, and elevated expression of salivary specific secretory, as well as immune proteins together, may favor the long-term storage and survival of invaded sporozoites. Finally, our RNA-Seq-based discovery of 4449 transcripts of Plasmodium vivax origin, and their developmental stage-specific expression modulation in the corresponding infected mosquito tissues, predicts a possible mechanism of mosquito responses evasion by P. vivax. Conclusively, our system-wide RNA-Seq analysis provides the first genetic evidence of direct mosquito-Plasmodium interaction and establishes a functional correlation. System-wide RNASeq analysis discloses direct mosquito-Plasmodium vivax interaction and establishes a functional correlation. Discovery of 4449 transcripts specific to P. vivax developmental stages sheds light on possible immune evasion mechanisms. Upregulation of nutritional related transcripts ensures optimal late oocyst development and midgut homeostasis. Hemocyte activation by early oocysts ensure removal of free circulatory sporozoites by proliferating immune transcripts. Heightened levels of salivary immune transcripts show that an active local immune response restricts salivary invaded sporozoite
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Kumari S, Chauhan C, Tevatiya S, Singla D, De TD, Sharma P, Thomas T, Rani J, Savargaonkar D, Pandey KC, Pande V, Dixit R. Genetic changes of Plasmodium vivax tempers host tissue-specific responses in Anopheles stephensi. CURRENT RESEARCH IN IMMUNOLOGY 2021. [DOI: https:/doi.org/10.1016/j.crimmu.2021.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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12
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Kumari S, Chauhan C, Tevatiya S, Singla D, De TD, Sharma P, Thomas T, Rani J, Savargaonkar D, Pandey KC, Pande V, Dixit R. Genetic changes of Plasmodium vivax tempers host tissue-specific responses in Anopheles stephensi. CURRENT RESEARCH IN IMMUNOLOGY 2021. [DOI: https://doi.org/10.1016/j.crimmu.2021.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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13
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Sato Y, Ries S, Stenzel W, Fillatreau S, Matuschewski K. The Liver-Stage Plasmodium Infection Is a Critical Checkpoint for Development of Experimental Cerebral Malaria. Front Immunol 2019; 10:2554. [PMID: 31736970 PMCID: PMC6837997 DOI: 10.3389/fimmu.2019.02554] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 10/15/2019] [Indexed: 12/20/2022] Open
Abstract
Cerebral malaria is a life-threatening complication of malaria in humans, and the underlying pathogenic mechanisms are widely analyzed in a murine model of experimental cerebral malaria (ECM). Here, we show abrogation of ECM by hemocoel sporozoite-induced infection of a transgenic Plasmodium berghei line that overexpresses profilin, whereas these parasites remain fully virulent in transfusion-mediated blood infection. We, thus, demonstrate the importance of the clinically silent liver-stage infection for modulating the onset of ECM. Even though both parasites triggered comparable splenic immune cell expansion and accumulation of antigen-experienced CD8+ T cells in the brain, infection with transgenic sporozoites did not lead to cerebral vascular damages and suppressed the recruitment of overall lymphocyte populations. Strikingly, infection with the transgenic strain led to maintenance of CD115+Ly6C+ monocytes, which disappear in infected animals prone to ECM. An early induction of IL-10, IL-12p70, IL-6, and TNF at the time when parasites emerge from the liver might lead to a diminished induction of hepatic immunity. Collectively, our study reveals the essential role of early host interactions in the liver that may dampen the subsequent pro-inflammatory immune responses and influence the occurrence of ECM, highlighting a novel checkpoint in this fatal pathology.
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Affiliation(s)
- Yuko Sato
- Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany.,Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo, Japan
| | - Stefanie Ries
- Immune Regulation Research Group, Deutsches Rheuma-Forschungszentrum, Berlin, Germany
| | - Werner Stenzel
- Department of Neuropathology, Charité - Universitätmedizin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Berlin, Germany
| | - Simon Fillatreau
- Immune Regulation Research Group, Deutsches Rheuma-Forschungszentrum, Berlin, Germany.,Department of Immunology, Infectiology and Haematology (I2H), Institut Necker-Enfants Malades, INSERM U1151-CNRS UMR 8253, Paris, France.,Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,AP-HP, Hôpital Necker Enfants Malades, Paris, France
| | - Kai Matuschewski
- Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany.,Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, Germany
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14
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Transcriptomics and proteomics reveal two waves of translational repression during the maturation of malaria parasite sporozoites. Nat Commun 2019; 10:4964. [PMID: 31673027 PMCID: PMC6823429 DOI: 10.1038/s41467-019-12936-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 10/09/2019] [Indexed: 02/08/2023] Open
Abstract
Plasmodium sporozoites are transmitted from infected mosquitoes to mammals, and must navigate the host skin and vasculature to infect the liver. This journey requires distinct proteomes. Here, we report the dynamic transcriptomes and proteomes of both oocyst sporozoites and salivary gland sporozoites in both rodent-infectious Plasmodium yoelii parasites and human-infectious Plasmodium falciparum parasites. The data robustly define mRNAs and proteins that are upregulated in oocyst sporozoites (UOS) or upregulated in infectious sporozoites (UIS) within the salivary glands, including many that are essential for sporozoite functions in the vector and host. Moreover, we find that malaria parasites use two overlapping, extensive, and independent programs of translational repression across sporozoite maturation to temporally regulate protein expression. Together with gene-specific validation experiments, these data indicate that two waves of translational repression are implemented and relieved at different times during sporozoite maturation, migration and infection, thus promoting their successful development and vector-to-host transition. Here, the authors report transcriptomes and proteomes of oocyst sporozoite and salivary gland sporozoite stages in rodent-infectious Plasmodium yoelii parasites and human infectious Plasmodium falciparum parasites and define two waves of translational repression during sporozoite maturation.
