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Cook AD, Carrington M, Higgins MK. Molecular mechanism of complement inhibition by the trypanosome receptor ISG65. eLife 2024; 12:RP88960. [PMID: 38655765 DOI: 10.7554/elife.88960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
African trypanosomes replicate within infected mammals where they are exposed to the complement system. This system centres around complement C3, which is present in a soluble form in serum but becomes covalently deposited onto the surfaces of pathogens after proteolytic cleavage to C3b. Membrane-associated C3b triggers different complement-mediated effectors which promote pathogen clearance. To counter complement-mediated clearance, African trypanosomes have a cell surface receptor, ISG65, which binds to C3b and which decreases the rate of trypanosome clearance in an infection model. However, the mechanism by which ISG65 reduces C3b function has not been determined. We reveal through cryogenic electron microscopy that ISG65 has two distinct binding sites for C3b, only one of which is available in C3 and C3d. We show that ISG65 does not block the formation of C3b or the function of the C3 convertase which catalyses the surface deposition of C3b. However, we show that ISG65 forms a specific conjugate with C3b, perhaps acting as a decoy. ISG65 also occludes the binding sites for complement receptors 2 and 3, which may disrupt recruitment of immune cells, including B cells, phagocytes, and granulocytes. This suggests that ISG65 protects trypanosomes by combining multiple approaches to dampen the complement cascade.
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Affiliation(s)
- Alexander D Cook
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of Oxford, Oxford, United Kingdom
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of Oxford, Oxford, United Kingdom
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2
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Pal J, Sharma V, Khanna A, Saha S. The SET7 protein of Leishmania donovani moderates the parasite's response to a hostile oxidative environment. J Biol Chem 2024; 300:105720. [PMID: 38311179 PMCID: PMC10907163 DOI: 10.1016/j.jbc.2024.105720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/17/2024] [Accepted: 01/29/2024] [Indexed: 02/10/2024] Open
Abstract
SET domain proteins methylate specific lysines on proteins, triggering stimulation or repression of downstream processes. Twenty-nine SET domain proteins have been identified in Leishmania donovani through sequence annotations. This study initiates the first investigation into these proteins. We find LdSET7 is predominantly cytosolic. Although not essential, set7 deletion slows down promastigote growth and hypersensitizes the parasite to hydroxyurea-induced G1/S arrest. Intriguingly, set7-nulls survive more proficiently than set7+/+ parasites within host macrophages, suggesting that LdSET7 moderates parasite response to the inhospitable intracellular environment. set7-null in vitro promastigote cultures are highly tolerant to hydrogen peroxide (H2O2)-induced stress, reflected in their growth pattern, and no detectable DNA damage at H2O2 concentrations tested. This is linked to reactive oxygen species levels remaining virtually unperturbed in set7-nulls in response to H2O2 exposure, contrasting to increased reactive oxygen species in set7+/+ cells under similar conditions. In analyzing the cell's ability to scavenge hydroperoxides, we find peroxidase activity is not upregulated in response to H2O2 exposure in set7-nulls. Rather, constitutive basal levels of peroxidase activity are significantly higher in these cells, implicating this to be a factor contributing to the parasite's high tolerance to H2O2. Higher levels of peroxidase activity in set7-nulls are coupled to upregulation of tryparedoxin peroxidase transcripts. Rescue experiments using an LdSET7 mutant suggest that LdSET7 methylation activity is critical to the modulation of the cell's response to oxidative environment. Thus, LdSET7 tunes the parasite's behavior within host cells, enabling the establishment and persistence of infection without eradicating the host cell population it needs for survival.
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Affiliation(s)
- Jyoti Pal
- Department of Microbiology, University of Delhi South Campus, New Delhi, India
| | - Varshni Sharma
- Department of Microbiology, University of Delhi South Campus, New Delhi, India
| | - Arushi Khanna
- Department of Microbiology, University of Delhi South Campus, New Delhi, India
| | - Swati Saha
- Department of Microbiology, University of Delhi South Campus, New Delhi, India.
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Ciganda M, Sotelo-Silveira J, Dubey AP, Pandey P, Smith JT, Shen S, Qu J, Smircich P, Read LK. Translational control by Trypanosoma brucei DRBD18 contributes to the maintenance of the procyclic state. RNA 2023; 29:1881-1895. [PMID: 37730435 PMCID: PMC10653379 DOI: 10.1261/rna.079625.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 08/24/2023] [Indexed: 09/22/2023]
Abstract
Trypanosoma brucei occupies distinct niches throughout its life cycle, within both the mammalian and tsetse fly hosts. The immunological and biochemical complexity and variability of each of these environments require a reshaping of the protein landscape of the parasite both to evade surveillance and face changing metabolic demands. In kinetoplastid protozoa, including T. brucei, posttranscriptional control mechanisms are the primary means of gene regulation, and these are often mediated by RNA-binding proteins. DRBD18 is a T. brucei RNA-binding protein that reportedly interacts with ribosomal proteins and translation factors. Here, we tested a role for DRBD18 in translational control. We validate the DRBD18 interaction with translating ribosomes and the translation initiation factor, eIF3a. We further show that DRBD18 depletion by RNA interference leads to altered polysomal profiles with a specific depletion of heavy polysomes. Ribosome profiling analysis reveals that 101 transcripts change in translational efficiency (TE) upon DRBD18 depletion: 41 exhibit decreased TE and 60 exhibit increased TE. A further 66 transcripts are buffered, that is, changes in transcript abundance are compensated by changes in TE such that the total translational output is expected not to change. In DRBD18-depleted cells, a set of transcripts that codes for procyclic form-specific proteins is translationally repressed while, conversely, transcripts that code for bloodstream form- and metacyclic form-specific proteins are translationally enhanced. RNA immunoprecipitation/qRT-PCR indicates that DRBD18 associates with members of both repressed and enhanced cohorts. These data suggest that DRBD18 contributes to the maintenance of the procyclic state through both positive and negative translational control of specific mRNAs.
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Affiliation(s)
- Martin Ciganda
- Department of Microbiology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203, USA
| | - José Sotelo-Silveira
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo 11600, Uruguay
| | - Ashutosh P Dubey
- Department of Microbiology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203, USA
| | - Parul Pandey
- Department of Microbiology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203, USA
| | - Joseph T Smith
- Department of Microbiology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203, USA
| | - Shichen Shen
- Department of Pharmaceutical Sciences, University at Buffalo and NYS Center of Excellence in Bioinformatics and Life Sciences, Buffalo, New York 14203, USA
| | - Jun Qu
- Department of Pharmaceutical Sciences, University at Buffalo and NYS Center of Excellence in Bioinformatics and Life Sciences, Buffalo, New York 14203, USA
| | - Pablo Smircich
- Laboratorio de Bioinformática, Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo 11600, Uruguay
- Sección Genómica Funcional, Facultad de Ciencias, Universidad de la República, Montevideo 11400, Uruguay
| | - Laurie K Read
- Department of Microbiology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203, USA
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Malysheva MN, Ganyukova AI, Frolov AO, Chistyakov DV, Kostygov AY. The Mite Steatonyssus periblepharus Is a Novel Potential Vector of the Bat Parasite Trypanosoma dionisii. Microorganisms 2023; 11:2906. [PMID: 38138050 PMCID: PMC10745657 DOI: 10.3390/microorganisms11122906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/20/2023] [Accepted: 11/29/2023] [Indexed: 12/24/2023] Open
Abstract
Trypanosoma dionisii, for which only bat bugs (Cimicidae) had previously been demonstrated as vectors, was, for the first time, detected in the gamasine mite Steatonyssus periblepharus in Russia. The molecular phylogenetic analysis indicated that trypanosomes found in these mites belong to the "clade A" of T. dionisii, which, based on genetic distances, can be considered as a species separate from the sister clade B, and according to available data also has a distinct geographic distribution. The presence of developmental forms of T. dionisii resembling those previously described during the development of this trypanosome in cimicids suggests that S. periblepharus is a novel vector of the studied trypanosome.
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Affiliation(s)
- Marina N. Malysheva
- Zoological Institute of the Russian Academy of Sciences, 199034 St. Petersburg, Russia; (M.N.M.); (A.I.G.); (A.O.F.)
| | - Anna I. Ganyukova
- Zoological Institute of the Russian Academy of Sciences, 199034 St. Petersburg, Russia; (M.N.M.); (A.I.G.); (A.O.F.)
| | - Alexander O. Frolov
- Zoological Institute of the Russian Academy of Sciences, 199034 St. Petersburg, Russia; (M.N.M.); (A.I.G.); (A.O.F.)
| | - Dmitriy V. Chistyakov
- Department of Vertebrate Zoology, Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia;
| | - Alexei Yu. Kostygov
- Zoological Institute of the Russian Academy of Sciences, 199034 St. Petersburg, Russia; (M.N.M.); (A.I.G.); (A.O.F.)
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Girasol MJ, Krasilnikova M, Marques CA, Damasceno JD, Lapsley C, Lemgruber L, Burchmore R, Beraldi D, Carruthers R, Briggs EM, McCulloch R. RAD51-mediated R-loop formation acts to repair transcription-associated DNA breaks driving antigenic variation in Trypanosoma brucei. Proc Natl Acad Sci U S A 2023; 120:e2309306120. [PMID: 37988471 PMCID: PMC10691351 DOI: 10.1073/pnas.2309306120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/13/2023] [Indexed: 11/23/2023] Open
Abstract
RNA-DNA hybrids are epigenetic features of all genomes that intersect with many processes, including transcription, telomere homeostasis, and centromere function. Increasing evidence suggests that RNA-DNA hybrids can provide two conflicting roles in the maintenance and transmission of genomes: They can be the triggers of DNA damage, leading to genome change, or can aid the DNA repair processes needed to respond to DNA lesions. Evasion of host immunity by African trypanosomes, such as Trypanosoma brucei, relies on targeted recombination of silent Variant Surface Glycoprotein (VSG) genes into a specialized telomeric locus that directs transcription of just one VSG from thousands. How such VSG recombination is targeted and initiated is unclear. Here, we show that a key enzyme of T. brucei homologous recombination, RAD51, interacts with RNA-DNA hybrids. In addition, we show that RNA-DNA hybrids display a genome-wide colocalization with DNA breaks and that this relationship is impaired by mutation of RAD51. Finally, we show that RAD51 acts to repair highly abundant, localised DNA breaks at the single transcribed VSG and that mutation of RAD51 alters RNA-DNA hybrid abundance at 70 bp repeats both around the transcribed VSG and across the silent VSG archive. This work reveals a widespread, generalised role for RNA-DNA hybrids in directing RAD51 activity during recombination and uncovers a specialised application of this interplay during targeted DNA break repair needed for the critical T. brucei immune evasion reaction of antigenic variation.
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Affiliation(s)
- Mark John Girasol
- College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, University of Glasgow, GlasgowG12 8TA, United Kingdom
- Faculty of the MD-PhD in Molecular Medicine Program, College of Medicine, University of the Philippines Manila, Manila1000, Philippines
| | - Marija Krasilnikova
- College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, University of Glasgow, GlasgowG12 8TA, United Kingdom
| | - Catarina A. Marques
- College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, University of Glasgow, GlasgowG12 8TA, United Kingdom
| | - Jeziel D. Damasceno
- College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, University of Glasgow, GlasgowG12 8TA, United Kingdom
| | - Craig Lapsley
- College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, University of Glasgow, GlasgowG12 8TA, United Kingdom
| | - Leandro Lemgruber
- College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, University of Glasgow, GlasgowG12 8TA, United Kingdom
| | - Richard Burchmore
- College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, University of Glasgow, GlasgowG12 8TA, United Kingdom
| | - Dario Beraldi
- College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, University of Glasgow, GlasgowG12 8TA, United Kingdom
| | - Ross Carruthers
- College of Medical, Veterinary and Life Sciences, School of Cancer Sciences, University of Glasgow, GlasgowG12 0YN, United Kingdom
| | - Emma M. Briggs
- College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, University of Glasgow, GlasgowG12 8TA, United Kingdom
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, EdinburghEH9 3FL, United Kingdom
| | - Richard McCulloch
- College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, University of Glasgow, GlasgowG12 8TA, United Kingdom
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Wolmuth-Gordon HS, Sharmin A, Brown MJF. Methods matter: the influence of method on infection estimates of the bumblebee parasite Crithidia bombi. Parasitology 2023; 150:1236-1241. [PMID: 37859420 PMCID: PMC10941228 DOI: 10.1017/s0031182023001002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/05/2023] [Accepted: 10/16/2023] [Indexed: 10/21/2023]
Abstract
The bumblebee gut parasite, Crithidia bombi, is widespread and prevalent in the field. Its interaction with Bombus spp. is a well-established epidemiological model. It is spread faecal-orally between colonies via the shared use of flowers when foraging. Accurately measuring the level of infection in bumblebees is important for assessing its distribution in the field, and also when conducting epidemiological experiments. Studies generally use 1 of 2 methods for measuring infection. One approach measures infection in faeces whereas the other method measures infection in guts. We tested whether the method of measuring infection affected the estimation of infection. Bumblebees were inoculated with a standardized inoculum and infection was measured 1 week later using either the faecal or gut method. We found that when the gut method was used to measure infection intensity estimates were significantly different to and approximately double those from the faecal method. These results have implications for the interpretation of previous study results and for the planning of future studies. Given the importance of bumblebees as pollinators, the impact of C. bombi on bumblebee health, and its use as an epidemiological model, we call on researchers to move towards consistent quantification of infections to enable future comparisons and meta-analyses of studies.
