1
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Zamani H, Poorinmohammad N, Azimi A, Salavati R. From a bimodal to a multi-stage view on trypanosomes' differential RNA editing. Trends Parasitol 2024; 40:372-377. [PMID: 38494388 DOI: 10.1016/j.pt.2024.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 02/13/2024] [Accepted: 02/22/2024] [Indexed: 03/19/2024]
Abstract
Significant variations in the abundance of mitochondrial RNA processing proteins and their target RNAs across trypanosome life stages present an opportunity to explore the regulatory mechanisms that drive these changes. Utilizing omics approaches can uncover unconventional targets, aiding our understanding of the parasites' adaptation and enabling targeted interventions for differentiation.
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Affiliation(s)
- Homa Zamani
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada
| | - Naghmeh Poorinmohammad
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada
| | - Amin Azimi
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada
| | - Reza Salavati
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada; Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada.
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2
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May DA, Taha F, Child MA, Ewald SE. How colonization bottlenecks, tissue niches, and transmission strategies shape protozoan infections. Trends Parasitol 2023; 39:1074-1086. [PMID: 37839913 DOI: 10.1016/j.pt.2023.09.017] [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: 08/28/2023] [Revised: 09/25/2023] [Accepted: 09/25/2023] [Indexed: 10/17/2023]
Abstract
Protozoan pathogens such as Plasmodium spp., Leishmania spp., Toxoplasma gondii, and Trypanosoma spp. are often associated with high-mortality, acute and chronic diseases of global health concern. For transmission and immune evasion, protozoans have evolved diverse strategies to interact with a range of host tissue environments. These interactions are linked to disease pathology, yet our understanding of the association between parasite colonization and host homeostatic disruption is limited. Recently developed techniques for cellular barcoding have the potential to uncover the biology regulating parasite transmission, dissemination, and the stability of infection. Understanding bottlenecks to infection and the in vivo tissue niches that facilitate chronic infection and spread has the potential to reveal new aspects of parasite biology.
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Affiliation(s)
- Dana A May
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Fatima Taha
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Matthew A Child
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | - Sarah E Ewald
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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3
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Cayla M, Nievas YR, Matthews KR, Mottram JC. Distinguishing functions of trypanosomatid protein kinases. Trends Parasitol 2022; 38:950-961. [PMID: 36075845 DOI: 10.1016/j.pt.2022.08.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 01/13/2023]
Abstract
Trypanosomatid parasitic protozoa are divergent from opisthokont models and have evolved unique mechanisms to regulate their complex life cycles and to adapt to a range of hosts. Understanding how these organisms respond, adapt, and persist in their different hosts could reveal optimal drug-control strategies. Protein kinases are fundamental to many biological processes such as cell cycle control, adaptation to stress, and cellular differentiation. Therefore, we have focused this review on the features and functions of protein kinases that distinguish trypanosomatid kinomes from other eukaryotes. We describe the latest research, highlighting similarities and differences between two groups of trypanosomatid parasites, Leishmania and African trypanosomes.
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Affiliation(s)
- Mathieu Cayla
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Y Romina Nievas
- York Biomedical Research Institute, Department of Biology, University of York, York, UK
| | - Keith R Matthews
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Jeremy C Mottram
- York Biomedical Research Institute, Department of Biology, University of York, York, UK.
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4
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Promastigote-to-Amastigote Conversion in Leishmania spp.—A Molecular View. Pathogens 2022; 11:pathogens11091052. [PMID: 36145483 PMCID: PMC9503511 DOI: 10.3390/pathogens11091052] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 09/08/2022] [Accepted: 09/13/2022] [Indexed: 11/28/2022] Open
Abstract
A key factor in the successful infection of a mammalian host by Leishmania parasites is their conversion from extracellular motile promastigotes into intracellular amastigotes. We discuss the physical and chemical triggers that induce this conversion and the accompanying changes at the molecular level crucial for the survival of these intracellular parasites. Special emphasis is given to the reliance of these trypanosomatids on the post-transcriptional regulation of gene expression but also to the role played by protein kinases, chaperone proteins and proteolytic enzymes. Lastly, we offer a model to integrate the transduction of different stress signals for the induction of stage conversion.
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5
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Sáez Conde J, Dean S. Structure, function and druggability of the African trypanosome flagellum. J Cell Physiol 2022; 237:2654-2667. [PMID: 35616248 PMCID: PMC9323424 DOI: 10.1002/jcp.30778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 04/20/2022] [Accepted: 04/25/2022] [Indexed: 11/29/2022]
Abstract
African trypanosomes are early branching protists that cause human and animal diseases, termed trypanosomiases. They have been under intensive study for more than 100 years and have contributed significantly to our understanding of eukaryotic biology. The combination of conserved and parasite‐specific features mean that their flagellum has gained particular attention. Here, we discuss the different structural features of the flagellum and their role in transmission and virulence. We highlight the possibilities of targeting flagellar function to cure trypanosome infections and help in the fight to eliminate trypanosomiases.