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15
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Wells MB, Andrew DJ. Anopheles Salivary Gland Architecture Shapes Plasmodium Sporozoite Availability for Transmission. mBio 2019; 10:e01238-19. [PMID: 31387905 PMCID: PMC6686039 DOI: 10.1128/mbio.01238-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/11/2019] [Indexed: 12/18/2022] Open
Abstract
Plasmodium sporozoites (SPZs) must traverse the mosquito salivary glands (SGs) to reach a new vertebrate host and continue the malaria disease cycle. Although SGs can harbor thousands of sporozoites, only 10 to 100 are deposited into a host during probing. To determine how the SGs might function as a bottleneck in SPZ transmission, we have characterized Anopheles stephensi SGs infected with the rodent malaria parasite Plasmodium berghei using immunofluorescence confocal microscopy. Our analyses corroborate findings from previous electron microscopy studies and provide new insights into the invasion process. We identified sites of SPZ accumulation within SGs across a range of infection intensities. Although SPZs were most often seen in the distal lateral SG lobes, they were also observed in the medial and proximal lateral lobes. Most parasites were associated with either the basement membrane or secretory cavities. SPZs accumulated at physical barriers, including fused salivary ducts and extensions of the chitinous salivary duct wall into the distal lumen. SPZs were observed only rarely within salivary ducts. SPZs appeared to contact each other in many different quantities, not just in the previously described large bundles. Within parasite bundles, all of the SPZs were oriented in the same direction. We found that moderate levels of infection did not necessarily correlate with major SG disruptions or abundant SG cell death. Altogether, our findings suggest that SG architecture largely acts as a barrier to SPZ transmission.IMPORTANCE Malaria continues to have a devastating impact on human health. With growing resistance to insecticides and antimalarial drugs, as well as climate change predictions indicating expansion of vector territories, the impact of malaria is likely to increase. Additional insights regarding pathogen migration through vector mosquitoes are needed to develop novel methods to prevent transmission to new hosts. Pathogens, including the microbes that cause malaria, must invade the salivary glands (SGs) for transmission. Since SG traversal is required for parasite transmission, SGs are ideal targets for transmission-blocking strategies. The work presented here highlights the role that mosquito SG architecture plays in limiting parasite traversal, revealing how the SG transmission bottleneck is imposed. Further, our data provide unprecedented detail about SG-sporozoite interactions and gland-to-gland variation not provided in previous studies.
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Affiliation(s)
- Michael B Wells
- Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Deborah J Andrew
- Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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16
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Bantuchai S, Nozaki M, Thongkukiatkul A, Lorsuwannarat N, Tachibana M, Baba M, Matsuoka K, Tsuboi T, Torii M, Ishino T. Rhoptry neck protein 11 has crucial roles during malaria parasite sporozoite invasion of salivary glands and hepatocytes. Int J Parasitol 2019; 49:725-735. [DOI: 10.1016/j.ijpara.2019.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 03/29/2019] [Accepted: 05/03/2019] [Indexed: 12/01/2022]
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17
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Dundas K, Shears MJ, Sinnis P, Wright GJ. Important Extracellular Interactions between Plasmodium Sporozoites and Host Cells Required for Infection. Trends Parasitol 2018; 35:129-139. [PMID: 30583849 DOI: 10.1016/j.pt.2018.11.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/22/2018] [Accepted: 11/26/2018] [Indexed: 01/08/2023]
Abstract
Malaria is an infectious disease, caused by Plasmodium parasites, that remains a major global health problem. Infection begins when salivary gland sporozoites are transmitted through the bite of an infected mosquito. Once within the host, sporozoites navigate through the dermis, into the bloodstream, and eventually invade hepatocytes. While we have an increasingly sophisticated cellular description of this journey, our molecular understanding of the extracellular interactions between the sporozoite and mammalian host that regulate migration and invasion remain comparatively poor. Here, we review the current state of our understanding, highlight the technical limitations that have frustrated progress, and outline how new approaches will help to address this knowledge gap with the ultimate aim of improving malaria treatments.
