1
|
Serra L, Silva Pereira S, Viegas IJ, Machado H, López-Escobar L, Figueiredo LM. m 6A landscape is more pervasive when Trypanosoma brucei exits the cell cycle. Biomed J 2024:100728. [PMID: 38641210 DOI: 10.1016/j.bj.2024.100728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/11/2024] [Accepted: 04/11/2024] [Indexed: 04/21/2024] Open
Abstract
N6-methyladenosine (m6A) is a mRNA modification with important roles in gene expression. In African trypanosomes, this post-transcriptional modification is detected in hundreds of transcripts and it affects the stability of the variant surface glycoprotein (VSG) transcript in the proliferating blood stream form. However, how the m6A landscape varies across the life cycle remains poorly defined. Using full-length, non-fragmented RNA, we immunoprecipitated and sequenced m6A-modified transcripts across three life cycle stages of Trypanosoma brucei - slender (proliferative), stumpy (quiescent), and procyclic forms (proliferative). We found that 1037 transcripts are methylated in at least one of these three life cycle stages. While 21% of methylated transcripts are common in the three stages of the life cycle, globally each stage has a distinct methylome. Interestingly, 47% of methylated transcripts are detected in the quiescent stumpy form only, suggesting a critical role for m6A when parasites exit the cell cycle and prepare for transmission by the Tsetse fly. In this stage, we found that a significant proportion of methylated transcripts encodes for proteins involved in RNA metabolism, which is consistent with their reduced transcription and translation. Moreover, we found that not all major surface proteins are regulated by m6A, as procyclins are not methylated, and that, within the VSG repertoire, not all VSG transcripts are demethylated upon parasite differentiation to procyclic form. This study reveals that the m6A regulatory landscape is specific to each life cycle stage, becoming more pervasive as T. brucei exits the cell cycle.
Collapse
Affiliation(s)
- Lúcia Serra
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa
| | - Sara Silva Pereira
- Católica Biomedical Research Centre, Católica Medical School, Universidade Católica Portuguesa
| | - Idálio J Viegas
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa; Current affiliation: Institute of Inflammation and Ageing, University of Birmingham
| | - Henrique Machado
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa
| | - Lara López-Escobar
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa.
| |
Collapse
|
2
|
Iribarren PA, Di Marzio LA, Berazategui MA, Saura A, Coria L, Cassataro J, Rojas F, Navarro M, Alvarez VE. Depolymerization of SUMO chains induces slender to stumpy differentiation in T. brucei bloodstream parasites. PLoS Pathog 2024; 20:e1012166. [PMID: 38635823 PMCID: PMC11060531 DOI: 10.1371/journal.ppat.1012166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/30/2024] [Accepted: 04/01/2024] [Indexed: 04/20/2024] Open
Abstract
Trypanosoma brucei are protozoan parasites that cause sleeping sickness in humans and nagana in cattle. Inside the mammalian host, a quorum sensing-like mechanism coordinates its differentiation from a slender replicative form into a quiescent stumpy form, limiting growth and activating metabolic pathways that are beneficial to the parasite in the insect host. The post-translational modification of proteins with the Small Ubiquitin-like MOdifier (SUMO) enables dynamic regulation of cellular metabolism. SUMO can be conjugated to its targets as a monomer but can also form oligomeric chains. Here, we have investigated the role of SUMO chains in T. brucei by abolishing the ability of SUMO to polymerize. We have found that parasites able to conjugate only SUMO monomers are primed for differentiation. This was demonstrated for monomorphic lines that are normally unable to produce stumpy forms in response to quorum sensing signaling in mice, and also for pleomorphic cell lines in which stumpy cells were observed at unusually low parasitemia levels. SUMO chain mutants showed a stumpy compatible transcriptional profile and better competence to differentiate into procyclics. Our study indicates that SUMO depolymerization may represent a coordinated signal triggered during stumpy activation program.