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Affiliation(s)
- Julia Sáez Conde
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Samuel Dean
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
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6
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Sánchez-Arcila JC, Jensen KDC. Forward Genetics in Apicomplexa Biology: The Host Side of the Story. Front Cell Infect Microbiol 2022; 12:878475. [PMID: 35646724 PMCID: PMC9133346 DOI: 10.3389/fcimb.2022.878475] [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: 02/18/2022] [Accepted: 03/31/2022] [Indexed: 11/13/2022] Open
Abstract
Forward genetic approaches have been widely used in parasitology and have proven their power to reveal the complexities of host-parasite interactions in an unbiased fashion. Many aspects of the parasite’s biology, including the identification of virulence factors, replication determinants, antibiotic resistance genes, and other factors required for parasitic life, have been discovered using such strategies. Forward genetic approaches have also been employed to understand host resistance mechanisms to parasitic infection. Here, we will introduce and review all forward genetic approaches that have been used to identify host factors involved with Apicomplexa infections, which include classical genetic screens and QTL mapping, GWAS, ENU mutagenesis, overexpression, RNAi and CRISPR-Cas9 library screens. Collectively, these screens have improved our understanding of host resistance mechanisms, immune regulation, vaccine and drug designs for Apicomplexa parasites. We will also discuss how recent advances in molecular genetics give present opportunities to further explore host-parasite relationships.
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Affiliation(s)
- Juan C. Sánchez-Arcila
- Department of Molecular and Cell Biology, University of California Merced, Merced, CA, United States
| | - Kirk D. C. Jensen
- Department of Molecular and Cell Biology, University of California Merced, Merced, CA, United States
- Health Science Research Institute, University of California, Merced, Merced, CA, United States
- *Correspondence: Kirk D. C. Jensen,
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7
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Kaur P, Goyal N. Pathogenic role of mitogen activated protein kinases in protozoan parasites. Biochimie 2021; 193:78-89. [PMID: 34706251 DOI: 10.1016/j.biochi.2021.10.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 09/29/2021] [Accepted: 10/21/2021] [Indexed: 01/18/2023]
Abstract
Protozoan parasites with complex life cycles have high mortality rates affecting billions of human lives. Available anti-parasitic drugs are inadequate due to variable efficacy, toxicity, poor patient compliance and drug-resistance. Hence, there is an urgent need for the development of safer and better chemotherapeutics. Mitogen Activated Protein Kinases (MAPKs) have drawn much attention as potential drug targets. This review summarizes unique structural and functional features of MAP kinases and their possible role in pathogenesis of obligate intracellular protozoan parasites namely, Leishmania, Trypanosoma, Plasmodium and Toxoplasma. It also provides an overview of available knowledge concerning the target proteins of parasite MAPKs and the need to understand and unravel unknown interaction network(s) of MAPK(s).
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Affiliation(s)
- Pavneet Kaur
- Division of Biochemistry and Structural Biology, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, Uttar Pradesh, India
| | - Neena Goyal
- Division of Biochemistry and Structural Biology, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, Uttar Pradesh, India.
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8
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Jensen BC, Vaney P, Flaspohler J, Coppens I, Parsons M. Unusual features and localization of the membrane kinome of Trypanosoma brucei. PLoS One 2021; 16:e0258814. [PMID: 34653230 PMCID: PMC8519429 DOI: 10.1371/journal.pone.0258814] [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: 07/22/2021] [Accepted: 10/05/2021] [Indexed: 11/23/2022] Open
Abstract
In many eukaryotes, multiple protein kinases are situated in the plasma membrane where they respond to extracellular ligands. Ligand binding elicits a signal that is transmitted across the membrane, leading to activation of the cytosolic kinase domain. Humans have over 100 receptor protein kinases. In contrast, our search of the Trypanosoma brucei kinome showed that there were only ten protein kinases with predicted transmembrane domains, and unlike other eukaryotic transmembrane kinases, seven are predicted to bear multiple transmembrane domains. Most of the ten kinases, including their transmembrane domains, are conserved in both Trypanosoma cruzi and Leishmania species. Several possess accessory domains, such as Kelch, nucleotide cyclase, and forkhead-associated domains. Surprisingly, two contain multiple regions with predicted structural similarity to domains in bacterial signaling proteins. A few of the protein kinases have previously been localized to subcellular structures such as endosomes or lipid bodies. We examined the localization of epitope-tagged versions of seven of the predicted transmembrane kinases in T. brucei bloodstream forms and show that five localized to the endoplasmic reticulum. The last two kinases are enzymatically active, integral membrane proteins associated with the flagellum, flagellar pocket, or adjacent structures as shown by both fluorescence and immunoelectron microscopy. Thus, these kinases are positioned in structures suggesting participation in signal transduction from the external environment.