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Affiliation(s)
- Kirsten Dundas
- Cell Surface Signalling Laboratory and Parasites and Microbes Programme, Wellcome Trust Sanger Institute, Cambridge, CB10 1SA, UK
| | - Melanie J Shears
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Photini Sinnis
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Gavin J Wright
- Cell Surface Signalling Laboratory and Parasites and Microbes Programme, Wellcome Trust Sanger Institute, Cambridge, CB10 1SA, UK.
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18
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Swearingen KE, Lindner SE. Plasmodium Parasites Viewed through Proteomics. Trends Parasitol 2018; 34:945-960. [PMID: 30146456 PMCID: PMC6204299 DOI: 10.1016/j.pt.2018.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 08/02/2018] [Accepted: 08/05/2018] [Indexed: 12/14/2022]
Abstract
Early sequencing efforts that produced the genomes of several species of malaria parasites (Plasmodium genus) propelled transcriptomic and proteomic efforts. In this review, we focus upon some of the exciting proteomic advances from studies of Plasmodium parasites over approximately the past decade. With improvements to both instrumentation and data-processing capabilities, long-standing questions about the forms and functions of these important pathogens are rapidly being answered. In particular, global and subcellular proteomics, quantitative proteomics, and the detection of post-translational modifications have all revealed important features of the parasite's regulatory mechanisms. Finally, we provide our perspectives on future applications of proteomics to Plasmodium research, as well as suggestions for further improvement through standardization of data deposition, analysis, and accessibility.
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Affiliation(s)
- Kristian E Swearingen
- Institute for Systems Biology, Seattle, WA 98109, USA; Center for Infectious Disease Research, Seattle, WA 98109, USA
| | - Scott E Lindner
- Department of Biochemistry and Molecular Biology, Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA.
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19
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Klug D, Kehrer J, Frischknecht F, Singer M. A synthetic promoter for multi-stage expression to probe complementary functions of Plasmodium adhesins. J Cell Sci 2018; 131:jcs.210971. [PMID: 30237220 DOI: 10.1242/jcs.210971] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 09/10/2018] [Indexed: 11/20/2022] Open
Abstract
Gene expression of malaria parasites is mediated by the apicomplexan Apetala2 (ApiAP2) transcription factor family. Different ApiAP2s control gene expression at distinct stages in the complex life cycle of the parasite, ensuring timely expression of stage-specific genes. ApiAP2s recognize short cis-regulatory elements that are enriched in the upstream/promoter region of their target genes. This should, in principle, allow the generation of 'synthetic' promoters that drive gene expression at desired stages of the Plasmodium life cycle. Here we test this concept by combining cis-regulatory elements of two genes expressed successively within the mosquito part of the life cycle. Our tailored 'synthetic' promoters, named Spooki 1.0 and Spooki 2.0, activate gene expression in early and late mosquito stages, as shown by the expression of a fluorescent reporter. We used these promoters to address the specific functionality of two related adhesins that are exclusively expressed either during the early or late mosquito stage. By modifying the expression profile of both adhesins in absence of their counterpart we were able to test for complementary functions in gliding and invasion. We discuss the possible advantages and drawbacks of our approach.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Dennis Klug
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Jessica Kehrer
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Mirko Singer
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
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20
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Costa G, Gildenhard M, Eldering M, Lindquist RL, Hauser AE, Sauerwein R, Goosmann C, Brinkmann V, Carrillo-Bustamante P, Levashina EA. Non-competitive resource exploitation within mosquito shapes within-host malaria infectivity and virulence. Nat Commun 2018; 9:3474. [PMID: 30150763 PMCID: PMC6110728 DOI: 10.1038/s41467-018-05893-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Accepted: 08/01/2018] [Indexed: 11/22/2022] Open
Abstract
Malaria is a fatal human parasitic disease transmitted by a mosquito vector. Although the evolution of within-host malaria virulence has been the focus of many theoretical and empirical studies, the vector’s contribution to this process is not well understood. Here, we explore how within-vector resource exploitation would impact the evolution of within-host Plasmodium virulence. By combining within-vector dynamics and malaria epidemiology, we develop a mathematical model, which predicts that non-competitive parasitic resource exploitation within-vector restricts within-host parasite virulence. To validate our model, we experimentally manipulate mosquito lipid trafficking and gauge within-vector parasite development and within-host infectivity and virulence. We find that mosquito-derived lipids determine within-host parasite virulence by shaping development (quantity) and metabolic activity (quality) of transmissible sporozoites. Our findings uncover the potential impact of within-vector environment and vector control strategies on the evolution of malaria virulence. The evolution of within-host malaria virulence has been studied, but the vector’s contribution isn’t well understood. Here, Costa et al. show that non-competitive parasitic resource exploitation within-vector, in particular lipid trafficking, restricts within-host infectivity and virulence of the parasite.