Collapse
Affiliation(s)
- Paula Ana Iribarren
- Instituto de Investigaciones Biotecnológicas “Dr. Rodolfo Ugalde”–IIBIO (UNSAM-CONICET), San Martin, Buenos Aires, Argentina
| | - Lucía Ayelén Di Marzio
- Instituto de Investigaciones Biotecnológicas “Dr. Rodolfo Ugalde”–IIBIO (UNSAM-CONICET), San Martin, Buenos Aires, Argentina
| | - María Agustina Berazategui
- Instituto de Investigaciones Biotecnológicas “Dr. Rodolfo Ugalde”–IIBIO (UNSAM-CONICET), San Martin, Buenos Aires, Argentina
| | - Andreu Saura
- Instituto de Parasitología y Biomedicina “López-Neyra”, CSIC (IPBLN-CSIC), Granada, Spain
| | - Lorena Coria
- Instituto de Investigaciones Biotecnológicas “Dr. Rodolfo Ugalde”–IIBIO (UNSAM-CONICET), San Martin, Buenos Aires, Argentina
| | - Juliana Cassataro
- Instituto de Investigaciones Biotecnológicas “Dr. Rodolfo Ugalde”–IIBIO (UNSAM-CONICET), San Martin, Buenos Aires, Argentina
| | - Federico Rojas
- Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, United Kingdom
| | - Miguel Navarro
- Instituto de Parasitología y Biomedicina “López-Neyra”, CSIC (IPBLN-CSIC), Granada, Spain
| | - Vanina Eder Alvarez
- Instituto de Investigaciones Biotecnológicas “Dr. Rodolfo Ugalde”–IIBIO (UNSAM-CONICET), San Martin, Buenos Aires, Argentina
| |
Collapse
|
3
|
Calvo-Alvarez E, Ngoune JMT, Sharma P, Cooper A, Camara A, Travaillé C, Crouzols A, MacLeod A, Rotureau B. FLAgellum Member 8 modulates extravascular distribution of African trypanosomes. PLoS Pathog 2023; 19:e1011220. [PMID: 38127941 PMCID: PMC10769064 DOI: 10.1371/journal.ppat.1011220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 01/05/2024] [Accepted: 12/06/2023] [Indexed: 12/23/2023] Open
Abstract
In the mammalian host, the biology of tissue-dwelling Trypanosoma brucei parasites is not completely understood, especially the mechanisms involved in their extravascular colonization. The trypanosome flagellum is an essential organelle in multiple aspects of the parasites' development. The flagellar protein termed FLAgellar Member 8 (FLAM8) acts as a docking platform for a pool of cyclic AMP response protein 3 (CARP3) that is involved in signaling. FLAM8 exhibits a stage-specific distribution suggesting specific functions in the mammalian and vector stages of the parasite. Analyses of knockdown and knockout trypanosomes in their mammalian forms demonstrated that FLAM8 is not essential in vitro for survival, growth, motility and stumpy differentiation. Functional investigations in experimental infections showed that FLAM8-deprived trypanosomes can establish and maintain an infection in the blood circulation and differentiate into insect transmissible forms. However, quantitative bioluminescence imaging and gene expression analysis revealed that FLAM8-null parasites exhibit a significantly impaired dissemination in the extravascular compartment, that is restored by the addition of a single rescue copy of FLAM8. In vitro trans-endothelial migration assays revealed significant defects in trypanosomes lacking FLAM8. FLAM8 is the first flagellar component shown to modulate T. brucei distribution in the host tissues, possibly through sensing functions, contributing to the maintenance of extravascular parasite populations in mammalian anatomical niches, especially in the skin.