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Affiliation(s)
- Bryan C. Jensen
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- * E-mail:
| | - Pashmi Vaney
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - John Flaspohler
- Biology Department, Concordia College, Moorhead, Minnesota, United States of America
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Marilyn Parsons
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Departments of Pediatrics and Global Health, University of Washington, Seattle, Washington, United States of America
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9
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Horn D. Genome-scale RNAi screens in African trypanosomes. Trends Parasitol 2021; 38:160-173. [PMID: 34580035 DOI: 10.1016/j.pt.2021.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/31/2021] [Accepted: 09/01/2021] [Indexed: 12/11/2022]
Abstract
Genome-scale genetic screens allow researchers to rapidly identify the genes and proteins that impact a particular phenotype of interest. In African trypanosomes, RNA interference (RNAi) knockdown screens have revealed mechanisms underpinning drug resistance, drug transport, prodrug metabolism, quorum sensing, genome replication, and gene expression control. RNAi screening has also been remarkably effective at highlighting promising potential antitrypanosomal drug targets. The first ever RNAi library screen was implemented in African trypanosomes, and genome-scale RNAi screens and other related approaches continue to have a major impact on trypanosomatid research. Here, I review those impacts in terms of both discovery and translation.
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Affiliation(s)
- David Horn
- The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
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10
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Silva GLA, Tosi LRO, McCulloch R, Black JA. Unpicking the Roles of DNA Damage Protein Kinases in Trypanosomatids. Front Cell Dev Biol 2021; 9:636615. [PMID: 34422791 PMCID: PMC8377203 DOI: 10.3389/fcell.2021.636615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 07/13/2021] [Indexed: 12/31/2022] Open
Abstract
To preserve genome integrity when faced with DNA lesions, cells activate and coordinate a multitude of DNA repair pathways to ensure timely error correction or tolerance, collectively called the DNA damage response (DDR). These interconnecting damage response pathways are molecular signal relays, with protein kinases (PKs) at the pinnacle. Focused efforts in model eukaryotes have revealed intricate aspects of DNA repair PK function, including how they direct DDR pathways and how repair reactions connect to wider cellular processes, including DNA replication and transcription. The Kinetoplastidae, including many parasites like Trypanosoma spp. and Leishmania spp. (causative agents of debilitating, neglected tropical infections), exhibit peculiarities in several core biological processes, including the predominance of multigenic transcription and the streamlining or repurposing of DNA repair pathways, such as the loss of non-homologous end joining and novel operation of nucleotide excision repair (NER). Very recent studies have implicated ATR and ATM kinases in the DDR of kinetoplastid parasites, whereas DNA-dependent protein kinase (DNA-PKcs) displays uncertain conservation, questioning what functions it fulfills. The wide range of genetic manipulation approaches in these organisms presents an opportunity to investigate DNA repair kinase roles in kinetoplastids and to ask if further kinases are involved. Furthermore, the availability of kinase inhibitory compounds, targeting numerous eukaryotic PKs, could allow us to test the suitability of DNA repair PKs as novel chemotherapeutic targets. Here, we will review recent advances in the study of trypanosomatid DNA repair kinases.
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Affiliation(s)
- Gabriel L A Silva
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom.,Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Luiz R O Tosi
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Richard McCulloch
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Jennifer Ann Black
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom.,Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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11
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Dean S. Basic Biology of Trypanosoma brucei with Reference to the Development of Chemotherapies. Curr Pharm Des 2021; 27:1650-1670. [PMID: 33463458 DOI: 10.2174/1381612827666210119105008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/01/2020] [Accepted: 12/08/2020] [Indexed: 11/22/2022]
Abstract
Trypanosoma brucei are protozoan parasites that cause the lethal human disease African sleeping sickness and the economically devastating disease of cattle, Nagana. African sleeping sickness, also known as Human African Trypanosomiasis (HAT), threatens 65 million people and animal trypanosomiasis makes large areas of farmland unusable. There is no vaccine and licensed therapies against the most severe, late-stage disease are toxic, impractical and ineffective. Trypanosomes are transmitted by tsetse flies, and HAT is therefore predominantly confined to the tsetse fly belt in sub-Saharan Africa. They are exclusively extracellular and they differentiate between at least seven developmental forms that are highly adapted to host and vector niches. In the mammalian (human) host they inhabit the blood, cerebrospinal fluid (late-stage disease), skin, and adipose fat. In the tsetse fly vector they travel from the tsetse midgut to the salivary glands via the ectoperitrophic space and proventriculus. Trypanosomes are evolutionarily divergent compared with most branches of eukaryotic life. Perhaps most famous for their extraordinary mechanisms of monoallelic gene expression and antigenic variation, they have also been investigated because much of their biology is either highly unconventional or extreme. Moreover, in addition to their importance as pathogens, many researchers have been attracted to the field because trypanosomes have some of the most advanced molecular genetic tools and database resources of any model system. The following will cover just some aspects of trypanosome biology and how its divergent biochemistry has been leveraged to develop drugs to treat African sleeping sickness. This is by no means intended to be a comprehensive survey of trypanosome features. Rather, I hope to present trypanosomes as one of the most fascinating and tractable systems to do discovery biology.