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Affiliation(s)
- G Costa
- Vector Biology Unit, Max Planck Institute for Infection Biology (MPIIB), 10117, Berlin, Germany
| | - M Gildenhard
- Vector Biology Unit, Max Planck Institute for Infection Biology (MPIIB), 10117, Berlin, Germany
| | - M Eldering
- Vector Biology Unit, Max Planck Institute for Infection Biology (MPIIB), 10117, Berlin, Germany.,Department of Medical Microbiology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - R L Lindquist
- Immunodynamics, German Rheumatism Research Centre (DRFZ), 10117, Berlin, Germany
| | - A E Hauser
- Immunodynamics, German Rheumatism Research Centre (DRFZ), 10117, Berlin, Germany.,Immune Dynamics and Intravital Microscopy, Charité-Universitätsmedizin, 10117, Berlin, Germany
| | - R Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - C Goosmann
- Microscopy Core Facility, Max Planck Institute for Infection Biology (MPIIB), 10117, Berlin, Germany
| | - V Brinkmann
- Microscopy Core Facility, Max Planck Institute for Infection Biology (MPIIB), 10117, Berlin, Germany
| | - P Carrillo-Bustamante
- Vector Biology Unit, Max Planck Institute for Infection Biology (MPIIB), 10117, Berlin, Germany
| | - E A Levashina
- Vector Biology Unit, Max Planck Institute for Infection Biology (MPIIB), 10117, Berlin, Germany.
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21
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Singh N, Barnes SJ, Kennedy S, Adams JH. Experimental evaluation of cryopreservative solutions to maintain in vitro and in vivo infectivity of P. berghei sporozoites. PLoS One 2017; 12:e0177304. [PMID: 28531172 PMCID: PMC5439657 DOI: 10.1371/journal.pone.0177304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 04/25/2017] [Indexed: 11/18/2022] Open
Abstract
The rodent malaria parasite Plasmodium berghei is an excellent model organism for laboratory-based experimental evaluation of anti-malarial therapeutics prior to studies with human malaria parasites. The rodent model is especially important for evaluation of pre-erythrocytic (PE) stage therapies, especially as current efforts to develop new PE vaccines and drugs is limited by access to P. falciparum and P. vivax sporozoites. Developing a more effective method for cryopreservation of sporozoites would help improve access to sporozoites for laboratories lacking suitable insectary facilities. In this study, P. berghei GFP-expressing sporozoites were purified from infected mosquitoes by manual dissection of salivary glands and different commercially-available, serum-free cryopreservative solutions were evaluated for efficient cryopreservation of the sporozoites. The cryopreservative solutions evaluated included CryoStor CS2, CryoSolutions DX5, CryoSolutions MC, Hestar 200, Voluven, Hetastarch, and Glycerolyte 57. The viability of fresh and post-thaw cryopreserved sporozoites was determined as a function of the relative sporozoite infectivity by infecting HC-04 cells in vitro, monitoring invasion and growth and development of liver stage parasites. Flow cytometer-based counting provided unbiased and fast quantitative assessment of parasite in vitro infection in infected HC-04 and in vivo infectivity was validated by injecting sporozoites IV into mice. CryoStor CS2 delivered the highest post-thaw recovery and infectivity of cryopreserved sporozoites. Sporozoites cryopreserved in CryoStor CS2 achieved 38% complete development of hepatic stages in HC-04 and 100% infectivity in mice. The cryopreservation method described here demonstrates a viable alternative for fresh Plasmodium sporozoites. The use of cryopreserved sporozoites should facilitate greater access to sporozoites for chemotherapeutic and vaccine research.
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Affiliation(s)
- Naresh Singh
- Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Samantha J. Barnes
- Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Sandra Kennedy
- Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - John H. Adams
- Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
- * E-mail:
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22
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Dunst J, Azzouz N, Liu X, Tsukita S, Seeberger PH, Kamena F. Interaction between Plasmodium Glycosylphosphatidylinositol and the Host Protein Moesin Has No Implication in Malaria Pathology. Front Cell Infect Microbiol 2017; 7:183. [PMID: 28560184 PMCID: PMC5432536 DOI: 10.3389/fcimb.2017.00183] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 04/27/2017] [Indexed: 11/17/2022] Open
Abstract
Glycosylphosphatidylinositol (GPI) anchor of Plasmodium falciparum origin is considered an important toxin leading to severe malaria pathology through stimulation of pro-inflammatory responses from innate immune cells. Even though the GPI-induced immune response is widely described to be mediated by pattern recognition receptors such as TLR2 and TLR4, previous studies have revealed that these two receptors are dispensable for the development of severe malaria pathology. Therefore, this study aimed at the identification of potential alternative Plasmodium GPI receptors. Herein, we have identified the host protein moesin as an interaction partner of Plasmodium GPI in vitro. Given previous reports indicating the relevance of moesin especially in the LPS-mediated induction of pro-inflammatory responses, we have conducted a series of in vitro and in vivo experiments to address the physiological relevance of the moesin-Plasmodium GPI interaction in the context of malaria pathology. We report here that although moesin and Plasmodium GPI interact in vitro, moesin is not critically involved in processes leading to Plasmodium-induced pro-inflammatory immune responses or malaria-associated cerebral pathology.