Collapse
Affiliation(s)
- Estefanía Calvo-Alvarez
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur, Université Paris Cité, Paris, France
| | - Jean Marc Tsagmo Ngoune
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur, Université Paris Cité, Paris, France
| | - Parul Sharma
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur, Université Paris Cité, Paris, France
- Sorbonne Université, ED515 Complexité du Vivant, Paris, France
| | - Anneli Cooper
- Wellcome Centre for Integrative Parasitology, College of Medical, Veterinary, and Life Sciences, Henry Wellcome Building for Comparative Medical Sciences, Glasgow, Scotland, United Kingdom
| | - Aïssata Camara
- Parasitology Unit, Institut Pasteur of Guinea, Conakry, Guinea
| | - Christelle Travaillé
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur, Université Paris Cité, Paris, France
- Photonic BioImaging (UTechS PBI), Institut Pasteur, Université Paris Cité, Paris, France
| | - Aline Crouzols
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur, Université Paris Cité, Paris, France
| | - Annette MacLeod
- Wellcome Centre for Integrative Parasitology, College of Medical, Veterinary, and Life Sciences, Henry Wellcome Building for Comparative Medical Sciences, Glasgow, Scotland, United Kingdom
| | - Brice Rotureau
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur, Université Paris Cité, Paris, France
- Parasitology Unit, Institut Pasteur of Guinea, Conakry, Guinea
| |
Collapse
|
4
|
Obi CF, Okpala MI, Anyogu DC, Onyeabor A, Ezeh IO, Ezeokonkwo RC. Comparative pathogenicity of drug-resistant and drug-sensitive Trypanosoma brucei and Trypanosoma congolense infections in Nigerian local dogs. Parasitol Res 2023; 122:49-60. [PMID: 36251088 DOI: 10.1007/s00436-022-07688-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 10/04/2022] [Indexed: 01/12/2023]
Abstract
Animal trypanosomosis is an important endemic and wasting disease in sub-Saharan Africa. Its control relies on chemotherapy, and resistance to trypanocides has been widely reported. The pathogenicity of drug-resistant canine trypanosomes is not clear with scanty information available. Thus, this study assessed the comparative pathogenicity of drug-resistant and drug-sensitive Trypanosoma brucei and Trypanosoma congolense infections in dogs. Twenty Nigerian local dogs were used and were randomly assigned into five groups (A-E) of four dogs each. Group A served as the uninfected-control group, while groups B and C were infected with 106 drug-sensitive T. congolense and T. brucei. Groups D and E were infected with 106 multidrug-resistant T. congolense and T. brucei, respectively. The pre-patent period (PPP), clinical signs, level of parasitaemia (LOP), rectal temperature, body weight, packed cell volume (PCV), red blood cell count (RBC), haemoglobin concentration (HbC), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), total leucocyte count (TLC) and survivability were assessed. Groups D and E had longer (p < 0.05) mean PPP than groups B and C. Also, group E dogs had lower (p < 0.05) mean LOP, longer (p < 0.05) mean survivability, and higher (p < 0.05) mean body weight, PCV, HbC and RBC than group C dogs. The clinical signs were very severe in group C dogs, compared to group E dogs. However, these parameters did not differ statistically between groups B and D. Thus, multidrug-resistant T. brucei was of lower pathogenicity than drug-sensitive T. brucei, while multidrug-resistant and drug-sensitive T. congolense had comparable pathogenicity following infection in dogs.
Collapse
Affiliation(s)
- Chukwunonso F Obi
- Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria.
| | - Michael I Okpala
- Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria
| | - Davinson C Anyogu
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria
| | - Amaechi Onyeabor
- Department of Veterinary Parasitology and Entomology, College of Veterinary Medicine, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria
| | - Ikenna O Ezeh
- Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria
| | - Romanus C Ezeokonkwo
- Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria
| |
Collapse
|
5
|
Slow growing behavior in African trypanosomes during adipose tissue colonization. Nat Commun 2022; 13:7548. [PMID: 36481558 PMCID: PMC9732351 DOI: 10.1038/s41467-022-34622-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 11/01/2022] [Indexed: 12/13/2022] Open
Abstract
When Trypanosoma brucei parasites, the causative agent of sleeping sickness, colonize the adipose tissue, they rewire gene expression. Whether this adaptation affects population behavior and disease treatment remained unknown. By using a mathematical model, we estimate that the population of adipose tissue forms (ATFs) proliferates slower than blood parasites. Analysis of the ATFs proteome, measurement of protein synthesis and proliferation rates confirm that the ATFs divide on average every 12 h, instead of 6 h in the blood. Importantly, the population of ATFs is heterogeneous with parasites doubling times ranging between 5 h and 35 h. Slow-proliferating parasites remain capable of reverting to the fast proliferation profile in blood conditions. Intravital imaging shows that ATFs are refractory to drug treatment. We propose that in adipose tissue, a subpopulation of T. brucei parasites acquire a slow growing behavior, which contributes to disease chronicity and treatment failure.