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Affiliation(s)
- Samuel Dean
- Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
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12
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Levy DJ, Goundry A, Laires RSS, Costa TFR, Novo CM, Grab DJ, Mottram JC, Lima APCA. Role of the inhibitor of serine peptidase 2 (ISP2) of Trypanosoma brucei rhodesiense in parasite virulence and modulation of the inflammatory responses of the host. PLoS Negl Trop Dis 2021; 15:e0009526. [PMID: 34153047 PMCID: PMC8248637 DOI: 10.1371/journal.pntd.0009526] [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: 11/08/2020] [Revised: 07/01/2021] [Accepted: 06/01/2021] [Indexed: 11/18/2022] Open
Abstract
Trypanosoma brucei rhodesiense is one of the causative agents of Human African Trypanosomiasis (HAT), known as sleeping sickness. The parasite invades the central nervous system and causes severe encephalitis that is fatal if left untreated. We have previously identified ecotin-like inhibitors of serine peptidases, named ISPs, in trypanosomatid parasitic protozoa. Here, we investigated the role of ISP2 in bloodstream form T. b. rhodesiense. We generated gene-deficient mutants lacking ISP2 (Δisp2), which displayed a growth profile in vitro similar to that of wild-type (WT) parasites. C57BL/6 mice infected with Δisp2 displayed lower blood parasitemia, a delayed hind leg pathological phenotype and survived longer. The immune response was examined at two time-points that corresponded with two peaks of parasitemia. At 4 days, the spleens of Δisp2-infected mice had a greater percentage of NOS2+ myeloid cells, IFN-γ+-NK cells and increased TNF-α compared to those infected with WT and parasites re-expressing ISP2 (Δisp2:ISP2). By 13 days the increased NOS2+ population was sustained in Δisp2-infected mice, along with increased percentages of monocyte-derived dendritic cells, as well as CD19+ B lymphocytes, and CD8+ and CD4+ T lymphocytes. Taken together, these findings indicate that ISP2 contributes to T. b. rhodesiense virulence in mice and attenuates the inflammatory response during early infection.
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Affiliation(s)
- David Jessula Levy
- Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Centro de Ciências da Saúde, Ilha do Fundão, Rio de Janeiro, RJ, Brazil
| | - Amy Goundry
- Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Centro de Ciências da Saúde, Ilha do Fundão, Rio de Janeiro, RJ, Brazil
| | - Raquel S. S. Laires
- Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Tatiana F. R. Costa
- Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Centro de Ciências da Saúde, Ilha do Fundão, Rio de Janeiro, RJ, Brazil
| | - Carlos Mendes Novo
- Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Dennis J. Grab
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland; Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jeremy C. Mottram
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
- York Biomedical Research Institute and Department of Biology, University of York, York, United Kingdom
| | - Ana Paula C. A. Lima
- Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Centro de Ciências da Saúde, Ilha do Fundão, Rio de Janeiro, RJ, Brazil
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13
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Black JA, Crouch K, Lemgruber L, Lapsley C, Dickens N, Tosi LRO, Mottram JC, McCulloch R. Trypanosoma brucei ATR Links DNA Damage Signaling during Antigenic Variation with Regulation of RNA Polymerase I-Transcribed Surface Antigens. Cell Rep 2021; 30:836-851.e5. [PMID: 31968257 PMCID: PMC6988115 DOI: 10.1016/j.celrep.2019.12.049] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 08/19/2019] [Accepted: 12/13/2019] [Indexed: 11/29/2022] Open
Abstract
Trypanosoma brucei evades mammalian immunity by using recombination to switch its surface-expressed variant surface glycoprotein (VSG), while ensuring that only one of many subtelomeric multigene VSG expression sites are transcribed at a time. DNA repair activities have been implicated in the catalysis of VSG switching by recombination, not transcriptional control. How VSG switching is signaled to guide the appropriate reaction or to integrate switching into parasite growth is unknown. Here, we show that the loss of ATR, a DNA damage-signaling protein kinase, is lethal, causing nuclear genome instability and increased VSG switching through VSG-localized damage. Furthermore, ATR loss leads to the increased transcription of silent VSG expression sites and expression of mixed VSGs on the cell surface, effects that are associated with the altered localization of RNA polymerase I and VEX1. This work shows that ATR acts in antigenic variation both through DNA damage signaling and surface antigen expression control. Loss of the repair protein kinase ATR in Trypanosoma brucei is lethal Loss of T. brucei ATR alters VSG coat expression needed for immune evasion Monoallelic RNA polymerase I VSG expression is undermined by ATR loss ATR loss leads to expression of subtelomeric VSGs, indicative of recombination
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Affiliation(s)
- Jennifer Ann Black
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow G12 8TA, UK; Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900 SP, Brazil
| | - Kathryn Crouch
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow G12 8TA, UK
| | - Leandro Lemgruber
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow G12 8TA, UK
| | - Craig Lapsley
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow G12 8TA, UK
| | - Nicholas Dickens
- Marine Science Lab, FAU Harbor Branch Oceanographic Institute, 5600 US 1 North, Fort Pierce, FL 34946, USA
| | - Luiz R O Tosi
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900 SP, Brazil
| | - Jeremy C Mottram
- Centre for Immunology and Infection, Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Richard McCulloch
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow G12 8TA, UK.