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7
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Hargrove JW, Van Sickle J. Improved models for the relationship between age and the probability of trypanosome infection in female tsetse, Glossina pallidipes Austen. Bull Entomol Res 2023; 113:469-480. [PMID: 37194504 DOI: 10.1017/s0007485323000159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Between 1990 and 1999, at Rekomitjie Research Station, Zambezi Valley, Zimbabwe, 29,360 female G. pallidipes were dissected to determine their ovarian category and trypanosome infection status. Overall prevalences were 3.45 and 2.66% for T. vivax and T. congolense, respectively, declining during each year as temperatures increased from July - December. Fits to age-prevalence data using Susceptible-Exposed-Infective (SEI) and SI compartmental models were statistically better than those obtained using a published catalytic model, which made the unrealistic assumption that no female tsetse survived more than seven ovulations. The improved models require knowledge of fly mortality, estimated separately from ovarian category distributions. Infection rates were not significantly higher for T. vivax than for T. congolense. For T. congolense in field-sampled female G. pallidipes, we found no statistical support for a model where the force of infection was higher at the first feed than subsequently. The long survival of adult female tsetse, combined with feeding at intervals ≤3 days, ensures that post-teneral feeds, rather than the first feed, play the dominant role in the epidemiology of T. congolense infections in G. pallidipes. This is supported by estimates that only about 3% of wild hosts at Rekomitjie were harbouring sufficient T. congolense to ensure that tsetse feeding off them take an infected meal, so that the probability of ingesting an infected meal is low at every meal.
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Affiliation(s)
- J W Hargrove
- SACEMA, University of Stellenbosch, Stellenbosch, South Africa
| | - J Van Sickle
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, USA
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Halliday C, Dean S, Sunter JD, Wheeler RJ. Subcellular protein localisation of Trypanosoma brucei bloodstream form-upregulated proteins maps stage-specific adaptations. Wellcome Open Res 2023; 8:46. [PMID: 37251657 PMCID: PMC10209625 DOI: 10.12688/wellcomeopenres.18586.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2023] [Indexed: 05/31/2023] Open
Abstract
Background: Genome-wide subcellular protein localisation in Trypanosoma brucei, through our TrypTag project, has comprehensively dissected the molecular organisation of this important pathogen. Powerful as this resource is , T. brucei has multiple developmental forms and we previously only analysed the procyclic form. This is an insect life cycle stage, leaving the mammalian bloodstream form unanalysed. The expectation is that between life stages protein localisation would not change dramatically (completely unchanged or shifting to analogous stage-specific structures). However, this has not been specifically tested. Similarly, which organelles tend to contain proteins with stage-specific expression can be predicted from known stage specific adaptations but has not been comprehensively tested. Methods: We used endogenous tagging with mNG to determine the sub-cellular localisation of the majority of proteins encoded by transcripts significantly upregulated in the bloodstream form, and performed comparison to the existing localisation data in procyclic forms. Results: We have confirmed the localisation of known stage-specific proteins and identified the localisation of novel stage-specific proteins. This gave a map of which organelles tend to contain stage specific proteins: the mitochondrion for the procyclic form, and the endoplasmic reticulum, endocytic system and cell surface in the bloodstream form. Conclusions: This represents the first genome-wide map of life cycle stage-specific adaptation of organelle molecular machinery in T. brucei.
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Affiliation(s)
- Clare Halliday
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Samuel Dean
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Jack Daniel Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
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Sunter JD, Dean S, Wheeler RJ. TrypTag.org: from images to discoveries using genome-wide protein localisation in Trypanosoma brucei. Trends Parasitol 2023; 39:328-331. [PMID: 36925446 DOI: 10.1016/j.pt.2023.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 02/19/2023] [Accepted: 02/19/2023] [Indexed: 03/18/2023]
Abstract
TrypTag was a 4-year project to tag the N- and C-termini of almost all Trypanosoma brucei proteins with a fluorescent protein and record the subcellular localisation through images and manual annotation. We highlight the new routes to cell biological discovery this transformative resource is enabling for parasitologists and cell biologists.
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Affiliation(s)
- Jack D Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK.
| | - Samuel Dean
- Warwick Medical School, University of Warwick, Coventry, UK.
| | - Richard John Wheeler
- Peter Medawar Building for Pathogen Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
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Sabalette K, Sotelo-Silveira J, Smircich P, De Gaudenzi J. RNA-seq reveals that overexpression of TcUBP1 switches the gene expression pattern towards that of the infective form of Trypanosoma cruzi. J Biol Chem 2023;:104623. [PMID: 36935010 DOI: 10.1016/j.jbc.2023.104623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/19/2023] Open
Abstract
Trypanosomes regulate gene expression mainly by using post-transcriptional mechanisms. Key factors responsible for carrying out this regulation are RNA-binding proteins (RBPs), affecting subcellular localization, translation, and/or transcript stability. Trypanosoma cruzi U-rich RBP 1 (TcUBP1) is a small protein that modulates the expression of several surface glycoproteins of the trypomastigote infective stage of the parasite. Its mRNA targets are known but the impact of its overexpression at the transcriptome level in the insect-dwelling epimastigote cells has not yet been investigated. Thus, in the present study, by using a tetracycline-inducible system, we generated a population of TcUBP1-overexpressing parasites and analyzed its effect by RNA-seq methodology. This allowed us to identify 793 up- and 371 down-regulated genes with respect to the wild-type control sample. Among the up-regulated genes, it was possible to identify members coding for the TcS superfamily, MASP, MUCI/II, and protein kinases, whereas among the down-regulated transcripts, we found mainly genes coding for ribosomal, mitochondrial, and synthetic pathway proteins. RNA-seq comparison with two previously published datasets revealed that the expression profile of this TcUBP1-overexpressing replicative epimastigote form resembles the transition to the infective metacyclic trypomastigote stage. We identified novel cis-regulatory elements in the 3'-untranslated region of the affected transcripts and confirmed that UBP1m -a signature TcUBP1 binding element previously characterized in our lab- is enriched in the list of stabilized genes. We can conclude that the overall effect of TcUBP1 overexpression on the epimastigote transcriptome is mainly the stabilization of mRNAs coding for proteins that are important for parasite infection.
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Makarov A, Began J, Mautone IC, Pinto E, Ferguson L, Zoltner M, Zoll S, Field MC. The role of invariant surface glycoprotein 75 in xenobiotic acquisition by African trypanosomes. Microb Cell 2023; 10:18-35. [PMID: 36789350 PMCID: PMC9896412 DOI: 10.15698/mic2023.02.790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 01/02/2023] [Accepted: 01/13/2023] [Indexed: 02/05/2023]
Abstract
The surface proteins of parasitic protozoa mediate functions essential to survival within a host, including nutrient accumulation, environmental sensing and immune evasion. Several receptors involved in nutrient uptake and defence from the innate immune response have been described in African trypanosomes and, together with antigenic variation, contribute towards persistence within vertebrate hosts. Significantly, a superfamily of invariant surface glycoproteins (ISGs) populates the trypanosome surface, one of which, ISG75, is implicated in uptake of the century-old drug suramin. By CRISPR/Cas9 knockout and biophysical analysis, we show here that ISG75 directly binds suramin and mediates uptake of additional naphthol-related compounds, making ISG75 a conduit for entry of at least one structural class of trypanocidal compounds. However, ISG75 null cells present only modest attenuation of suramin sensitivity, have unaltered viability in vivo and in vitro and no alteration to suramin-invoked proteome responses. While ISG75 is demonstrated as a valid suramin cell entry pathway, we suggest the presence of additional mechanisms for suramin accumulation, further demonstrating the complexity of trypanosomatid drug interactions and potential for evolution of resistance.
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Affiliation(s)
- Alexandr Makarov
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Jakub Began
- Laboratory of Structural Parasitology, Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
| | - Ileana Corvo Mautone
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
- Laboratorio de Moléculas Bioactivas, Departamento de Ciencias Biológicas, Universidad de la República, Paysandú 60000, Uruguay
| | - Erika Pinto
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Liam Ferguson
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Martin Zoltner
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
- Charles University, Faculty of Science, Department of Parasitology, Vestec, Czech Republic
| | - Sebastian Zoll
- Laboratory of Structural Parasitology, Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
| | - Mark C. Field
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 Ceske Budejovice, Czech Republic
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Moses D, Mehta V, Salavati R. The discovery and characterization of two novel structural motifs on the carboxy-terminal domain of kinetoplastid RNA editing ligases. RNA 2023; 29:188-199. [PMID: 36400447 PMCID: PMC9891256 DOI: 10.1261/rna.079431.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
Parasitic protozoans of the Trypanosoma and Leishmania species have a uniquely organized mitochondrial genome, the kinetoplast. Most kinetoplast-transcribed mRNAs are cryptic and encode multiple subunits for the electron transport chain following maturation through a uridine insertion/deletion process called RNA editing. This process is achieved through an enzyme cascade by an RNA editing catalytic complex (RECC), where the final ligation step is catalyzed by the kinetoplastid RNA editing ligases, KREL1 and KREL2. While the amino-terminal domain (NTD) of these proteins is highly conserved with other DNA ligases and mRNA capping enzymes, with five recognizable motifs, the functional role of their diverged carboxy-terminal domain (CTD) has remained elusive. In this manuscript, we assayed recombinant KREL1 in vitro to unveil critical residues from its CTD to be involved in protein-protein interaction and dsRNA ligation activity. Our data show that the α-helix (H)3 of KREL1 CTD interacts with the αH1 of its editosome protein partner KREPA2. Intriguingly, the OB-fold domain and the zinc fingers on KREPA2 do not appear to influence the RNA ligation activity of KREL1. Moreover, a specific KWKE motif on the αH4 of KREL1 CTD is found to be implicated in ligase auto-adenylylation analogous to motif VI in DNA ligases. In summary, we present in the KREL1 CTD a motif VI for auto-adenylylation and a KREPA2 binding motif for RECC integration.
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Affiliation(s)
- Daniel Moses
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
| | - Vaibhav Mehta
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
- Department of Biochemistry, McGill University, Montreal, H3G 1Y6 Quebec, Canada
| | - Reza Salavati
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
- Department of Biochemistry, McGill University, Montreal, H3G 1Y6 Quebec, Canada
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Rostamighadi M, Mehta V, Hassan Khan R, Moses D, Salavati R. Hammerhead ribozyme-based U-insertion and deletion RNA editing assays for multiplexing in HTS applications. RNA 2023; 29:252-261. [PMID: 36456183 PMCID: PMC9891259 DOI: 10.1261/rna.079454.122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 11/18/2022] [Indexed: 05/14/2023]
Abstract
Untranslatable mitochondrial transcripts in kinetoplastids are decrypted post-transcriptionally through an RNA editing process that entails uridine insertion/deletion. This unique stepwise process is mediated by the editosome, a multiprotein complex that is a validated drug target of considerable interest in addressing the unmet medical needs for kinetoplastid diseases. With that objective, several in vitro RNA editing assays have been developed, albeit with limited success in discovering potent inhibitors. This manuscript describes the development of three hammerhead ribozyme (HHR) FRET reporter-based RNA editing assays for precleaved deletion, insertion, and ligation assays that bypass the rate-limiting endonucleolytic cleavage step, providing information on U-deletion, U-insertion, and ligation activities. These assays exhibit higher editing efficiencies in shorter incubation times while requiring significantly less purified editosome and 10,000-fold less ATP than the previously published full round of in vitro RNA editing assay. Moreover, modifications in the reporter ribozyme sequence enable the feasibility of multiplexing a ribozyme-based insertion/deletion editing (RIDE) assay that simultaneously surveils U-insertion and deletion editing suitable for HTS. These assays can be used to find novel chemical compounds with chemotherapeutic applications or as probes for studying the editosome machinery.