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Affiliation(s)
- Josefine Dunst
- Institute of Chemistry and Biochemistry, Free University BerlinBerlin, Germany
- Parasitology Unit, Max Planck Institute for Infection BiologyBerlin, Germany
| | - Nahid Azzouz
- Institute of Chemistry and Biochemistry, Free University BerlinBerlin, Germany
- Department of Biomolecular Systems, Max Planck Institute for Colloids and InterfacesPotsdam, Germany
| | - Xinyu Liu
- Department of Chemistry, University of PittsburghPittsburgh, PA, USA
| | - Sachiko Tsukita
- Department of Frontier Biosciences, Graduate School of Frontier Biosciences, Osaka UniversityOsaka, Japan
| | - Peter H. Seeberger
- Institute of Chemistry and Biochemistry, Free University BerlinBerlin, Germany
- Department of Biomolecular Systems, Max Planck Institute for Colloids and InterfacesPotsdam, Germany
| | - Faustin Kamena
- Institute of Chemistry and Biochemistry, Free University BerlinBerlin, Germany
- Parasitology Unit, Max Planck Institute for Infection BiologyBerlin, Germany
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23
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Frischknecht F, Matuschewski K. Plasmodium Sporozoite Biology. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a025478. [PMID: 28108531 DOI: 10.1101/cshperspect.a025478] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Plasmodium sporozoite transmission is a critical population bottleneck in parasite life-cycle progression and, hence, a target for prophylactic drugs and vaccines. The recent progress of a candidate antisporozoite subunit vaccine formulation to licensure highlights the importance of sporozoite transmission intervention in the malaria control portfolio. Sporozoites colonize mosquito salivary glands, migrate through the skin, penetrate blood vessels, breach the liver sinusoid, and invade hepatocytes. Understanding the molecular and cellular mechanisms that mediate the remarkable sporozoite journey in the invertebrate vector and the vertebrate host can inform evidence-based next-generation drug development programs and immune intervention strategies.
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Affiliation(s)
- Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School, 69120 Heidelberg, Germany
| | - Kai Matuschewski
- Department of Molecular Parasitology, Institute of Biology, Humboldt University Berlin, 10115 Berlin, Germany
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24
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Salivary Gland Proteome during Adult Development and after Blood Feeding of Female Anopheles dissidens Mosquitoes (Diptera: Culicidae). PLoS One 2016; 11:e0163810. [PMID: 27669021 PMCID: PMC5036837 DOI: 10.1371/journal.pone.0163810] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 09/14/2016] [Indexed: 12/28/2022] Open
Abstract
Understanding changes in mosquito salivary proteins during the time that sporozoite maturation occurs and after blood feeding may give information regarding the roles of salivary proteins during the malarial transmission. Anopheles dissidens (formerly Anopheles barbirostris species A1) is a potential vector of Plasmodium vivax in Thailand. In this study, analyses of the proteomic profiles of female An. dissidens salivary glands during adult development and after blood feeding were carried out using two-dimensional gel electrophoresis coupled with nano-liquid chromatography-mass spectrometry. Results showed at least 17 major salivary gland proteins present from day one to day 21 post emergence at 8 different time points sampled. Although there was variation observed, the patterns of protein expression could be placed into one of four groups. Fifteen protein spots showed significant depletion after blood feeding with the percentages of the amount of depletion ranging from 8.5% to 68.11%. The overall results identified various proteins, including a putative mucin-like protein, an anti-platelet protein, a long form D7 salivary protein, a putative gVAG protein precursor, a D7-related 3.2 protein, gSG7 salivary proteins, and a gSG6 protein. These results allow better understanding of the changes of the salivary proteins during the adult mosquito development. They also provide candidate proteins to investigate any possible link or not between sporozoite maturation, or survival of skin stage sporozoites, and salivary proteins.