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14
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Baker N, Catta-Preta CMC, Neish R, Sadlova J, Powell B, Alves-Ferreira EVC, Geoghegan V, Carnielli JBT, Newling K, Hughes C, Vojtkova B, Anand J, Mihut A, Walrad PB, Wilson LG, Pitchford JW, Volf P, Mottram JC. Systematic functional analysis of Leishmania protein kinases identifies regulators of differentiation or survival. Nat Commun 2021; 12:1244. [PMID: 33623024 PMCID: PMC7902614 DOI: 10.1038/s41467-021-21360-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 01/13/2021] [Indexed: 01/31/2023] Open
Abstract
Differentiation between distinct stages is fundamental for the life cycle of intracellular protozoan parasites and for transmission between hosts, requiring stringent spatial and temporal regulation. Here, we apply kinome-wide gene deletion and gene tagging in Leishmania mexicana promastigotes to define protein kinases with life cycle transition roles. Whilst 162 are dispensable, 44 protein kinase genes are refractory to deletion in promastigotes and are likely core genes required for parasite replication. Phenotyping of pooled gene deletion mutants using bar-seq and projection pursuit clustering reveal functional phenotypic groups of protein kinases involved in differentiation from metacyclic promastigote to amastigote, growth and survival in macrophages and mice, colonisation of the sand fly and motility. This unbiased interrogation of protein kinase function in Leishmania allows targeted investigation of organelle-associated signalling pathways required for successful intracellular parasitism.
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Affiliation(s)
- N Baker
- York Biomedical Research Institute, University of York, York, UK
- Department of Biology, University of York, York, UK
| | - C M C Catta-Preta
- York Biomedical Research Institute, University of York, York, UK
- Department of Biology, University of York, York, UK
| | - R Neish
- York Biomedical Research Institute, University of York, York, UK
- Department of Biology, University of York, York, UK
| | - J Sadlova
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - B Powell
- Department of Mathematics, University of York, York, UK
| | - E V C Alves-Ferreira
- York Biomedical Research Institute, University of York, York, UK
- Department of Biology, University of York, York, UK
| | - V Geoghegan
- York Biomedical Research Institute, University of York, York, UK
- Department of Biology, University of York, York, UK
| | - J B T Carnielli
- York Biomedical Research Institute, University of York, York, UK
- Department of Biology, University of York, York, UK
| | - K Newling
- Department of Biology, University of York, York, UK
| | - C Hughes
- York Biomedical Research Institute, University of York, York, UK
- Department of Biology, University of York, York, UK
| | - B Vojtkova
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - J Anand
- York Biomedical Research Institute, University of York, York, UK
- Department of Biology, University of York, York, UK
| | - A Mihut
- Department of Biology, University of York, York, UK
| | - P B Walrad
- York Biomedical Research Institute, University of York, York, UK
- Department of Biology, University of York, York, UK
| | - L G Wilson
- York Biomedical Research Institute, University of York, York, UK
- Department of Physics, University of York, York, UK
| | - J W Pitchford
- Department of Biology, University of York, York, UK
- Department of Mathematics, University of York, York, UK
| | - P Volf
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - J C Mottram
- York Biomedical Research Institute, University of York, York, UK.
- Department of Biology, University of York, York, UK.
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15
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Rocha VPC, Dacher M, Young SA, Kolokousi F, Efstathiou A, Späth GF, Soares MBP, Smirlis D. Leishmania dual-specificity tyrosine-regulated kinase 1 (DYRK1) is required for sustaining Leishmania stationary phase phenotype. Mol Microbiol 2020; 113:983-1002. [PMID: 31975452 DOI: 10.1111/mmi.14464] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 01/13/2020] [Accepted: 01/16/2020] [Indexed: 01/05/2023]
Abstract
Although the multiplicative and growth-arrested states play key roles in Leishmania development, the regulators of these transitions are largely unknown. In an attempt to gain a better understanding of these processes, we characterised one member of a family of protein kinases with dual specificity, LinDYRK1, which acts as a stasis regulator in other organisms. LinDYRK1 overexpressing parasites displayed a decrease in proliferation and in cell cycle re-entry of arrested cells. Parasites lacking LinDYRK1 displayed distinct fitness phenotypes in logarithmic and stationary growth phases. In logarithmic growth phase, LinDYRK1-/- parasites proliferated better than control lines, supporting a role of this kinase in stasis, while in stationary growth phase, LinDYRK1-/- parasites had important defects as they rounded up, accumulated vacuoles and lipid bodies and displayed subtle but consistent differences in lipid composition. Moreover, they expressed less metacyclic-enriched transcripts, displayed increased sensitivity to complement lysis and a significant reduction in survival within peritoneal macrophages. The distinct LinDYRK1-/- growth phase phenotypes were mirrored by the distinct LinDYRK1 localisations in logarithmic (mainly in flagellar pocket area and endosomes) and late stationary phase (mitochondrion). Overall, this work provides first evidence for the role of a DYRK family member in sustaining promastigote stationary phase phenotype and infectivity.