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Affiliation(s)
- Mojtaba Rostamighadi
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9
| | - Vaibhav Mehta
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada H3G 1Y6
| | - Rufaida Hassan Khan
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9
| | - Daniel Moses
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9
| | - Reza Salavati
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada H3G 1Y6
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Baker E, Hardman RH, Sutton WB, Reinsch S, Freake M, Holder E, Frost C, Nissen B, Nolan E, Gerhold R, Miller D. Prevalence and Molecular Analysis of Hellbender (Cryptobranchus alleganiensis) Trypanosomes in Tennessee. J Wildl Dis 2023. [PMID: 36602794 DOI: 10.7589/JWD-D-22-00029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 09/06/2022] [Indexed: 01/06/2023]
Abstract
Populations of eastern hellbenders (Cryptobranchus alleganiensis alleganiensis) have been declining for multiple decades because of a variety of stressors associated with anthropogenic habitat disturbance followed by riparian sedimentation. The influence of parasite-associated morbidity and mortality on wild hellbender populations is poorly understood. Research has detected widespread trypanosome infection in hellbenders in Virginia, US, with no other reported detections within the eastern hellbender's extensive range. In our study, trypanosomes mostly closely resembling Trypanosoma cryptobranchi were observed in a blood smear of a hellbender from Tennessee during a population survey. Banked whole blood from this hellbender along with 51 other hellbenders was molecularly tested for the 18s rRNA gene of amphibian trypanosomes using newly designed PCR primers. In total, 3/52 (5.8%) hellbenders were PCR- and sequence-positive for trypanosomes. This is the first report of the partial 18s rRNA sequence from hellbender trypanosomes from North America. Further research into trypanosome epidemiology and hellbender health implications is warranted.
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15
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Morenikeji OB, Metelski JL, Grytsay A, Soulas J, Akinyemi MO, Thomas BN. Molecular genotyping reveals mixed bovine and human trypanosomiasis in cattle from West Africa. Vet World 2023; 16:149-153. [PMID: 36855345 PMCID: PMC9967721 DOI: 10.14202/vetworld.2023.149-153] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 11/30/2022] [Indexed: 01/25/2023] Open
Abstract
Background and Aim Animal trypanosomiasis is a major contributor to agricultural and economic losses, especially in sub-Saharan Africa. We have shown that some animal species expressed genes that are significant players in immune response to bovine trypanosomosis, impeding signs and symptoms of the disease. We hypothesize that such animals are contributors to disease transmission dynamics and severe outcomes. Therefore, this study aims to ascertain trypanosome species diversity in cattle and their potential role as reservoirs for the transmission of human disease. Materials and Methods We performed a molecular genotyping of trypanosome internal transcribed spacer 1 (ITS-1) and 18S ribosomal RNA genes on genomic DNA extracts from randomly sampled N'Dama cattle from slaughterhouses in Nigeria. We identified trypanosome species circulating among the animals through polymerase chain reaction and genomic sequencing. We performed multiple sequence alignments as well as conducted a phylogenetic relationship between identified species. Results In all, 9 of 127 (7.1%) samples were positively amplified (band sizes ranging from 250 bp to 710 bp), including an isolate with two distinct bands (700 and 710 bp), indicating two trypanosome types. Sequence similarity and homology analysis identified four species, namely: Trypanosoma vivax, Trypanosoma congolense forest type, T. congolense savannah type, and Trypanosoma brucei. Interestingly, one of the bands, additionally verified by nucleotide sequencing, was identified as a human trypanosome (Trypanosoma brucei gambiense), confirming our hypothesis that cattle are potential reservoir hosts for human trypanosomes. Conclusion Overall, we observed different trypanosome species in our study area, with animals on the same farm infected with multiple species, which could complicate treatment and disease control strategies. Finding human trypanosome species strengthens the argument that disease transmission dynamics are modulated by other vertebrates, further complicating control programs.
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Affiliation(s)
- Olanrewaju B. Morenikeji
- Division of Biological Health Sciences, University of Pittsburgh, Bradford, PA, 16701, United States,Corresponding authors: Olanrewaju B. Morenikeji, e-mail: ; Bolaji N. Thomas, e-mail: Co-authors: JLM: , AG: , JS: , MOA:
| | - Jessica L. Metelski
- Department of Biomedical Sciences, Rochester Institute of Technology, Rochester, NY 14623, United States
| | - Anastasia Grytsay
- Division of Biological Health Sciences, University of Pittsburgh, Bradford, PA, 16701, United States
| | - Jacob Soulas
- Division of Biological Health Sciences, University of Pittsburgh, Bradford, PA, 16701, United States
| | - Mabel O. Akinyemi
- Department of Biological Sciences, Fairleigh Dickinson University, Madison, NJ 07940, United States
| | - Bolaji N. Thomas
- Department of Biomedical Sciences, Rochester Institute of Technology, Rochester, NY 14623, United States
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16
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Oliveira C, Holetz FB, Alves LR, Ávila AR. Modulation of Virulence Factors during Trypanosoma cruzi Differentiation. Pathogens 2022; 12:pathogens12010032. [PMID: 36678380 PMCID: PMC9865030 DOI: 10.3390/pathogens12010032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022] Open
Abstract
Chagas disease is a neglected tropical disease caused by Trypanosoma cruzi. This protozoan developed several mechanisms to infect, propagate, and survive in different hosts. The specific expression of proteins is responsible for morphological and metabolic changes in different parasite stages along the parasite life cycle. The virulence strategies at the cellular and molecular levels consist of molecules responsible for mediating resistance mechanisms to oxidative damage, cellular invasion, and immune evasion, performed mainly by surface proteins. Since parasite surface coat remodeling is crucial to invasion and infectivity, surface proteins are essential virulence elements. Understanding the factors involved in these processes improves the knowledge of parasite pathogenesis. Genome sequencing has opened the door to high-throughput technologies, allowing us to obtain a deeper understanding of gene reprogramming along the parasite life cycle and identify critical molecules for survival. This review therefore focuses on proteins regulated during differentiation into infective forms considered virulence factors and addresses the current known mechanisms acting in the modulation of gene expression, emphasizing mRNA signals, regulatory factors, and protein complexes.
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Affiliation(s)
- Camila Oliveira
- Laboratório de Regulação da Expressão Gênica, Instituto Carlos Chagas, Fiocruz Paraná, Curitiba 81350-010, Brazil
- Centre de Recherche CERVO, Université Laval, Québec City, QC G1V 0A6, Canada
| | - Fabíola Barbieri Holetz
- Laboratório de Regulação da Expressão Gênica, Instituto Carlos Chagas, Fiocruz Paraná, Curitiba 81350-010, Brazil
| | - Lysangela Ronalte Alves
- Laboratório de Regulação da Expressão Gênica, Instituto Carlos Chagas, Fiocruz Paraná, Curitiba 81350-010, Brazil
- Research Center in Infectious Diseases, Division of Infectious Disease and Immunity CHU de Quebec Research Center, University Laval, Québec City, QC G1V 4G2, Canada
| | - Andréa Rodrigues Ávila
- Laboratório de Pesquisa em Apicomplexa, Instituto Carlos Chagas, Fiocruz Paraná, Curitiba 81350-010, Brazil
- Correspondence: ; Tel.: +55-41-33163230
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Sortino K, Tylec BL, Chen R, Sun Y, Read LK. Conserved and transcript-specific functions of the RESC factors, RESC13 and RESC14, in kinetoplastid RNA editing. RNA 2022; 28:1496-1508. [PMID: 36096641 PMCID: PMC9745829 DOI: 10.1261/rna.079389.122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 08/28/2022] [Indexed: 05/21/2023]
Abstract
Uridine insertion/deletion RNA editing is an extensive post-transcriptional modification of mitochondrial mRNAs in kinetoplastid organisms, including Trypanosoma brucei This process is carried out using trans-acting gRNAs and complex protein machinery. The essential RNA editing substrate binding complex (RESC) serves as the scaffold that modulates protein and RNA interactions during editing, and contains the guide RNA binding complex (GRBC), the RNA editing mediator complexes (REMCs), and organizer proteins. Despite the importance of RESC in editing, the functions of each protein comprising this complex are not completely understood. Here, we further define the roles of a REMC protein, RESC13, and a RESC organizer, RESC14, using high-throughput sequencing on two large pan-edited mRNAs, A6 and COIII. When comparing our analyses to that of a previously published small pan-edited mRNA, RPS12, we find that RESC13 has conserved functions across the three transcripts with regard to editing initiation, gRNA utilization, gRNA exchange, and restricting the formation of long misedited junctions that likely arise from its ability to modulate RNA structure. However, RESC13 does have transcript-specific effects on the types of long junctions whose formation it restricts. RESC14 has a conserved effect on gRNA utilization across the three transcripts analyzed, but has transcript-specific effects on editing initiation, gRNA exchange, and junction formation. Our data suggest that transcript-specific effects of both proteins are due to differences in transcript length and sequences as well as transcript-specific protein interactions. These findings highlight the importance of studying multiple transcripts to determine the function of editing factors.
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Affiliation(s)
- Katherine Sortino
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Brianna L Tylec
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Runpu Chen
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Yijun Sun
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Laurie K Read
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
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Brown RWB, Sharma AI, Villanueva MR, Li X, Onguka O, Zilbermintz L, Nguyen H, Falk BA, Olson CL, Taylor JM, Epting CL, Kathayat RS, Amara N, Dickinson BC, Bogyo M, Engman DM. Trypanosoma brucei Acyl-Protein Thioesterase-like (TbAPT-L) Is a Lipase with Esterase Activity for Short and Medium-Chain Fatty Acids but Has No Depalmitoylation Activity. Pathogens 2022; 11:1245. [PMID: 36364996 PMCID: PMC9693859 DOI: 10.3390/pathogens11111245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/20/2022] [Accepted: 10/24/2022] [Indexed: 02/12/2024] Open
Abstract
Dynamic post-translational modifications allow the rapid, specific, and tunable regulation of protein functions in eukaryotic cells. S-acylation is the only reversible lipid modification of proteins, in which a fatty acid, usually palmitate, is covalently attached to a cysteine residue of a protein by a zDHHC palmitoyl acyltransferase enzyme. Depalmitoylation is required for acylation homeostasis and is catalyzed by an enzyme from the alpha/beta hydrolase family of proteins usually acyl-protein thioesterase (APT1). The enzyme responsible for depalmitoylation in Trypanosoma brucei parasites is currently unknown. We demonstrate depalmitoylation activity in live bloodstream and procyclic form trypanosomes sensitive to dose-dependent inhibition with the depalmitoylation inhibitor, palmostatin B. We identified a homologue of human APT1 in Trypanosoma brucei which we named TbAPT-like (TbAPT-L). Epitope-tagging of TbAPT-L at N- and C- termini indicated a cytoplasmic localization. Knockdown or over-expression of TbAPT-L in bloodstream forms led to robust changes in TbAPT-L mRNA and protein expression but had no effect on parasite growth in vitro, or cellular depalmitoylation activity. Esterase activity in cell lysates was also unchanged when TbAPT-L was modulated. Unexpectedly, recombinant TbAPT-L possesses esterase activity with specificity for short- and medium-chain fatty acid substrates, leading to the conclusion, TbAPT-L is a lipase, not a depalmitoylase.
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Affiliation(s)
- Robert W. B. Brown
- Departments of Pathology, Microbiology-Immunology and Pediatrics, Northwestern University, Chicago, IL 60611, USA
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Aabha I. Sharma
- Departments of Pathology, Microbiology-Immunology and Pediatrics, Northwestern University, Chicago, IL 60611, USA
| | - Miguel Rey Villanueva
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Xiaomo Li
- Departments of Pathology, Microbiology-Immunology and Pediatrics, Northwestern University, Chicago, IL 60611, USA
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Ouma Onguka
- Departments of Pathology and Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Leeor Zilbermintz
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Helen Nguyen
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Ben A. Falk
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Cheryl L. Olson
- Departments of Pathology, Microbiology-Immunology and Pediatrics, Northwestern University, Chicago, IL 60611, USA
| | - Joann M. Taylor
- Departments of Pathology, Microbiology-Immunology and Pediatrics, Northwestern University, Chicago, IL 60611, USA
| | - Conrad L. Epting
- Departments of Pathology, Microbiology-Immunology and Pediatrics, Northwestern University, Chicago, IL 60611, USA
| | - Rahul S. Kathayat
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA
| | - Neri Amara
- Departments of Pathology and Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Bryan C. Dickinson
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA
| | - Matthew Bogyo
- Departments of Pathology and Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - David M. Engman
- Departments of Pathology, Microbiology-Immunology and Pediatrics, Northwestern University, Chicago, IL 60611, USA
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
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Bishola Tshitenge T, Clayton C. The Trypanosoma brucei RNA-binding protein DRBD18 ensures correct mRNA trans splicing and polyadenylation patterns. RNA 2022; 28:1239-1262. [PMID: 35793904 PMCID: PMC9380746 DOI: 10.1261/rna.079258.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
The parasite Trypanosoma brucei grows as bloodstream forms in mammals, and as procyclic forms in tsetse flies. Transcription is polycistronic, all mRNAs are trans spliced, and polyadenylation sites are defined by downstream splicing signals. Expression regulation therefore depends heavily on post-transcriptional mechanisms. The RNA-binding protein DRBD18 was previously implicated in the export of some mRNAs from the nucleus in procyclic forms. It copurifies the outer ring of the nuclear pore, mRNA export factors and exon-junction-complex proteins. We show that for more than 200 mRNAs, DRBD18 depletion caused preferential accumulation of versions with shortened 3'-untranslated regions, arising from use of polyadenylation sites that were either undetectable or rarely seen in nondepleted cells. The shortened mRNAs were often, but not always, more abundant in depleted cells than the corresponding longer versions in normal cells. Their appearance was linked to the appearance of trans-spliced, polyadenylated RNAs containing only downstream 3'-untranslated region-derived sequences. Experiments with one mRNA suggested that nuclear retention alone, through depletion of MEX67, did not affect mRNA length, suggesting a specific effect of DRBD18 on processing. DRBD18-bound mRNAs were enriched in polypyrimidine tract motifs, and DRBD18 was found in both the nucleus and the cytoplasm. We therefore suggest that in the nucleus, DRBD18 might bind to polypyrimidine tracts in 3'-UTRs of mRNA precursors. Such binding might both prevent recognition of mRNA-internal polypyrimidine tracts by splicing factors, and promote export of the processed bound mRNAs to the cytosol.