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25
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Hopp CS, Balaban AE, Bushell ESC, Billker O, Rayner JC, Sinnis P. Palmitoyl transferases have critical roles in the development of mosquito and liver stages of Plasmodium. Cell Microbiol 2016; 18:1625-1641. [PMID: 27084458 DOI: 10.1111/cmi.12601] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/24/2016] [Accepted: 04/01/2016] [Indexed: 12/24/2022]
Abstract
As the Plasmodium parasite transitions between mammalian and mosquito host, it has to adjust quickly to new environments. Palmitoylation, a reversible and dynamic lipid post-translational modification, plays a central role in regulating this process and has been implicated with functions for parasite morphology, motility and host cell invasion. While proteins associated with the gliding motility machinery have been described to be palmitoylated, no palmitoyl transferase responsible for regulating gliding motility has previously been identified. Here, we characterize two palmityol transferases with gene tagging and gene deletion approaches. We identify DHHC3, a palmitoyl transferase, as a mediator of ookinete development, with a crucial role for gliding motility in ookinetes and sporozoites, and we co-localize the protein with a marker for the inner membrane complex in the ookinete stage. Ookinetes and sporozoites lacking DHHC3 are impaired in gliding motility and exhibit a strong phenotype in vivo; with ookinetes being significantly less infectious to their mosquito host and sporozoites being non-infectious to mice. Importantly, genetic complementation of the DHHC3-ko parasite completely restored virulence. We generated parasites lacking both DHHC3, as well as the palmitoyl transferase DHHC9, and found an enhanced phenotype for these double knockout parasites, allowing insights into the functional overlap and compensational nature of the large family of PbDHHCs. These findings contribute to our understanding of the organization and mechanism of the gliding motility machinery, which as is becoming increasingly clear, is mediated by palmitoylation.
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Affiliation(s)
- Christine S Hopp
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA. .,Wellcome Trust Sanger Institute, Hinxton, CB10 1SA, UK.
| | - Amanda E Balaban
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | | | | | | | - Photini Sinnis
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA.
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26
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Sato Y, Hliscs M, Dunst J, Goosmann C, Brinkmann V, Montagna GN, Matuschewski K. Comparative Plasmodium gene overexpression reveals distinct perturbation of sporozoite transmission by profilin. Mol Biol Cell 2016; 27:2234-44. [PMID: 27226484 PMCID: PMC4945141 DOI: 10.1091/mbc.e15-10-0734] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 05/16/2016] [Indexed: 12/27/2022] Open
Abstract
The roles of vital genes, such as those of G-actin–binding proteins, in malaria parasites are underexplored. Overexpression of Plasmodium profilin perturbs actin dynamics only in sporozoites. Strict actin regulation is particularly important for malaria transmission. Mapping of phenotypes can be done by comparative Plasmodium gene overexpression. Plasmodium relies on actin-based motility to migrate from the site of infection and invade target cells. Using a substrate-dependent gliding locomotion, sporozoites are able to move at fast speed (1–3 μm/s). This motility relies on a minimal set of actin regulatory proteins and occurs in the absence of detectable filamentous actin (F-actin). Here we report an overexpression strategy to investigate whether perturbations of F-actin steady-state levels affect gliding locomotion and host invasion. We selected two vital Plasmodium berghei G-actin–binding proteins, C-CAP and profilin, in combination with three stage-specific promoters and mapped the phenotypes afforded by overexpression in all three extracellular motile stages. We show that in merozoites and ookinetes, additional expression does not impair life cycle progression. In marked contrast, overexpression of C-CAP and profilin in sporozoites impairs circular gliding motility and salivary gland invasion. The propensity for productive motility correlates with actin accumulation at the parasite tip, as revealed by combinations of an actin-stabilizing drug and transgenic parasites. Strong expression of profilin, but not C-CAP, resulted in complete life cycle arrest. Comparative overexpression is an alternative experimental genetic strategy to study essential genes and reveals effects of regulatory imbalances that are not uncovered from deletion-mutant phenotyping.
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Affiliation(s)
- Yuko Sato
- Parasitology Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany Infectious Diseases Interdisciplinary Research Group, Singapore-Massachusetts Institute of Technology Alliance for Research and Technology, 138602 Singapore
| | - Marion Hliscs
- Parasitology Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany School of BioSciences, University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Josefine Dunst
- Parasitology Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany Institute for Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Christian Goosmann
- Imaging Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
| | - Volker Brinkmann
- Imaging Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
| | - Georgina N Montagna
- Parasitology Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany Departamento de Microbiologia, Immunologia e Parasitologia, Universidade Federal de São Paulo, 04039-032 São Paulo, Brazil
| | - Kai Matuschewski
- Parasitology Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany Institute of Biology, Humboldt University, 10117 Berlin, Germany
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Singh N, Barnes SJ, Jenwithisuk R, Sattabongkot J, Adams JH. A simple and efficient method for cryopreservation and recovery of viable Plasmodium vivax and P. falciparum sporozoites. Parasitol Int 2015; 65:552-557. [PMID: 26680158 DOI: 10.1016/j.parint.2015.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/12/2015] [Accepted: 12/06/2015] [Indexed: 11/16/2022]
Abstract
Plasmodium falciparum and Plasmodium vivax sporozoites are the crucial stages of malaria parasites that initiate infection in humans. However, studies to develop new vaccines and drugs targeting these infective stages remain insufficient due to limited availability of sporozoites for research. This is a consequence of relatively few facilities that are established to produce sporozoites of human malaria parasites, sporozoites remaining viable for only a few days, and infected mosquitoes being a biohazard, making them difficult to transport. Cryopreservation of sporozoites offers the potential to alleviate these limitations and enhance sporozoite availability. These experiments were performed to evaluate methods for cryopreservation of P. vivax and P. falciparum sporozoites. Sporozoites, isolated in sterile buffer from infected mosquitoes by manual dissection of salivary glands, were cryopreserved using several types of commercially available serum-free cryoprotective solutions. The efficiency of cryopreservation was validated by a standard in vitro gliding motility assay as a measure of sporozoite activity. Viability of infective sporozoites was defined as percent gliding of sporozoites attached to the coverslip. Significant differences were observed among the cryopreservation media and protocols evaluated, with CryoStor CS2 giving the best results for both P. falciparum and P. vivax, whereas Hestar 200 worked efficiently only for P. vivax sporozoites. Further improvement in recovery of viable sporozoites would be anticipated using automated controlled-rate freezing equipment. Our results demonstrate that cryopreservation provides an alternative for experimental studies that currently rely on fresh P. falciparum and P. vivax sporozoites.