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Affiliation(s)
- Vinícius Pinto Costa Rocha
- Instituto Gonçalo Moniz, Fundação Oswaldo Cruz (FIOCRUZ), Salvador, Brazil
- Centro de Biotecnologia e Terapia Celular, Hospital São Rafael, Salvador, Brazil
| | - Mariko Dacher
- Unité de Parasitologie Moléculaire et Signalisation, Department of Parasites and Insect Vectors, Institut Pasteur and INSERM U1201, Paris, France
| | - Simon Alan Young
- Biomedical Sciences Research Complex, School of Biology, The University of St. Andrews, St. Andrews, UK
| | - Foteini Kolokousi
- Molecular Parasitology Laboratory, Microbiology Department, Hellenic Pasteur Institute, Athens, Greece
| | - Antonia Efstathiou
- Molecular Parasitology Laboratory, Microbiology Department, Hellenic Pasteur Institute, Athens, Greece
| | - Gerald Frank Späth
- Unité de Parasitologie Moléculaire et Signalisation, Department of Parasites and Insect Vectors, Institut Pasteur and INSERM U1201, Paris, France
| | - Milena Botelho Pereira Soares
- Instituto Gonçalo Moniz, Fundação Oswaldo Cruz (FIOCRUZ), Salvador, Brazil
- Centro de Biotecnologia e Terapia Celular, Hospital São Rafael, Salvador, Brazil
| | - Despina Smirlis
- Molecular Parasitology Laboratory, Microbiology Department, Hellenic Pasteur Institute, Athens, Greece
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16
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Altamura F, Rajesh R, Catta-Preta CMC, Moretti NS, Cestari I. The current drug discovery landscape for trypanosomiasis and leishmaniasis: Challenges and strategies to identify drug targets. Drug Dev Res 2020; 83:225-252. [PMID: 32249457 DOI: 10.1002/ddr.21664] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 02/05/2020] [Accepted: 03/13/2020] [Indexed: 12/11/2022]
Abstract
Human trypanosomiasis and leishmaniasis are vector-borne neglected tropical diseases caused by infection with the protozoan parasites Trypanosoma spp. and Leishmania spp., respectively. Once restricted to endemic areas, these diseases are now distributed worldwide due to human migration, climate change, and anthropogenic disturbance, causing significant health and economic burden globally. The current chemotherapy used to treat these diseases has limited efficacy, and drug resistance is spreading. Hence, new drugs are urgently needed. Phenotypic compound screenings have prevailed as the leading method to discover new drug candidates against these diseases. However, the publication of the complete genome sequences of multiple strains, advances in the application of CRISPR/Cas9 technology, and in vivo bioluminescence-based imaging have set the stage for advancing target-based drug discovery. This review analyses the limitations of the narrow pool of available drugs presently used for treating these diseases. It describes the current drug-based clinical trials highlighting the most promising leads. Furthermore, the review presents a focused discussion on the most important biological and pharmacological challenges that target-based drug discovery programs must overcome to advance drug candidates. Finally, it examines the advantages and limitations of modern research tools designed to identify and validate essential genes as drug targets, including genomic editing applications and in vivo imaging.
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Affiliation(s)
- Fernando Altamura
- Institute of Parasitology, McGill University, Ste Anne de Bellevue, Quebec, Canada
| | - Rishi Rajesh
- Institute of Parasitology, McGill University, Ste Anne de Bellevue, Quebec, Canada
| | | | - Nilmar S Moretti
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Igor Cestari
- Institute of Parasitology, McGill University, Ste Anne de Bellevue, Quebec, Canada
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17
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Varikuti S, Jha BK, Volpedo G, Ryan NM, Halsey G, Hamza OM, McGwire BS, Satoskar AR. Host-Directed Drug Therapies for Neglected Tropical Diseases Caused by Protozoan Parasites. Front Microbiol 2018; 9:2655. [PMID: 30555425 PMCID: PMC6284052 DOI: 10.3389/fmicb.2018.02655] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/17/2018] [Indexed: 12/11/2022] Open
Abstract
The neglected tropical diseases (NTDs) caused by protozoan parasites are responsible for significant morbidity and mortality worldwide. Current treatments using anti-parasitic drugs are toxic and prolonged with poor patient compliance. In addition, emergence of drug-resistant parasites is increasing worldwide. Hence, there is a need for safer and better therapeutics for these infections. Host-directed therapy using drugs that target host pathways required for pathogen survival or its clearance is a promising approach for treating infections. This review will give a summary of the current status and advances of host-targeted therapies for treating NTDs caused by protozoa.