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Affiliation(s)
| | - Christine Clayton
- Heidelberg University Center for Molecular Biology (ZMBH), D69120 Heidelberg, Germany
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20
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Abstract
A hallmark of eukaryotic cells is the ability to form a secretory pathway connecting many intracellular compartments. In the early secretory pathway, coated protein complex II (COPII)-coated vesicles mediate the anterograde transport of newly synthesized secretory cargo from the endoplasmic reticulum to the Golgi apparatus. The COPII coat complex is comprised of an inner layer of Sec23/Sec24 heterodimers and an outer layer of Sec13/Sec31 heterotetramers. In African trypanosomes, there are two paralogues each of Sec23 and Sec24, that form obligate heterodimers (TbSec23.2/TbSec24.1, TbSec23.1/TbSec24.2). It is not known if these form distinct homotypic classes of vesicles or one heterotypic class, but it is known that TbSec23.2/TbSec24.1 specifically mediate forward trafficking of GPI-anchored proteins (GPI-APs) in bloodstream-form trypanosomes (BSF). Here, we showed that this selectivity was lost in insect procyclic stage parasites (PCF). All isoforms of TbSec23 and TbSec24 are essential in PCF parasites as judged by RNAi knockdowns. RNAi silencing of each subunit had equivalent effects on the trafficking of GPI-APs and p67, a transmembrane lysosomal protein. However, silencing of the TbSec23.2/TbSec24.1 had heterodimer had a significant impact on COPII mediated trafficking of soluble TbCatL from the ER to the lysosome. This finding suggests a model in which selectivity of COPII transport was altered between the BSF and PCF trypanosomes, possibly as an adaptation to a digenetic life cycle. IMPORTANCE African trypanosomes synthesize dense surface coats composed of stage-specific glycosylphosphatidylinositol lipid anchored proteins. We previously defined specific machinery in bloodstream stage parasites that mediate the exit of these proteins from the endoplasmic reticulum. Here, we performed similar analyses in the procyclic insect stage and found significant differences in this process. These findings contribute to our understanding of secretory processes in this unusual eukaryotic model system.
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Sharif M, Garrison P, Bush P, Bangs JD. Turnover of Variant Surface Glycoprotein in Trypanosoma brucei Is Not Altered in Response to Specific Silencing. mSphere 2022;:e0012222. [PMID: 35727016 DOI: 10.1128/msphere.00122-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
African trypanosomes evade the immune system of the mammalian host by the antigenic variation of the predominant glycosylphosphatidylinositol (GPI)-anchored surface protein, variant surface glycoprotein (VSG). VSG is a very stable protein that is turned over from the cell surface with a long half-life (~26 h), allowing newly synthesized VSG to populate the surface. We have recently demonstrated that VSG turnover under normal growth is mediated by a combination of GPI hydrolysis and direct shedding with intact GPI anchors. VSG synthesis is tightly regulated in dividing trypanosomes, and when subjected to RNA interference (RNAi) silencing, cells display rapid cell cycle arrest in order to conserve VSG density on the cell surface (K. Sheader, S. Vaughan, J. Minchin, K. Hughes, et al., Proc Natl Acad Sci U S A 102:8716-8721, 2005, https://doi.org/10.1073/pnas.0501886102). Arrested cells also display an altered morphology of secretory organelles-engorgement of the trans-Golgi cisternae-that may reflect a disruption of post-Golgi secretory transport. We now ask whether trypanosomes under VSG silencing also reduce the rate of VSG turnover to further conserve coat density. Our data indicate that trypanosomes do not regulate VSG turnover according to VSG protein abundance, nor was there any effect on the post-Golgi transport of soluble or GPI-anchored secretory cargo. However, the surface morphology of silenced cells was altered from a typically rugose topology to a smoother profile, consistent with reduced overall membrane trafficking to the cell surface. IMPORTANCE African trypanosomes evade the host immune system by altering the expression of variant surface glycoproteins (VSGs) in a process called antigenic variation. VSG is essential, and when its synthesis is ablated by RNAi silencing, cells enter precytokinesis growth arrest as a means to maintain constant cell surface VSG levels. We have investigated whether arrested cells also alter the rate of natural VSG turnover as a means to conserve the surface coat. This work provides insights into the natural biology of the glycocalyx of this important human and veterinary parasite.
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22
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Bemba I, Bamou R, Lenga A, Okoko A, Awono-Ambene P, Antonio-Nkondjio C. Review of the Situation of Human African Trypanosomiasis in the Republic of Congo From the 1950s to 2020. J Med Entomol 2022; 59:421-429. [PMID: 35137146 PMCID: PMC8924973 DOI: 10.1093/jme/tjab225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Indexed: 06/14/2023]
Abstract
Human African trypanosomiasis (HAT), despite considerable progress in the control, is still occurring in many countries in both west and central African regions. The HAT situation in the Republic of Congo has always been overshadowed by its neighbor the Democratic Republic of Congo where over 60% of all HAT cases occur. In the Republic of Congo, HAT cases have been significantly reduced to about 20 reported cases yearly and the disease is still prevalent in few foci across the country. Although continuous assessment of HAT situation in Congo is been led by the National Control Program for HAT, research on the vector, parasite, and vector control has received little attention. Because there have not been enough reviews summarizing key findings from studies conducted so far, there is still a poor understanding of the global situation of HAT in Congo. In order to achieve sustainable elimination of HAT in Congo a deep appraisal of HAT situation is required. The present study provides a review of studies conducted on HAT in the republic of Congo since the 1950s to date in order to identify gaps in knowledge and help consolidate the gains and progress towards the elimination of sleeping sickness.
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Affiliation(s)
- Irina Bemba
- Marien Ngouabi University, B.P. 69, Brazzaville, Republic of Congo
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroun
| | - Roland Bamou
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroun
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science of the University of Dschang, P.O. Box 067, Cameroon
| | - Arsene Lenga
- Marien Ngouabi University, B.P. 69, Brazzaville, Republic of Congo
| | - Aline Okoko
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroun
| | - Parfait Awono-Ambene
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroun
| | - Christophe Antonio-Nkondjio
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroun
- Vector Biology Liverpool School of Tropical medicine Pembroke Place, Liverpool, UK
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Garrison P, Khan U, Cipriano M, Bush PJ, McDonald J, Sur A, Myler PJ, Smith TK, Hajduk SL, Bangs JD. Turnover of Variant Surface Glycoprotein in Trypanosoma brucei Is a Bimodal Process. mBio 2021; 12:e0172521. [PMID: 34311578 DOI: 10.1128/mBio.01725-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
African trypanosomes utilize glycosylphosphatidylinositol (GPI)-anchored variant surface glycoprotein (VSG) to evade the host immune system. VSG turnover is thought to be mediated via cleavage of the GPI anchor by endogenous GPI-specific phospholipase C (GPI-PLC). However, GPI-PLC is topologically sequestered from VSG substrates in intact cells. Recently, A. J. Szempruch, S. E. Sykes, R. Kieft, L. Dennison, et al. (Cell 164:246–257, 2016, https://doi.org/10.1016/j.cell.2015.11.051) demonstrated the release of nanotubes that septate to form free VSG+ extracellular vesicles (EVs). Here, we evaluated the relative contributions of GPI hydrolysis and EV formation to VSG turnover in wild-type (WT) and GPI-PLC null cells. The turnover rate of VSG was consistent with prior measurements (half-life [t1/2] of ∼26 h) but dropped significantly in the absence of GPI-PLC (t1/2 of ∼36 h). Ectopic complementation restored normal turnover rates, confirming the role of GPI-PLC in turnover. However, physical characterization of shed VSG in WT cells indicated that at least 50% is released directly from cell membranes with intact GPI anchors. Shedding of EVs plays an insignificant role in total VSG turnover in both WT and null cells. In additional studies, GPI-PLC was found to have no role in biosynthetic and endocytic trafficking to the lysosome but did influence the rate of receptor-mediated endocytosis. These results indicate that VSG turnover is a bimodal process involving both direct shedding and GPI hydrolysis.
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25
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Banerjee H, LaPointe P, Eitzen G, Rachubinski RA. A Small Molecule Inhibitor of Pex3-Pex19 Interaction Disrupts Glycosome Biogenesis and Causes Lethality in Trypanosoma brucei. Front Cell Dev Biol 2021; 9:703603. [PMID: 34350186 PMCID: PMC8326762 DOI: 10.3389/fcell.2021.703603] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/22/2021] [Indexed: 11/29/2022] Open
Abstract
Trypanosomatid parasites, including Trypanosoma and Leishmania, are infectious zoonotic agents for a number of severe diseases such as African sleeping sickness and American trypanosomiasis (Chagas disease) that affect millions of people, mostly in the emergent world. The glycosome is a specialized member of the peroxisome family of organelles found in trypanosomatids. These organelles compartmentalize essential enzymes of the glycolytic pathway, making them a prime target for drugs that can kill these organisms by interfering with either their biochemical functions or their formation. Glycosome biogenesis, like peroxisome biogenesis, is controlled by a group of proteins called peroxins (Pex). Pex3 is an early acting peroxin that docks Pex19, the receptor for peroxisomal membrane proteins, to initiate biogenesis of peroxisomes from the endoplasmic reticulum. Identification of Pex3 as the essential master regulator of glycosome biogenesis has implications in developing small molecule inhibitors that can impede Pex3–Pex19 interaction. Low amino acid sequence conservation between trypanosomatid Pex3 and human Pex3 (HsPex3) would aid in the identification of small molecule inhibitors that selectively interfere with the trypanosomatid Pex3–Pex19 interaction. We tested a library of pharmacologically active compounds in a modified yeast two-hybrid assay and identified a compound that preferentially inhibited the interaction of Trypanosoma brucei Pex3 and Pex19 versus HsPex3 and Pex19. Addition of this compound to either the insect or bloodstream form of T. brucei disrupted glycosome biogenesis, leading to mislocalization of glycosomal enzymes to the cytosol and lethality for the parasite. Our results show that preferential disruption of trypanosomal Pex3 function by small molecule inhibitors could help in the accelerated development of drugs for the treatment of trypanosomiases.
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Affiliation(s)
- Hiren Banerjee
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Paul LaPointe
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Gary Eitzen
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
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26
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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27
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Umaer K, Aresta-Branco F, Chandra M, van Straaten M, Zeelen J, Lapouge K, Waxman B, Stebbins CE, Bangs JD. Dynamic, variable oligomerization and the trafficking of variant surface glycoproteins of Trypanosoma brucei. Traffic 2021; 22:274-283. [PMID: 34101314 DOI: 10.1111/tra.12806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 05/14/2021] [Accepted: 06/04/2021] [Indexed: 12/20/2022]
Abstract
African trypanosomes cause disease in humans and livestock, avoiding host immunity by changing the expression of variant surface glycoproteins (VSGs); the major glycosylphosphatidylinositol (GPI) anchored antigens coating the surface of the bloodstream stage. Proper trafficking of VSGs is therefore critical to pathogen survival. The valence model argues that GPI anchors regulate progression and fate in the secretory pathway and that, specifically, a valence of two (VSGs are dimers) is critical for stable cell surface association. However, recent reports that the MITat1.3 (M1.3) VSG N-terminal domain (NTD) behaves as a monomer in solution and in a crystal structure challenge this model. We now show that the behavior of intact M1.3 VSG in standard in vivo trafficking assays is consistent with an oligomer. Nevertheless, Blue Native Gel electrophoresis and size exclusion chromatography-multiangle light scattering chromatography of purified full length M1.3 VSG indicates a monomer in vitro. However, studies with additional VSGs show that multiple oligomeric states are possible, and that for some VSGs oligomerization is concentration dependent. These data argue that individual VSG monomers possess different propensities to self-oligomerize, but that when constrained at high density to the cell surface, oligomeric species predominate. These results resolve the apparent conflict between the valence hypothesis and the M1.3 NTD VSG crystal structure.