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Affiliation(s)
- Naresh Singh
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA
| | - Samantha J Barnes
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA
| | - Rachaneeporn Jenwithisuk
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - John H Adams
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA.
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Wells MB, Andrew DJ. "Salivary gland cellular architecture in the Asian malaria vector mosquito Anopheles stephensi". Parasit Vectors 2015; 8:617. [PMID: 26627194 PMCID: PMC4667400 DOI: 10.1186/s13071-015-1229-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 11/23/2015] [Indexed: 12/02/2022] Open
Abstract
Background Anopheles mosquitoes are vectors for malaria, a disease with continued grave outcomes for human health. Transmission of malaria from mosquitoes to humans occurs by parasite passage through the salivary glands (SGs). Previous studies of mosquito SG architecture have been limited in scope and detail. Methods We developed a simple, optimized protocol for fluorescence staining using dyes and/or antibodies to interrogate cellular architecture in Anopheles stephensi adult SGs. We used common biological dyes, antibodies to well-conserved structural and organellar markers, and antibodies against Anopheles salivary proteins to visualize many individual SGs at high resolution by confocal microscopy. Results These analyses confirmed morphological features previously described using electron microscopy and uncovered a high degree of individual variation in SG structure. Our studies provide evidence for two alternative models for the origin of the salivary duct, the structure facilitating parasite transport out of SGs. We compare SG cellular architecture in An. stephensi and Drosophila melanogaster, a fellow Dipteran whose adult SGs are nearly completely unstudied, and find many conserved features despite divergence in overall form and function. Anopheles salivary proteins previously observed at the basement membrane were localized either in SG cells, secretory cavities, or the SG lumen. Our studies also revealed a population of cells with characteristics consistent with regenerative cells, similar to muscle satellite cells or midgut regenerative cells. Conclusions This work serves as a foundation for linking Anopheles stephensi SG cellular architecture to function and as a basis for generating and evaluating tools aimed at preventing malaria transmission at the level of mosquito SGs. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1229-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michael B Wells
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., G-10 Hunterian, Baltimore, MD, 21205, USA.
| | - Deborah J Andrew
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., G-10 Hunterian, Baltimore, MD, 21205, USA.
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Pinheiro-Silva R, Borges L, Coelho LP, Cabezas-Cruz A, Valdés JJ, do Rosário V, de la Fuente J, Domingos A. Gene expression changes in the salivary glands of Anopheles coluzzii elicited by Plasmodium berghei infection. Parasit Vectors 2015; 8:485. [PMID: 26395987 PMCID: PMC4580310 DOI: 10.1186/s13071-015-1079-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 09/09/2015] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a devastating infectious disease caused by Plasmodium parasites transmitted through the bites of infected Anopheles mosquitoes. Salivary glands are the only mosquito tissue invaded by Plasmodium sporozoites, being a key stage for the effective parasite transmission, making the study of Anopheles sialome highly relevant. Methods RNA-sequencing was used to compare differential gene expression in salivary glands of uninfected and Plasmodium berghei-infected Anopheles coluzzii mosquitoes. RNA-seq results were validated by quantitative RT-PCR. The transmembrane glucose transporter gene AGAP007752 was selected for functional analysis by RNA interference. The effect of gene silencing on infection level was evaluated. The putative function and tertiary structure of the protein was assessed. Results RNA-seq data showed that 2588 genes were differentially expressed in mosquitoes salivary glands in response to P. berghei infection, being 1578 upregulated and 1010 downregulated. Metabolism, Immunity, Replication/Transcription/Translation, Proteolysis and Transport were the mosquito gene functional classes more affected by parasite infection. Endopeptidase coding genes were the most abundant within the differentially expressed genes in infected salivary glands (P < 0.001). Based on its putative function and expression level, the transmembrane glucose transporter gene, AGAP007752, was selected for functional analysis by RNA interference. The results demonstrated that the number of sporozoites was 44.3 % lower in mosquitoes fed on infected mice after AGAPP007752 gene knockdown when compared to control (P < 0.01). Conclusions Our hypothesis is that the protein encoded by the gene AGAPP007752 may play a role on An. coluzzii salivary glands infection by Plasmodium parasite, working as a sporozoite receptor and/or promoting a favorable environment for the capacity of sporozoites. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1079-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Lara Borges
- Instituto de Higiene e Medicina Tropical (IHMT), Lisbon, Portugal. .,Global Health and Tropical Medicine (GHMT), Instituto de Higiene e Medicina Tropical (IHMT), Lisbon, Portugal.