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Affiliation(s)
- Sanjay Varikuti
- Department of Pathology, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Bijay Kumar Jha
- Division of Infectious Diseases, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
| | - Greta Volpedo
- Department of Pathology, Wexner Medical Center, The Ohio State University, Columbus, OH, United States.,Department of Microbiology, The Ohio State University, Columbus, OH, United States
| | - Nathan M Ryan
- Department of Pathology, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Gregory Halsey
- Department of Pathology, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Omar M Hamza
- Department of Pathology, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Bradford S McGwire
- Division of Infectious Diseases, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
| | - Abhay R Satoskar
- Department of Pathology, Wexner Medical Center, The Ohio State University, Columbus, OH, United States.,Department of Microbiology, The Ohio State University, Columbus, OH, United States
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18
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Kelner A, Tinti M, Guther MLS, Foth BJ, Chappell L, Berriman M, Cowling VH, Ferguson MAJ. The mRNA cap methyltransferase gene TbCMT1 is not essential in vitro but is a virulence factor in vivo for bloodstream form Trypanosoma brucei. PLoS One 2018; 13:e0201263. [PMID: 30040830 PMCID: PMC6057678 DOI: 10.1371/journal.pone.0201263] [Citation(s) in RCA: 2] [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: 05/09/2018] [Accepted: 07/11/2018] [Indexed: 01/16/2023] Open
Abstract
Messenger RNA is modified by the addition of a 5' methylated cap structure, which protects the transcript and recruits protein complexes that mediate RNA processing and/or the initiation of translation. Two genes encoding mRNA cap methyltransferases have been identified in T. brucei: TbCMT1 and TbCGM1. Here we analysed the impact of TbCMT1 gene deletion on bloodstream form T. brucei cells. TbCMT1 was dispensable for parasite proliferation in in vitro culture. However, significantly decreased parasitemia was observed in mice inoculated with TbCMT1 null and conditional null cell lines. Using RNA-Seq, we observed that several cysteine peptidase mRNAs were downregulated in TbCMT1 null cells lines. The cysteine peptidase Cathepsin-L was also shown to be reduced at the protein level in TbCMT1 null cell lines. Our data suggest that TbCMT1 is not essential to bloodstream form T. brucei growth in vitro or in vivo but that it contributes significantly to parasite virulence in vivo.
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Affiliation(s)
- Anna Kelner
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Michele Tinti
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Maria Lucia S. Guther
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | | | - Lia Chappell
- The Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | | | - Victoria Haigh Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Michael A. J. Ferguson
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
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19
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Jones NG, Catta-Preta CMC, Lima APCA, Mottram JC. Genetically Validated Drug Targets in Leishmania: Current Knowledge and Future Prospects. ACS Infect Dis 2018; 4:467-477. [PMID: 29384366 PMCID: PMC5902788 DOI: 10.1021/acsinfecdis.7b00244] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
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There has been a very limited number
of high-throughput screening campaigns carried out with Leishmania drug targets. In part, this is due to the small number of suitable
target genes that have been shown by genetic or chemical methods to
be essential for the parasite. In this perspective, we discuss the
state of genetic target validation in the field of Leishmania research and review the 200 Leishmania genes and
36 Trypanosoma cruzi genes for which gene deletion
attempts have been made since the first published case in 1990. We
define a quality score for the different genetic deletion techniques
that can be used to identify potential drug targets. We also discuss
how the advances in genome-scale gene disruption techniques have been
used to assist target-based and phenotypic-based drug development
in other parasitic protozoa and why Leishmania has
lacked a similar approach so far. The prospects for this scale of
work are considered in the context of the application of CRISPR/Cas9
gene editing as a useful tool in Leishmania.
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Affiliation(s)
- Nathaniel G. Jones
- Centre for Immunology and Infection, Department of Biology, University of York, Wentworth Way, Heslington, York YO10 5DD, U.K
| | - Carolina M. C. Catta-Preta
- Centre for Immunology and Infection, Department of Biology, University of York, Wentworth Way, Heslington, York YO10 5DD, U.K
| | - Ana Paula C. A. Lima
- Instituto de Biofisica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, RJ 21941-902, Brazil
| | - Jeremy C. Mottram
- Centre for Immunology and Infection, Department of Biology, University of York, Wentworth Way, Heslington, York YO10 5DD, U.K
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20
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Naguleswaran A, Doiron N, Roditi I. RNA-Seq analysis validates the use of culture-derived Trypanosoma brucei and provides new markers for mammalian and insect life-cycle stages. BMC Genomics 2018; 19:227. [PMID: 29606092 PMCID: PMC5879877 DOI: 10.1186/s12864-018-4600-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 03/13/2018] [Indexed: 01/03/2023] Open
Abstract
Background Trypanosoma brucei brucei, the parasite causing Nagana in domestic animals, is closely related to the parasites causing sleeping sickness, but does not infect humans. In addition to its importance as a pathogen, the relative ease of genetic manipulation and an innate capacity for RNAi extend its use as a model organism in cell and infection biology. During its development in its mammalian and insect (tsetse fly) hosts, T. b. brucei passes through several different life-cycle stages. There are currently four life-cycle stages that can be cultured: slender forms and stumpy forms, which are equivalent to forms found in the mammal, and early and late procyclic forms, which are equivalent to forms in the tsetse midgut. Early procyclic forms show coordinated group movement (social motility) on semi-solid surfaces, whereas late procyclic forms do not. Results RNA-Seq was performed on biological replicates of each life-cycle stage. These constitute the first datasets for culture-derived slender and stumpy bloodstream forms and early and late procyclic forms. Expression profiles confirmed that genes known to be stage-regulated in the animal and insect hosts were also regulated in culture. Sequence reads of 100–125 bases provided sufficient precision to uncover differential expression of closely related genes. More than 100 transcripts showed peak expression in stumpy forms, including adenylate cyclases and several components of inositol metabolism. Early and late procyclic forms showed differential expression of 73 transcripts, a number of which encoded proteins that were previously shown to be stage-regulated. Moreover, two adenylate cyclases previously shown to reduce social motility are up-regulated in late procyclic forms. Conclusions This study validates the use of cultured bloodstream forms as alternatives to animal-derived parasites and yields new markers for all four stages. In addition to underpinning recent findings that early and late procyclic forms are distinct life-cycle stages, it could provide insights into the reasons for their different biological properties. Electronic supplementary material The online version of this article (10.1186/s12864-018-4600-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Nicholas Doiron
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012, Bern, Switzerland
| | - Isabel Roditi
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012, Bern, Switzerland.