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Affiliation(s)
- Khan Umaer
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York, USA.,Eurofins, Spring House, Pennsylvania, USA
| | - Francisco Aresta-Branco
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany.,Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - Monica Chandra
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany.,Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
| | - Monique van Straaten
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Johan Zeelen
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Karine Lapouge
- Protein Expression and Purification Core Facility, EMBL Heidelberg, Heidelberg, Germany
| | - Brandon Waxman
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York, USA
| | - C Erec Stebbins
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - James D Bangs
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York, USA
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28
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Mishra A, Kaur JN, McSkimming DI, Hegedűsová E, Dubey AP, Ciganda M, Paris Z, Read LK. Selective nuclear export of mRNAs is promoted by DRBD18 in Trypanosoma brucei. Mol Microbiol 2021; 116:827-840. [PMID: 34146438 DOI: 10.1111/mmi.14773] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 06/04/2021] [Accepted: 06/18/2021] [Indexed: 11/27/2022]
Abstract
Kinetoplastids, including Trypanosoma brucei, control gene expression primarily at the posttranscriptional level. Nuclear mRNA export is an important, but understudied, step in this process. The general heterodimeric export factors, Mex67/Mtr2, function in the export of mRNAs and tRNAs in T. brucei, but RNA binding proteins (RBPs) that regulate export processes by controlling the dynamics of Mex67/Mtr2 ribonucleoprotein formation or transport have not been identified. Here, we report that DRBD18, an essential and abundant T. brucei RBP, associates with Mex67/Mtr2 in vivo, likely through its direct interaction with Mtr2. DRBD18 downregulation results in partial accumulation of poly(A)+ mRNA in the nucleus, but has no effect on the localization of intron-containing or mature tRNAs. Comprehensive analysis of transcriptomes from whole-cell and cytosol in DRBD18 knockdown parasites demonstrates that depletion of DRBD18 leads to impairment of nuclear export of a subset of mRNAs. CLIP experiments reveal the association of DRBD18 with several of these mRNAs. Moreover, DRBD18 knockdown leads to a partial accumulation of the Mex67/Mtr2 export receptors in the nucleus. Taken together, the current study supports a model in which DRBD18 regulates the selective nuclear export of mRNAs by promoting the mobilization of export competent mRNPs to the cytosol through the nuclear pore complex.
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Affiliation(s)
- Amartya Mishra
- Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Jan Naseer Kaur
- Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Daniel I McSkimming
- Bioinformatics and Computational Biology Core, University of Southern Florida, Tampa, FL, USA
| | - Eva Hegedűsová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
| | - Ashutosh P Dubey
- Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Martin Ciganda
- Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Laurie K Read
- Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
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29
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Walsh B, Hill KL. Right place, right time: Environmental sensing and signal transduction directs cellular differentiation and motility in Trypanosoma brucei. Mol Microbiol 2021; 115:930-941. [PMID: 33434370 DOI: 10.1111/mmi.14682] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 11/29/2022]
Abstract
Trypanosoma brucei and other African trypanosomes are vector-borne parasites that cause substantial human suffering across sub-Saharan Africa. The T. brucei life cycle is punctuated by numerous developmental stages, each occurring in a specific environmental niche and characterized by a unique morphology, metabolism, surface protein coat, and gene expression profile. The environmental cues and signaling pathways that drive transitions between these stages remain incompletely understood. Recent studies have started to fill this gap in knowledge. Likewise, several new studies have expanded our understanding of parasite movement through specific tissues and the parasite's ability to alter movement in response to external cues. Life cycle stage differentiation and motility are intimately integrated phenomena, as parasites must be at the right place (i.e., within a specific environmental milieu) at the right time (i.e., when they are appropriately staged and preadapted for perceiving and responding to signals) in order to complete their life cycle. In this review, we highlight some of the recent work that has transformed our understanding of signaling events that control parasite differentiation and motility. Increased knowledge of T. brucei environmental sensing and signal transduction advances our understanding of parasite biology and may direct prospective chemotherapeutic and transmission blockade strategies that are critical to eradication efforts.
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Affiliation(s)
- Breanna Walsh
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA.,Medical Scientist Training Program, University of California Los Angeles, Los Angeles, CA, USA
| | - Kent L Hill
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA.,California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, USA
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30
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Jacobs SH, Dóró E, Hammond FR, Nguyen-Chi ME, Lutfalla G, Wiegertjes GF, Forlenza M. Occurrence of foamy macrophages during the innate response of zebrafish to trypanosome infections. eLife 2021; 10:64520. [PMID: 34114560 PMCID: PMC8238505 DOI: 10.7554/elife.64520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 06/09/2021] [Indexed: 12/19/2022] Open
Abstract
A tightly regulated innate immune response to trypanosome infections is critical to strike a balance between parasite control and inflammation-associated pathology. In this study, we make use of the recently established Trypanosoma carassii infection model in larval zebrafish to study the early response of macrophages and neutrophils to trypanosome infections in vivo. We consistently identified high- and low-infected individuals and were able to simultaneously characterise their differential innate response. Not only did macrophage and neutrophil number and distribution differ between the two groups, but also macrophage morphology and activation state. Exclusive to high-infected zebrafish, was the occurrence of foamy macrophages characterised by a strong pro-inflammatory profile and potentially associated with an exacerbated immune response as well as susceptibility to the infection. To our knowledge, this is the first report of the occurrence of foamy macrophages during an extracellular trypanosome infection.
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Affiliation(s)
- Sem H Jacobs
- Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University & Research, Wageningen, Netherlands.,Experimental Zoology Group, Department of Animal Sciences, Wageningen University & Research, Wageningen, Netherlands
| | - Eva Dóró
- Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University & Research, Wageningen, Netherlands
| | - Ffion R Hammond
- Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University & Research, Wageningen, Netherlands
| | | | | | - Geert F Wiegertjes
- Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University & Research, Wageningen, Netherlands.,Aquaculture and Fisheries Group, Department of Animal Sciences, Wageningen University & Research, Wageningen, Netherlands
| | - Maria Forlenza
- Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University & Research, Wageningen, Netherlands
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31
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Aphasizheva I, Aphasizhev R. Mitochondrial RNA quality control in trypanosomes. Wiley Interdiscip Rev RNA 2021; 12:e1638. [PMID: 33331073 PMCID: PMC9805618 DOI: 10.1002/wrna.1638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/27/2020] [Accepted: 11/29/2020] [Indexed: 01/04/2023]
Abstract
Unicellular parasites Trypanosoma brucei spp. cause African human and animal trypanosomiasis, a spectrum of diseases that jeopardize public health and afflict the economy in sub-Saharan Africa. These hemoflagellates are distinguished by a single mitochondrion, which contains a kinetoplast nucleoid composed of DNA and histone-like proteins. Kinetoplast DNA (kDNA) represents a densely packed network of interlinked relaxed circular molecules: a few ~23-kb maxicircles encoding ribosomal RNAs (rRNAs) and proteins, and approximately 5,000 1-kb minicircles bearing guide RNA (gRNA) genes. The transcription start site defines the mRNA's 5' terminus while the primary RNA is remodeled into a monocistronic messenger by 3'-5' exonucleolytic trimming, 5' and 3' end modifications, and, in most cases, by internal U-insertion/deletion editing. Ribosomal and guide RNA precursors are also trimmed, and the processed molecules are uridylated. For 35 years, mRNA editing has attracted a major effort, but more recently the essential pre- and postediting processing and turnover events have been discovered and the key effectors have been identified. Among these, pentatricopeptide repeat (PPR) RNA binding proteins emerged as conduits coupling modifications of mRNA termini with internal sequence changes introduced by editing. Among 39 annotated PPRs, 20 belong to ribosomal subunits or assembly intermediates, four function as polyadenylation factors, a single factor directs 5' mRNA modification, and one protein is found in F1-ATPase. Nuclear and mitochondrial RNases P consist of a single PPR polypeptide, PRORP1 and PROP2, respectively. Here, we review PPR-mediated mitochondrial processes and discuss their potential roles in mRNA maturation, quality control, translational activation, and decay. This article is categorized under: RNA Processing > Capping and 5' End Modifications RNA Processing > 3' End Processing RNA Processing > RNA Editing and Modification.
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Affiliation(s)
- Inna Aphasizheva
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, Massachusetts
| | - Ruslan Aphasizhev
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, Massachusetts,Department of Biochemistry, Boston University Medical Campus, Boston, Massachusetts
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32
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Golnar AJ, Medeiros MCI, Rosenbaum K, Bejcek J, Hamer SA, Hamer GL. Vector-Borne Blood Parasites of the Great-Tailed Grackle ( Quiscalus mexicanus) in East-Central Texas, USA. Microorganisms 2021; 9:504. [PMID: 33673608 DOI: 10.3390/microorganisms9030504] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 12/29/2022] Open
Abstract
Great-tailed grackles (Quiscalus mexicanus) have dramatically expanded into North America over the past century. However, little is known about the blood that parasites they support. Here, for the first time, we document an assemblage of trypanosome, haemosporida, and filarial nematodes co-circulating in invasive great-tailed grackles. Between February and July, 2015, 61 individuals were captured in an urban environment of College Station, Texas. Field microscopy and molecular diagnostics indicate that 52% (24/46) were visually infected with filarioid nematodes, 24% (11/46) with avian trypanosomes, and 73% (n = 44/60) with haemosporida parasites, such as Haemoproteus (Parahaemoproteus) and Plasmodium cathemerium. Overall, 87% of great-tailed grackles were infected with blood parasites. Although 50% of individuals hosted parasites from multiple phylum, no patterns of parasite assembly were observed. Results indicate that great-tailed grackles can support a relatively high level of blood parasitism. However, the consequences for avian health remain to be determined.
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Abstract
p67 is a type I transmembrane glycoprotein of the terminal lysosome of African trypanosomes. Its biosynthesis involves transport of an initial gp100 ER precursor to the lysosome, followed by cleavage to N-terminal (gp32) and C-terminal (gp42) subunits that remain non-covalently associated. p67 knockdown is lethal, but the only overt phenotype is an enlarged lysosome (~250 to >1000 nm). Orthologues have been characterized in Dictyostelium and mammals. These have processing pathways similar to p67, and are thought to have phospholipase B-like (PLBL) activity. The mouse PLBD2 crystal structure revealed that the PLBLs represent a subgroup of the larger N-terminal nucleophile (NTN) superfamily, all of which are hydrolases. NTNs activate by internal autocleavage mediated by a nucleophilic residue, i.e. Cys, Ser or Thr, on the upstream peptide bond to form N-terminal α (gp32) and C-terminal β (gp42) subunits that remain non-covalently associated. The N-terminal residue of the β subunit is then catalytic in subsequent hydrolysis reactions. All PLBLs have a conserved Cys/Ser dipeptide at the α/β junction (Cys241/Ser242 in p67), mutation of which renders p67 non-functional in RNAi rescue assays. p67 orthologues are found in many clades of parasitic protozoa, thus p67 is the founding member of a group of hydrolases that likely play a role broadly in the pathogenesis of parasitic infections.
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34
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Garrison P, Bangs JD. p97 Inhibitor CB-5083 Blocks ERAD in Trypanosoma brucei. Mol Biochem Parasitol 2020; 239:111313. [PMID: 32735998 DOI: 10.1016/j.molbiopara.2020.111313] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/22/2020] [Accepted: 07/23/2020] [Indexed: 11/26/2022]
Abstract
Misfolded proteins trapped in the endoplasmic reticulum (ER) are specifically recognized and retrotranslocated to the cytosol by the ER-Associated Degradation (ERAD) system and delivered to the proteasome for destruction. This process was recently described in Trypanosoma brucei (T. brucei) using the misfolded epitope tagged Transferrin Receptor subunits ESAG7:Ty and HA:ESAG6 (HA:E6). Critical to this work was the proteasomal inhibitor MG132. However, MG132 has off-target inhibitory effects on lysosomal Cathepsin L that could cause misinterpretation of turnover results. Here, we evaluate an orally bioavailable p97 inhibitor, CB-5083, for use in T. brucei. p97 is a ubiquitous protein involved in many cellular events including the membrane extraction step of ERAD. CB-5083 strongly inhibits turnover of HA:E6, with comparable protein recovery to MG132 treatment. Interestingly, little deglycosylated cytoplasmic species accumulates, though it normally emerges with MG132 treatment. This suggests that CB-5083 blocks ERAD upstream of the proteasome, as expected for inhibition of the trypanosomal p97 orthologue TbVCP. Under CB-5083 treatment, HA:E6 is also strongly membrane-associated, suggesting ER localization. Finally, we provide an experimental example where CB-5083 treatment offers clarity to the off-target effects of MG132 treatment.
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Affiliation(s)
- Paige Garrison
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, 14203, USA
| | - James D Bangs
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, 14203, USA.