| | - Luís Pedro Coelho
- Unidade de Biofísica e Expressão Genética, Instituto de Medicina Molecular (IMM), Lisbon, Portugal.
| | - Alejandro Cabezas-Cruz
- Center for Infection and Immunity of Lille (CIIL), Institut Pasteur de Lille, Lille, France. .,SaBio. Instituto de Investigación de Recursos Cinegéticos, IREC-CSIC-UCLM-JCCM, Ciudad Real, Spain.
| | - James J Valdés
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, České Budějovice, Czech Republic.
| | | | - José de la Fuente
- SaBio. Instituto de Investigación de Recursos Cinegéticos, IREC-CSIC-UCLM-JCCM, Ciudad Real, Spain. .,Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, USA.
| | - Ana Domingos
- Instituto de Higiene e Medicina Tropical (IHMT), Lisbon, Portugal. .,Global Health and Tropical Medicine (GHMT), Instituto de Higiene e Medicina Tropical (IHMT), Lisbon, Portugal.
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Douglas RG, Amino R, Sinnis P, Frischknecht F. Active migration and passive transport of malaria parasites. Trends Parasitol 2015; 31:357-62. [PMID: 26001482 DOI: 10.1016/j.pt.2015.04.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/22/2015] [Accepted: 04/23/2015] [Indexed: 11/16/2022]
Abstract
Malaria parasites undergo a complex life cycle between their hosts and vectors. During this cycle the parasites invade different types of cells, migrate across barriers, and transfer from one host to another. Recent literature hints at a misunderstanding of the difference between active, parasite-driven migration and passive, circulation-driven movement of the parasite or parasite-infected cells in the various bodily fluids of mosquito and mammalian hosts. Because both active migration and passive transport could be targeted in different ways to interfere with the parasite, a distinction between the two ways the parasite uses to get from one location to another is essential. We discuss the two types of motion needed for parasite dissemination and elaborate on how they could be targeted by future vaccines or drugs.
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Affiliation(s)
- Ross G Douglas
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Rogerio Amino
- Unité de Biologie et Génétique du Paludisme, Département Parasites et Insectes Vecteurs, Institut Pasteur, 25-28 Rue du Dr Roux, 75015 Paris, France
| | - Photini Sinnis
- Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Freddy Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
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31
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Lupton EJ, Roth A, Patrapuvich R, Maher SP, Singh N, Sattabongkot J, Adams JH. Enhancing longevity of Plasmodium vivax and P. falciparum sporozoites after dissection from mosquito salivary glands. Parasitol Int 2014; 64:211-8. [PMID: 25481362 DOI: 10.1016/j.parint.2014.11.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 11/11/2014] [Accepted: 11/18/2014] [Indexed: 11/29/2022]
Abstract
The pre-erythrocytic stages of Plasmodium vivax and Plasmodium falciparum remain challenging for experimental research in part due to limited access to sporozoites. An important factor limiting availability is the laboratory support required for producing infected mosquitoes and the ephemeral nature of isolated extracellular sporozoites. This study was undertaken to investigate methods to improve the availability of this limited resource by extending the longevity of the extracellular sporozoites after mosquito dissection. Our goal in this study was to determine whether buffer conditions more closely mimicking the insect microenvironment could prolong longevity of ex vivo P. vivax and P. falciparum sporozoites. The study compared the current standard dissection buffer RPMI1640 to Hank's Balanced Salt Solution with 1g/L glucose (HBSS-1) or 2g/L glucose (HBSS-2) and Grace's Insect Medium for ability to extend longevity of ex vivo P. vivax and P. falciparum sporozoites. The effect of each buffer on sporozoite viability was evaluated by measuring sporozoite gliding motility at 0, 4, 8, and 24h post-dissection from mosquito salivary glands. Comparisons of mean gliding percentages of ex vivo sporozoites in the different buffers and time points found that RPMI and Grace's both showed strong gliding at 0h. In contrast, by 4h post-dissection sporozoites in RPMI consistently had the lowest gliding activity, whereas sporozoites in Grace's had significantly more gliding compared to all other buffers at almost all time points. Our results indicate that P. vivax and P. falciparum sporozoites maintained in insect media rather than the standard dissection buffer RPMI and HBSS retain viability better over time.
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Affiliation(s)
- Emily J Lupton
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA
| | - Alison Roth
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA
| | | | - Steve P Maher
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA
| | - Naresh Singh
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA
| | | | - John H Adams
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA.
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