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21
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Elaadli H, Kim I, Mackey ZB. Depletion of the extracellular-signal regulated kinase 8 homolog in Trypanosoma brucei in vivo reduces its virulence in a mouse target validation study. Mol Biochem Parasitol 2017; 220:1-4. [PMID: 29287675 DOI: 10.1016/j.molbiopara.2017.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 12/21/2017] [Accepted: 12/22/2017] [Indexed: 12/01/2022]
Abstract
Trypanosoma brucei sub-species are vector borne kinetoplastid parasites that cause the potentially lethal disease Human African trypanosomiasis. The target-based therapy for curing this parasitic disease relies on one drug, Eflornithine. The roles of mitogen-activated protein kinases in regulating key cellular processes in eukaryotic cells such as proliferation, stress response and differentiation plus their druggability make them attractive targets for therapeutic exploitation. The extracellular-regulated kinase 8 homolog in T. brucei (TbERK8) is a MAPK that is required for the parasite to proliferate normally in culture. We examined the importance of TbERK8 for permitting T. brucei to thrive in mice. Here we show that depleting TbERK8 in vivo negatively affected the virulence of T. brucei reducing its ability to progress to lethal infections or cause significant pathology in mice, which validates it as an attractive target.
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Affiliation(s)
- Haitham Elaadli
- Department of Biochemistry and Fralin Life Science Institute, Vector-Borne Disease Division, Virginia Tech, Blacksburg, VA 24061, United States; Department of Animal Hygiene and Zoonoses, Faculty of Veterinary Medicine, Alexandria University, Egypt
| | - Inyoung Kim
- Department of Statistics, Virginia Polytechnic Institute and State University, United States
| | - Zachary B Mackey
- Department of Biochemistry and Fralin Life Science Institute, Vector-Borne Disease Division, Virginia Tech, Blacksburg, VA 24061, United States.
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22
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Genome-wide and protein kinase-focused RNAi screens reveal conserved and novel damage response pathways in Trypanosoma brucei. PLoS Pathog 2017; 13:e1006477. [PMID: 28742144 PMCID: PMC5542689 DOI: 10.1371/journal.ppat.1006477] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 08/03/2017] [Accepted: 06/17/2017] [Indexed: 12/21/2022] Open
Abstract
All cells are subject to structural damage that must be addressed for continued growth. A wide range of damage affects the genome, meaning multiple pathways have evolved to repair or bypass the resulting DNA lesions. Though many repair pathways are conserved, their presence or function can reflect the life style of individual organisms. To identify genome maintenance pathways in a divergent eukaryote and important parasite, Trypanosoma brucei, we performed RNAi screens to identify genes important for survival following exposure to the alkylating agent methyl methanesulphonate. Amongst a cohort of broadly conserved and, therefore, early evolved repair pathways, we reveal multiple activities not so far examined functionally in T. brucei, including DNA polymerases, DNA helicases and chromatin factors. In addition, the screens reveal Trypanosoma- or kinetoplastid-specific repair-associated activities. We also provide focused analyses of repair-associated protein kinases and show that loss of at least nine, and potentially as many as 30 protein kinases, including a nuclear aurora kinase, sensitises T. brucei to alkylation damage. Our results demonstrate the potential for synthetic lethal genome-wide screening of gene function in T. brucei and provide an evolutionary perspective on the repair pathways that underpin effective responses to damage, with particular relevance for related kinetoplastid pathogens. By revealing that a large number of diverse T. brucei protein kinases act in the response to damage, we expand the range of eukaryotic signalling factors implicated in genome maintenance activities. Damage to the genome is a universal threat to life. Though the repair pathways used to tackle damage can be widely conserved, lineage-specific specialisations are found, reflecting the differing life styles of extant organisms. Using RNAi coupled with next generation sequencing we have screened for genes that are important for growth of Trypanosoma brucei, a diverged eukaryotic microbe and important parasite, in the presence of alkylation damage caused by methyl methanesulphonate. We reveal both repair pathway conservation relative to characterised eukaryotes and specialisation, including uncharacterised roles for translesion DNA polymerases, DNA helicases and chromatin factors. Furthermore, we demonstrate that loss of around 15% of T. brucei protein kinases sensitises the parasites to alkylation, indicating phosphorylation signalling plays widespread and under-investigated roles in the damage response pathways of eukaryotes.
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