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35
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Pham KTM, Hu H, Li Z. Maintenance of hook complex integrity and centrin arm assembly facilitates flagellum inheritance in Trypanosoma brucei. J Biol Chem 2020; 295:12962-12974. [PMID: 32675283 DOI: 10.1074/jbc.ra120.014237] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/08/2020] [Indexed: 11/06/2022] Open
Abstract
Inheritance of the newly assembled flagellum in the human parasite Trypanosoma brucei depends on the faithful duplication and segregation of multiple flagellum-associated cytoskeletal structures, including the hook complex and its associated centrin arm. The biological functions of this unique hook complex-centrin arm assembly remain poorly understood. Here, we report a hook complex-associated protein named BOH2 that plays an essential role in promoting flagellum inheritance. BOH2 localizes to the hooked part of the hook complex by bridging the hook complex, the centrin arm, and the flagellum attachment zone filament. Depletion of BOH2 caused the loss of the shank part of the hook complex and its associated protein TbSmee1, disrupted the assembly of the centrin arm and the recruitment of centrin arm-associated protein CAAP1, inhibited the assembly of the flagellum attachment zone, and caused flagellum mispositioning and detachment. These results demonstrate crucial roles of BOH2 in maintaining hook complex integrity and promoting centrin arm formation and suggest that proper assembly of the hook complex-centrin arm structure facilitates flagellum inheritance.
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Affiliation(s)
- Kieu T M Pham
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Huiqing Hu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Ziyin Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA.
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Arismendi N, Caro S, Castro MP, Vargas M, Riveros G, Venegas T. Impact of Mixed Infections of Gut Parasites Lotmaria passim and Nosema ceranae on the Lifespan and Immune-related Biomarkers in Apis mellifera. Insects 2020; 11:E420. [PMID: 32650366 DOI: 10.3390/insects11070420] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 12/17/2022]
Abstract
Lotmaria passim currently appears to be the predominant trypanosome in honey bees worldwide. Although, the specific effects of L. passim by single or mixed with other gut parasites such as Nosema ceranae on honey bees’ health is still unclear. We consequently measured bees’ survival, parasite loads, the expression of antimicrobial peptides (AMPs) and vitellogenin gene. Thus, (1) bees naturally infected with L. passim, (2) healthy bees inoculated with Nosema ceranae, (3) bees naturally infected with L. passim and inoculated with N. ceranae and (4) healthy bees (control) were maintained under controlled conditions. Honey bees infected with N. ceranae or with mixed infections of L. passim and N. ceranae had significantly lower survival rates than the control group at 20 days post-inoculation (dpi). A competitive suppression was also detected, provided that the L. passim load was significantly affected by the presence of N. ceranae at 15 dpi. Expressions of the AMPs defensin and hymenoptaecin rapidly (two hours post-inoculation) increased in bees infected with N. ceranae and mixed infections. However, this effect was not continuous. In fact, expressions of abaecin, defensin, hymenoptaecin and vitellogenin decreased drastically at 15 dpi in bees with both single and mixed infections. The decrease in the expression of AMPs and vitellogenin throughout this period was consistent with the reduced survivals observed in this study, indicating that mixed infections of L. passim and N. ceranae, and even into a scenario of competition between them, may have a synergic effect on the survival and immune-related gene expressions (biomarkers) of worker bees.
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Mehta V, Moshiri H, Srikanth A, Kala S, Lukeš J, Salavati R. Sulfonated inhibitors of the RNA editing ligases validate the essential role of the MRP1/2 proteins in kinetoplastid RNA editing. RNA 2020; 26:827-835. [PMID: 32276989 PMCID: PMC7297121 DOI: 10.1261/rna.075598.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 04/06/2020] [Indexed: 05/21/2023]
Abstract
The RNA editing core complex (RECC) catalyzes mitochondrial U-insertion/deletion mRNA editing in trypanosomatid flagellates. Some naphthalene-based sulfonated compounds, such as C35 and MrB, competitively inhibit the auto-adenylylation activity of an essential RECC enzyme, kinetoplastid RNA editing ligase 1 (KREL1), required for the final step in editing. Previous studies revealed the ability of these compounds to interfere with the interaction between the editosome and its RNA substrates, consequently affecting all catalytic activities that comprise RNA editing. This observation implicates a critical function for the affected RNA binding proteins in RNA editing. In this study, using the inhibitory compounds, we analyzed the composition and editing activities of functional editosomes and identified the mitochondrial RNA binding proteins 1 and 2 (MRP1/2) as their preferred targets. While the MRP1/2 heterotetramer complex is known to bind guide RNA and promote annealing to its cognate pre-edited mRNA, its role in RNA editing remained enigmatic. We show that the compounds affect the association between the RECC and MRP1/2 heterotetramer. Furthermore, RECC purified post-treatment with these compounds exhibit compromised in vitro RNA editing activity that, remarkably, recovers upon the addition of recombinant MRP1/2 proteins. This work provides experimental evidence that the MRP1/2 heterotetramer is required for in vitro RNA editing activity and substantiates the hypothesized role of these proteins in presenting the RNA duplex to the catalytic complex in the initial steps of RNA editing.
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Affiliation(s)
- Vaibhav Mehta
- Department of Biochemistry, McGill University, Montreal, H3G1Y6 Quebec, Canada
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
| | - Houtan Moshiri
- Department of Biochemistry, McGill University, Montreal, H3G1Y6 Quebec, Canada
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
| | - Akshaya Srikanth
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
| | - Smriti Kala
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre and Faculty of Science, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
| | - Reza Salavati
- Department of Biochemistry, McGill University, Montreal, H3G1Y6 Quebec, Canada
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
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Zoltner M, Campagnaro GD, Taleva G, Burrell A, Cerone M, Leung KF, Achcar F, Horn D, Vaughan S, Gadelha C, Zíková A, Barrett MP, de Koning HP, Field MC. Suramin exposure alters cellular metabolism and mitochondrial energy production in African trypanosomes. J Biol Chem 2020; 295:8331-8347. [PMID: 32354742 PMCID: PMC7294092 DOI: 10.1074/jbc.ra120.012355] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 04/21/2020] [Indexed: 12/27/2022] Open
Abstract
Introduced about a century ago, suramin remains a frontline drug for the management of early-stage East African trypanosomiasis (sleeping sickness). Cellular entry into the causative agent, the protozoan parasite Trypanosoma brucei, occurs through receptor-mediated endocytosis involving the parasite's invariant surface glycoprotein 75 (ISG75), followed by transport into the cytosol via a lysosomal transporter. The molecular basis of the trypanocidal activity of suramin remains unclear, but some evidence suggests broad, but specific, impacts on trypanosome metabolism (i.e. polypharmacology). Here we observed that suramin is rapidly accumulated in trypanosome cells proportionally to ISG75 abundance. Although we found little evidence that suramin disrupts glycolytic or glycosomal pathways, we noted increased mitochondrial ATP production, but a net decrease in cellular ATP levels. Metabolomics highlighted additional impacts on mitochondrial metabolism, including partial Krebs' cycle activation and significant accumulation of pyruvate, corroborated by increased expression of mitochondrial enzymes and transporters. Significantly, the vast majority of suramin-induced proteins were normally more abundant in the insect forms compared with the blood stage of the parasite, including several proteins associated with differentiation. We conclude that suramin has multiple and complex effects on trypanosomes, but unexpectedly partially activates mitochondrial ATP-generating activity. We propose that despite apparent compensatory mechanisms in drug-challenged cells, the suramin-induced collapse of cellular ATP ultimately leads to trypanosome cell death.
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Affiliation(s)
- Martin Zoltner
- School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Gustavo D Campagnaro
- Institute for Infection, Immunity, and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Gergana Taleva
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Institute of Parasitology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Alana Burrell
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Michela Cerone
- Institute for Infection, Immunity, and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Ka-Fai Leung
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Fiona Achcar
- Wellcome Centre for Integrative Parasitology and Glasgow Polyomics, University of Glasgow, Glasgow, United Kingdom
| | - David Horn
- School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Sue Vaughan
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Catarina Gadelha
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Institute of Parasitology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Michael P Barrett
- Wellcome Centre for Integrative Parasitology and Glasgow Polyomics, University of Glasgow, Glasgow, United Kingdom
| | - Harry P de Koning
- Institute for Infection, Immunity, and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Mark C Field
- School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom .,Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Institute of Parasitology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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Pham KTM, Li Z. Regulated protein stabilization underpins the functional interplay among basal body components in Trypanosoma brucei. J Biol Chem 2020; 295:729-742. [PMID: 31819011 DOI: 10.1074/jbc.ra119.011352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/03/2019] [Indexed: 11/06/2022] Open
Abstract
The basal body in the human parasite Trypanosoma brucei is structurally equivalent to the centriole in animals and functions in the nucleation of axonemal microtubules in the flagellum. T. brucei lacks many evolutionarily conserved centriolar protein homologs and constructs the basal body through unknown mechanisms. Two evolutionarily conserved centriole/basal body cartwheel proteins, TbSAS-6 and TbBLD10, and a trypanosome-specific protein, BBP65, play essential roles in basal body biogenesis in T. brucei, but how they cooperate in the regulation of basal body assembly remains elusive. Here using RNAi, endogenous epitope tagging, immunofluorescence microscopy, and 3D-structured illumination super-resolution microscopy, we identified a new trypanosome-specific protein named BBP164 and found that it has an essential role in basal body biogenesis in T. brucei Further investigation of the functional interplay among BBP164 and the other three regulators of basal body assembly revealed that BBP164 and BBP65 are interdependent for maintaining their stability and depend on TbSAS-6 and TbBLD10 for their stabilization in the basal body. Additionally, TbSAS-6 and TbBLD10 are independent from each other and from BBP164 and BBP65 for maintaining their stability in the basal body. These findings demonstrate that basal body cartwheel proteins are required for stabilizing other basal body components and uncover that regulation of protein stability is an unusual control mechanism for assembly of the basal body in T. brucei.
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Affiliation(s)
- Kieu T M Pham
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Ziyin Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas 77030
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40
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Koeller CM, Tiengwe C, Schwartz KJ, Bangs JD. Steric constraints control processing of glycosylphosphatidylinositol anchors in Trypanosoma brucei. J Biol Chem 2020; 295:2227-2238. [PMID: 31932305 DOI: 10.1074/jbc.ra119.010847] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 12/26/2019] [Indexed: 11/06/2022] Open
Abstract
The transferrin receptor (TfR) of the bloodstream form (BSF) of Trypanosoma brucei is a heterodimer comprising glycosylphosphatidylinositol (GPI)-anchored expression site-associated gene 6 (ESAG6 or E6) and soluble ESAG7. Mature E6 has five N-glycans, consisting of three oligomannose and two unprocessed paucimannose structures. Its GPI anchor is modified by the addition of 4-6 α-galactose residues. TfR binds tomato lectin (TL), specific for N-acetyllactosamine (LacNAc) repeats, and previous studies have shown transport-dependent increases in E6 size consistent with post-glycan processing in the endoplasmic reticulum. Using pulse-chase radiolabeling, peptide-N-glycosidase F treatment, lectin pulldowns, and exoglycosidase treatment, we have now investigated TfR N-glycan and GPI processing. E6 increased ∼5 kDa during maturation, becoming reactive with both TL and Erythrina cristagalli lectin (ECL, terminal LacNAc), indicating synthesis of poly-LacNAc on paucimannose N-glycans. This processing was lost after exoglycosidase treatment and after RNAi-based silencing of TbSTT3A, the oligosaccharyltransferase that transfers paucimannose structures to nascent secretory polypeptides. These results contradict previous structural studies. Minor GPI processing was also observed, consistent with α-galactose addition. However, increasing the spacing between E6 protein and the GPI ω-site (aa 4-7) resulted in extensive post-translational processing of the GPI anchor to a form that was TL/ECL-reactive, suggesting the addition of LacNAc structures, confirmed by identical assays with BiPNHP, a non-N-glycosylated GPI-anchored reporter. We conclude that BSF trypanosomes can modify GPIs by generating structures reminiscent of those present in insect-stage trypanosomes and that steric constraints, not stage-specific expression of glycosyltransferases, regulate GPI processing.
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Affiliation(s)
- Carolina M Koeller
- Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York 14214
| | - Calvin Tiengwe
- Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York 14214
| | - Kevin J Schwartz
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, 53706
| | - James D Bangs
- Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York 14214.
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Lorès P, Dacheux D, Kherraf ZE, Nsota Mbango JF, Coutton C, Stouvenel L, Ialy-Radio C, Amiri-Yekta A, Whitfield M, Schmitt A, Cazin C, Givelet M, Ferreux L, Fourati Ben Mustapha S, Halouani L, Marrakchi O, Daneshipour A, El Khouri E, Do Cruzeiro M, Favier M, Guillonneau F, Chaudhry M, Sakheli Z, Wolf JP, Patrat C, Gacon G, Savinov SN, Hosseini SH, Robinson DR, Zouari R, Ziyyat A, Arnoult C, Dulioust E, Bonhivers M, Ray PF, Touré A. Mutations in TTC29, Encoding an Evolutionarily Conserved Axonemal Protein, Result in Asthenozoospermia and Male Infertility. Am J Hum Genet 2019; 105:1148-1167. [PMID: 31735292 DOI: 10.1016/j.ajhg.2019.10.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 10/11/2019] [Indexed: 12/30/2022] Open
Abstract
In humans, structural or functional defects of the sperm flagellum induce asthenozoospermia, which accounts for the main sperm defect encountered in infertile men. Herein we focused on morphological abnormalities of the sperm flagellum (MMAF), a phenotype also termed "short tails," which constitutes one of the most severe sperm morphological defects resulting in asthenozoospermia. In previous work based on whole-exome sequencing of a cohort of 167 MMAF-affected individuals, we identified bi-allelic loss-of-function mutations in more than 30% of the tested subjects. In this study, we further analyzed this cohort and identified five individuals with homozygous truncating variants in TTC29, a gene preferentially and highly expressed in the testis, and encoding a tetratricopeptide repeat-containing protein related to the intraflagellar transport (IFT). One individual carried a frameshift variant, another one carried a homozygous stop-gain variant, and three carried the same splicing variant affecting a consensus donor site. The deleterious effect of this last variant was confirmed on the corresponding transcript and protein product. In addition, we produced and analyzed TTC29 loss-of-function models in the flagellated protist T. brucei and in M. musculus. Both models confirmed the importance of TTC29 for flagellar beating. We showed that in T. brucei the TPR structural motifs, highly conserved between the studied orthologs, are critical for TTC29 axonemal localization and flagellar beating. Overall our work demonstrates that TTC29 is a conserved axonemal protein required for flagellar structure and beating and that TTC29 mutations are a cause of male sterility due to MMAF.
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Affiliation(s)
- Patrick Lorès
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Denis Dacheux
- Université de Bordeaux, Microbiologie Fondamentale et Pathogénicité, CNRS UMR 5234, Bordeaux, France; Institut Polytechnique de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR-CNRS 5234, 33000 Bordeaux, France
| | - Zine-Eddine Kherraf
- INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France; CHU de Grenoble, UM GI-DPI, Grenoble 38000, France
| | - Jean-Fabrice Nsota Mbango
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Charles Coutton
- INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France; CHU Grenoble Alpes, UM de Génétique Chromosomique, Grenoble, France
| | - Laurence Stouvenel
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Come Ialy-Radio
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Amir Amiri-Yekta
- Department of Genetics, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran
| | - Marjorie Whitfield
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Alain Schmitt
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Caroline Cazin
- INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France
| | - Maëlle Givelet
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Lucile Ferreux
- Laboratoire d'Histologie Embryologie - Biologie de la Reproduction - CECOS Groupe Hospitalier Universitaire Paris Centre, Assistance Publique-Hôpitaux de Paris, Paris 75014, France
| | - Selima Fourati Ben Mustapha
- Histologie Embryologie et Biologie de la Reproduction, Centre de Promotion des Sciences de la Reproduction, Polyclinique les Jasmins, Centre Urbain Nord, 1003 Tunis, Tunisia
| | - Lazhar Halouani
- Histologie Embryologie et Biologie de la Reproduction, Centre de Promotion des Sciences de la Reproduction, Polyclinique les Jasmins, Centre Urbain Nord, 1003 Tunis, Tunisia
| | - Ouafi Marrakchi
- Histologie Embryologie et Biologie de la Reproduction, Centre de Promotion des Sciences de la Reproduction, Polyclinique les Jasmins, Centre Urbain Nord, 1003 Tunis, Tunisia
| | - Abbas Daneshipour
- Department of Genetics, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran
| | - Elma El Khouri
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Marcio Do Cruzeiro
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Maryline Favier
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - François Guillonneau
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Marhaba Chaudhry
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Zeinab Sakheli
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Jean-Philippe Wolf
- INSERM U1016, Institut Cochin, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France; Laboratoire d'Histologie Embryologie - Biologie de la Reproduction - CECOS Groupe Hospitalier Universitaire Paris Centre, Assistance Publique-Hôpitaux de Paris, Paris 75014, France
| | - Catherine Patrat
- INSERM U1016, Institut Cochin, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France; Laboratoire d'Histologie Embryologie - Biologie de la Reproduction - CECOS Groupe Hospitalier Universitaire Paris Centre, Assistance Publique-Hôpitaux de Paris, Paris 75014, France
| | - Gérard Gacon
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Sergey N Savinov
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Seyedeh Hanieh Hosseini
- Department of Andrology, Reproductive Biomedicine Research Center, Royan Institutefor Reproductive Biomedicine, ACECR, Tehran, Iran
| | - Derrick R Robinson
- Université de Bordeaux, Microbiologie Fondamentale et Pathogénicité, CNRS UMR 5234, Bordeaux, France
| | - Raoudha Zouari
- Histologie Embryologie et Biologie de la Reproduction, Centre de Promotion des Sciences de la Reproduction, Polyclinique les Jasmins, Centre Urbain Nord, 1003 Tunis, Tunisia
| | - Ahmed Ziyyat
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France; Laboratoire d'Histologie Embryologie - Biologie de la Reproduction - CECOS Groupe Hospitalier Universitaire Paris Centre, Assistance Publique-Hôpitaux de Paris, Paris 75014, France
| | - Christophe Arnoult
- INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France
| | - Emmanuel Dulioust
- INSERM U1016, Institut Cochin, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France; Laboratoire d'Histologie Embryologie - Biologie de la Reproduction - CECOS Groupe Hospitalier Universitaire Paris Centre, Assistance Publique-Hôpitaux de Paris, Paris 75014, France
| | - Mélanie Bonhivers
- Université de Bordeaux, Microbiologie Fondamentale et Pathogénicité, CNRS UMR 5234, Bordeaux, France
| | - Pierre F Ray
- INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France; CHU de Grenoble, UM GI-DPI, Grenoble 38000, France
| | - Aminata Touré
- INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France.
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42
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Imhof S, Zhang J, Wang H, Bui KH, Nguyen H, Atanasov I, Hui WH, Yang SK, Zhou ZH, Hill KL. Cryo electron tomography with volta phase plate reveals novel structural foundations of the 96-nm axonemal repeat in the pathogen Trypanosoma brucei. eLife 2019; 8:e52058. [PMID: 31710293 PMCID: PMC6974359 DOI: 10.7554/elife.52058] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/11/2019] [Indexed: 12/12/2022] Open
Abstract
The 96-nm axonemal repeat includes dynein motors and accessory structures as the foundation for motility of eukaryotic flagella and cilia. However, high-resolution 3D axoneme structures are unavailable for organisms among the Excavates, which include pathogens of medical and economic importance. Here we report cryo electron tomography structures of the 96-nm repeat from Trypanosoma brucei, a protozoan parasite in the Excavate lineage that causes African trypanosomiasis. We examined bloodstream and procyclic life cycle stages, and a knockdown lacking DRC11/CMF22 of the nexin dynein regulatory complex (NDRC). Sub-tomogram averaging yields a resolution of 21.8 Å for the 96-nm repeat. We discovered several lineage-specific structures, including novel inter-doublet linkages and microtubule inner proteins (MIPs). We establish that DRC11/CMF22 is required for the NDRC proximal lobe that binds the adjacent doublet microtubule. We propose that lineage-specific elaboration of axoneme structure in T. brucei reflects adaptations to support unique motility needs in diverse host environments.
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Affiliation(s)
- Simon Imhof
- Department of Microbiology, Immunology and Molecular GeneticsUniversity of California, Los AngelesLos AngelesUnited States
| | - Jiayan Zhang
- Department of Microbiology, Immunology and Molecular GeneticsUniversity of California, Los AngelesLos AngelesUnited States
- Molecular Biology InstituteUniversity of California, Los AngelesLos AngelesUnited States
- California NanoSystems InstituteUniversity of California, Los AngelesLos AngelesUnited States
| | - Hui Wang
- Department of Microbiology, Immunology and Molecular GeneticsUniversity of California, Los AngelesLos AngelesUnited States
- California NanoSystems InstituteUniversity of California, Los AngelesLos AngelesUnited States
- Department of BioengineeringUniversity of California, Los AngelesLos AngelesUnited States
| | - Khanh Huy Bui
- Department of Anatomy and Cell BiologyMcGill UniversityMontrealUnited States
| | - Hoangkim Nguyen
- Department of Microbiology, Immunology and Molecular GeneticsUniversity of California, Los AngelesLos AngelesUnited States
| | - Ivo Atanasov
- California NanoSystems InstituteUniversity of California, Los AngelesLos AngelesUnited States
| | - Wong H Hui
- California NanoSystems InstituteUniversity of California, Los AngelesLos AngelesUnited States
| | - Shun Kai Yang
- Department of Anatomy and Cell BiologyMcGill UniversityMontrealUnited States
| | - Z Hong Zhou
- Department of Microbiology, Immunology and Molecular GeneticsUniversity of California, Los AngelesLos AngelesUnited States
- Molecular Biology InstituteUniversity of California, Los AngelesLos AngelesUnited States
- California NanoSystems InstituteUniversity of California, Los AngelesLos AngelesUnited States
- Department of BioengineeringUniversity of California, Los AngelesLos AngelesUnited States
| | - Kent L Hill
- Department of Microbiology, Immunology and Molecular GeneticsUniversity of California, Los AngelesLos AngelesUnited States
- Molecular Biology InstituteUniversity of California, Los AngelesLos AngelesUnited States
- California NanoSystems InstituteUniversity of California, Los AngelesLos AngelesUnited States
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43
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Soulette CM, Oliverio O, Roy SW. On the Function of Trans-Splicing: No Evidence for Widespread Proteome Diversification in Trypanosomes. Genome Biol Evol 2019; 11:3014-3021. [PMID: 31599940 PMCID: PMC6821157 DOI: 10.1093/gbe/evz217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2019] [Indexed: 11/24/2022] Open
Abstract
A long-standing mystery of genomic/transcriptomic structure involves spliced leader trans-splicing (SLTS), in which short RNA “tags” transcribed from a distinct genomic locus is added near the 5′ end of RNA transcripts by the spliceosome. SLTS has been observed in diverse eukaryotes in a phylogenetic pattern implying recurrent independent evolution. This striking convergence suggests important functions for SLTS, however no general novel function is known. Recent findings of frequent alternative SLTS (ALT-TS) suggest that ALT-TS could impart widespread functionality. Here, we tested the hypothesis that ALT-TS diversifies proteomes by comparing splicing patterns in orthologous genes between two deeply diverged trypanosome parasites. We also tested proteome diversification functions of ALT-TS by utilizing ribosome profiling sequence data. Finally, we investigated ALT-TS as a mechanism to regulate the expression of unproductive transcripts. Although our results indicate the functional importance of some cases of trans-splicing, we find no evidence for the hypothesis that proteome diversification is a general function of trans-splicing.
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Affiliation(s)
- Cameron M Soulette
- Department of Biology, San Francisco State University.,Molecular, Cellular & Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA
| | | | - Scott W Roy
- Department of Biology, San Francisco State University.,Quantitative Systems Biology, University of California, Merced
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44
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Davis JK, Aguirre LA, Barber NA, Stevenson PC, Adler LS. From plant fungi to bee parasites: mycorrhizae and soil nutrients shape floral chemistry and bee pathogens. Ecology 2019; 100:e02801. [PMID: 31234229 PMCID: PMC6773465 DOI: 10.1002/ecy.2801] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 04/16/2019] [Accepted: 05/28/2019] [Indexed: 12/19/2022]
Abstract
Bee populations have experienced declines in recent years, due in part to increased disease incidence. Multiple factors influence bee-pathogen interactions, including nectar and pollen quality and secondary metabolites. However, we lack an understanding of how plant interactions with their environment shape bee diet quality. We examined how plant interactions with the belowground environment alter floral rewards and, in turn, bee-pathogen interactions. Soil-dwelling mycorrhizal fungi are considered plant mutualists, although the outcome of the relationship depends on environmental conditions such as nutrients. In a 2 × 2 factorial design, we asked whether mycorrhizal fungi and nutrients affect concentrations of nectar and pollen alkaloids (anabasine and nicotine) previously shown to reduce infection by the gut pathogen Crithidia in the native bumble bee Bombus impatiens. To ask how plant interactions affect this common bee pathogen, we fed pollen and nectar from our treatment plants, and from a wildflower pollen control with artificial nectar, to bees infected with Crithidia. Mycorrhizal fungi and fertilizer both influenced flowering phenology and floral chemistry. While we found no anabasine or nicotine in nectar, high fertilizer increased anabasine and nicotine in pollen. Arbuscular mycorrhizal fungi (AMF) decreased nicotine concentrations, but the reduction due to AMF was stronger in high than low-nutrient conditions. AMF and nutrients also had interactive effects on bee pathogens via changes in nectar and pollen. High fertilizer reduced Crithidia cell counts relative to low fertilizer in AMF plants, but increased Crithidia in non-AMF plants. These results did not correspond with effects of fertilizer and AMF on pollen alkaloid concentrations, suggesting that other components of pollen or nectar were affected by treatments and shaped pathogen counts. Our results indicate that soil biotic and abiotic environment can alter bee-pathogen interactions via changes in floral rewards, and underscore the importance of integrative studies to predict disease dynamics and ecological outcomes.
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Affiliation(s)
- Julie K. Davis
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA
- Department of Entomology, Cornell University, Ithaca, NY 14850, USA
| | - Luis A. Aguirre
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Nicholas A. Barber
- Department of Biological Sciences, San Diego State University, San Diego, CA 92182, USA
| | - Philip C. Stevenson
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Surrey TW9 3AB, UK
- Natural Resources Institute, University of Greenwich, Chatham, Kent ME4 4TB, UK
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
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45
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Lannon H, Shah SS, Dias L, Blackler D, Alper SL, Pollak MR, Friedman DJ. Apolipoprotein L1 (APOL1) risk variant toxicity depends on the haplotype background. Kidney Int 2019; 96:1303-1307. [PMID: 31611067 DOI: 10.1016/j.kint.2019.07.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 06/27/2019] [Accepted: 07/03/2019] [Indexed: 01/01/2023]
Abstract
The Apolipoprotein L1 (APOL1) risk variants G1 and G2 are associated with high rates of kidney disease in African Americans in genetic studies. However, our understanding of APOL1 biology has lagged far behind. Here we report that engineering G1 and G2 mutations on unnatural haplotype backgrounds instead of on the specific G1 and G2 haplotype backgrounds that occur in nature profoundly alters APOL1-mediated cytotoxicity in experimental systems. Thus, in addition to helping resolve some important controversies in the APOL1 field, our demonstration of the critical influence of haplotype background may apply more generally to the study of other genetic variants that cause or predispose to human disease.
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Affiliation(s)
- Herbert Lannon
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Shrijal S Shah
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Leny Dias
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Daniel Blackler
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Seth L Alper
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Martin R Pollak
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - David J Friedman
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
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46
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Szöőr B, Simon DV, Rojas F, Young J, Robinson DR, Krüger T, Engstler M, Matthews KR. Positional Dynamics and Glycosomal Recruitment of Developmental Regulators during Trypanosome Differentiation. mBio 2019; 10:e00875-19. [PMID: 31289175 DOI: 10.1128/mBio.00875-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
African trypanosomes are parasites of sub-Saharan Africa responsible for both human and animal disease. The parasites are transmitted by tsetse flies, and completion of their life cycle involves progression through several development steps. The initiation of differentiation between blood and tsetse fly forms is signaled by a phosphatase cascade, ultimately trafficked into peroxisome-related organelles called glycosomes that are unique to this group of organisms. Glycosomes undergo substantial remodeling of their composition and function during the differentiation step, but how this is regulated is not understood. Here we identify a cytological site where the signaling molecules controlling differentiation converge before the dispersal of one of them into glycosomes. In combination, the study provides the first insight into the spatial coordination of signaling pathway components in trypanosomes as they undergo cell-type differentiation. Glycosomes are peroxisome-related organelles that compartmentalize the glycolytic enzymes in kinetoplastid parasites. These organelles are developmentally regulated in their number and composition, allowing metabolic adaptation to the parasite’s needs in the blood of mammalian hosts or within their arthropod vector. A protein phosphatase cascade regulates differentiation between parasite developmental forms, comprising a tyrosine phosphatase, Trypanosoma brucei PTP1 (TbPTP1), which dephosphorylates and inhibits a serine threonine phosphatase, TbPIP39, which promotes differentiation. When TbPTP1 is inactivated, TbPIP39 is activated and during differentiation becomes located in glycosomes. Here we have tracked TbPIP39 recruitment to glycosomes during differentiation from bloodstream “stumpy” forms to procyclic forms. Detailed microscopy and live-cell imaging during the synchronous transition between life cycle stages revealed that in stumpy forms, TbPIP39 is located at a periflagellar pocket site closely associated with TbVAP, which defines the flagellar pocket endoplasmic reticulum. TbPTP1 is also located at the same site in stumpy forms, as is REG9.1, a regulator of stumpy-enriched mRNAs. This site provides a molecular node for the interaction between TbPTP1 and TbPIP39. Within 30 min of the initiation of differentiation, TbPIP39 relocates to glycosomes, whereas TbPTP1 disperses to the cytosol. Overall, the study identifies a “stumpy regulatory nexus” (STuRN) that coordinates the molecular components of life cycle signaling and glycosomal development during transmission of Trypanosoma brucei.
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47
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Abstract
Parasites elicit several physiological changes in their host to enhance transmission. Little is known about the functional association between parasitism and microbiota-provisioned resources typically dedicated to animal hosts and how these goods may be rerouted to optimize parasite development. This study is the first to identify a specific symbiont-generated metabolite that impacts insect vector competence by facilitating parasite establishment and, thus, eventual transmission. Specifically, we demonstrate that the tsetse fly obligate mutualist Wigglesworthia provisions folate (vitamin B9) that pathogenic African trypanosomes exploit in an effort to successfully establish an infection in the vector’s MG. This process is essential for the parasite to complete its life cycle and be transmitted to a new vertebrate host. Disrupting metabolic contributions provided by the microbiota of arthropod disease vectors may fuel future innovative control strategies while also offering minimal nontarget effects. Many symbionts supplement their host’s diet with essential nutrients. However, whether these nutrients also enhance parasitism is unknown. In this study, we investigated whether folate (vitamin B9) production by the tsetse fly (Glossina spp.) essential mutualist, Wigglesworthia, aids auxotrophic African trypanosomes in completing their life cycle within this obligate vector. We show that the expression of Wigglesworthia folate biosynthesis genes changes with the progression of trypanosome infection within tsetse. The disruption of Wigglesworthia folate production caused a reduction in the percentage of flies that housed midgut (MG) trypanosome infections. However, decreased folate did not prevent MG trypanosomes from migrating to and establishing an infection in the fly’s salivary glands, thus suggesting that nutrient requirements vary throughout the trypanosome life cycle. We further substantiated that trypanosomes rely on symbiont-generated folate by feeding this vitamin to Glossina brevipalpis, which exhibits low trypanosome vector competency and houses Wigglesworthia incapable of producing folate. Folate-supplemented G. brevipalpis flies were significantly more susceptible to trypanosome infection, further demonstrating that this vitamin facilitates parasite infection establishment. Our cumulative results provide evidence that Wigglesworthia provides a key metabolite (folate) that is “hijacked” by trypanosomes to enhance their infectivity, thus indirectly impacting tsetse species vector competency. Parasite dependence on symbiont-derived micronutrients, which likely also occurs in other arthropod vectors, represents a relationship that may be exploited to reduce disease transmission.
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48
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Sabalette KB, Romaniuk MA, Noé G, Cassola A, Campo VA, De Gaudenzi JG. The RNA-binding protein TcUBP1 up-regulates an RNA regulon for a cell surface-associated Trypanosoma cruzi glycoprotein and promotes parasite infectivity. J Biol Chem 2019; 294:10349-10364. [PMID: 31113862 DOI: 10.1074/jbc.ra118.007123] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 05/06/2019] [Indexed: 11/06/2022] Open
Abstract
The regulation of transcription in trypanosomes is unusual. To modulate protein synthesis during their complex developmental stages, these unicellular microorganisms rely largely on post-transcriptional gene expression pathways. These pathways include a plethora of RNA-binding proteins (RBPs) that modulate all steps of the mRNA life cycle in trypanosomes and help organize transcriptomes into clusters of post-transcriptional regulons. The aim of this work was to characterize an RNA regulon comprising numerous transcripts of trypomastigote-associated cell-surface glycoproteins that are preferentially expressed in the infective stages of the human parasite Trypanosoma cruzi. In vitro and in vivo RNA-binding assays disclosed that these glycoprotein mRNAs are targeted by the small trypanosomatid-exclusive RBP in T. cruzi, U-rich RBP 1 (TcUBP1). Overexpression of a GFP-tagged TcUBP1 in replicative parasites resulted in >10 times up-regulated expression of transcripts encoding surface proteins and in changes in their subcellular localization from the posterior region to the perinuclear region of the cytoplasm, as is typically observed in the infective parasite stages. Moreover, RT-quantitative PCR analysis of actively translated mRNAs by sucrose cushion fractionation revealed an increased abundance of these target transcripts in the polysome fraction of TcUBP1-induced samples. Because these surface proteins are involved in cell adherence or invasion during host infection, we also carried out in vitro infections with TcUBP1-transgenic trypomastigotes and observed that TcUBP1 overexpression significantly increases parasite infectivity. Our findings provide evidence for a role of TcUBP1 in trypomastigote stage-specific gene regulation important for T. cruzi virulence.
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Affiliation(s)
- Karina B Sabalette
- From the Instituto de Investigaciones Biotecnológicas, UNSAM-CONICET, 1650 San Martín, Buenos Aires, Argentina
| | - María Albertina Romaniuk
- From the Instituto de Investigaciones Biotecnológicas, UNSAM-CONICET, 1650 San Martín, Buenos Aires, Argentina
| | - Griselda Noé
- From the Instituto de Investigaciones Biotecnológicas, UNSAM-CONICET, 1650 San Martín, Buenos Aires, Argentina
| | - Alejandro Cassola
- From the Instituto de Investigaciones Biotecnológicas, UNSAM-CONICET, 1650 San Martín, Buenos Aires, Argentina
| | - Vanina A Campo
- From the Instituto de Investigaciones Biotecnológicas, UNSAM-CONICET, 1650 San Martín, Buenos Aires, Argentina
| | - Javier G De Gaudenzi
- From the Instituto de Investigaciones Biotecnológicas, UNSAM-CONICET, 1650 San Martín, Buenos Aires, Argentina
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49
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DeLorenzo M, Carias E, Mustonen A, Gonzalez O, Dick EJ, Kumar S. In situ hybridization assay for the diagnosis of chagas myocarditis and orchitis in a rhesus macaque (Macaca mulatta): A case report. J Med Primatol 2019; 48:182-185. [PMID: 30912150 DOI: 10.1111/jmp.12406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 01/09/2018] [Accepted: 02/25/2019] [Indexed: 11/29/2022]
Abstract
We present the first documented case of Trypanosoma cruzi-induced orchitis in a rhesus macaque. Additionally, we describe an in situ hybridization-based assay to confirm T. cruzi infection in formalin-fixed tissues.
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Affiliation(s)
- Megan DeLorenzo
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas.,College of Agriculture Forestry and Life Sciences, Clemson University, Clemson, South Carolina
| | - Elvira Carias
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas.,Microbiology and Immunology Program, University of Texas at San Antonio, San Antonio, Texas
| | - Allison Mustonen
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas
| | - Olga Gonzalez
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas
| | - Edward J Dick
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas
| | - Shyamesh Kumar
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas
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50
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Mensa-Wilmot K, Hoffman B, Wiedeman J, Sullenberger C, Sharma A. Kinetoplast Division Factors in a Trypanosome. Trends Parasitol 2019; 35:119-128. [PMID: 30638954 DOI: 10.1016/j.pt.2018.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/06/2018] [Accepted: 11/11/2018] [Indexed: 02/08/2023]
Abstract
Inheritance of the single mitochondrial nucleoid (kinetoplast) in the trypanosome requires numerous proteins, many of whose precise roles are unclear. By considering kinetoplast DNA (kDNA) as a template for cleavage into two equal-size networks, we predicted sets of mutant kinetoplasts associated with defects in each of the five steps in the kinetoplast cycle. Comparison of these kinetoplasts with those obtained after gene knockdowns enabled assignment of proteins to five classes - kDNA synthesis, site of scission selection, scission, separation, and partitioning. These studies highlight how analysis of mutant kinetoplast phenotypes may be used to predict functional categories of proteins involved in the biogenesis of kinetoplasts.
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Affiliation(s)
- Kojo Mensa-Wilmot
- Department of Cellular Biology, 724 Biological Sciences Building, University of Georgia, Athens, Georgia 30602, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia 30602, USA.
| | - Benjamin Hoffman
- Department of Cellular Biology, 724 Biological Sciences Building, University of Georgia, Athens, Georgia 30602, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia 30602, USA
| | - Justin Wiedeman
- Department of Cellular Biology, 724 Biological Sciences Building, University of Georgia, Athens, Georgia 30602, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia 30602, USA
| | - Catherine Sullenberger
- Department of Cellular Biology, 724 Biological Sciences Building, University of Georgia, Athens, Georgia 30602, USA
| | - Amrita Sharma
- Department of Cellular Biology, 724 Biological Sciences Building, University of Georgia, Athens, Georgia 30602, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia 30602, USA
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