Collapse
|
6
|
Cai XL, Li SJ, Zhang P, Li Z, Hide G, Lai DH, Lun ZR. The Occurrence of Malignancy in Trypanosoma brucei brucei by Rapid Passage in Mice. Front Microbiol 2022; 12:806626. [PMID: 35087505 PMCID: PMC8789148 DOI: 10.3389/fmicb.2021.806626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/17/2021] [Indexed: 11/15/2022] Open
Abstract
Pleomorphic Trypanosoma brucei are best known for their tightly controlled cell growth and developmental program, which ensures their transmissibility and host fitness between the mammalian host and insect vector. However, after long-term adaptation in the laboratory or by natural evolution, monomorphic parasites can be derived. The origin of these monomorphic forms is currently unclear. Here, we produced a series of monomorphic trypanosome stocks by artificially syringe-passage in mice, creating snapshots of the transition from pleomorphism to monomorphism. We then compared these artificial monomorphic trypanosomes, alongside several naturally monomorphic T. evansi and T. equiperdum strains, with the pleomorphic T. brucei. In addition to failing to generate stumpy forms in animal bloodstream, we found that monomorphic trypanosomes from laboratory and nature exhibited distinct differentiation patterns, which are reflected by their distinct differentiation potential and transcriptional changes. Lab-adapted monomorphic trypanosomes could still be induced to differentiate, and showed only minor transcriptional differences to that of the pleomorphic slender forms but some accumulated differences were observed as the passages progress. All naturally monomorphic strains completely fail to differentiate, corresponding to their impaired differentiation regulation. We propose that the natural phenomenon of trypanosomal monomorphism is actually a malignant manifestation of protozoal cells. From a disease epidemiological and evolutionary perspective, our results provide evidence for a new way of thinking about the origin of these naturally monomorphic strains, the malignant evolution of trypanosomes may raise some concerns. Additionally, these monomorphic trypanosomes may reflect the quantitative and qualitative changes in the malignant evolution of T. brucei, suggesting that single-celled protozoa may also provide the most primitive model of cellular malignancy, which could be a primitive and inherent biological phenomenon of eukaryotic organisms from protozoans to mammals.
Collapse
Affiliation(s)
- Xiao-Li Cai
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Su-Jin Li
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Peng Zhang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Ziyin Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Geoff Hide
- Biomedical Research Centre, School of Science, Engineering and Environment, University of Salford, Salford, United Kingdom
| | - De-Hua Lai
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhao-Rong Lun
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| |
Collapse
|
7
|
Abstract
African trypanosomes are responsible for important diseases of humans and animals in sub-Saharan Africa. The best-studied species is Trypanosoma brucei, which is characterized by development in the mammalian host between morphologically slender and stumpy forms. The latter are adapted for transmission by the parasite's vector, the tsetse fly. The development of stumpy forms is driven by density-dependent quorum-sensing (QS), the molecular basis for which is now coming to light. In this review, I discuss the historical context and biological features of trypanosome QS and how it contributes to the parasite's infection dynamics within its mammalian host. Also, I discuss how QS can be lost in different trypanosome species, such as T. brucei evansi and T. brucei equiperdum, or modulated when parasites find themselves competing with others of different genotypes or of different trypanosome species in the same host. Finally, I consider the potential to exploit trypanosome QS therapeutically. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Keith R Matthews
- Institute for Immunology and Infection Research, Ashworth Laboratories, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom;
| |
Collapse
|
8
|
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] [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.
Collapse
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
| |
Collapse
|
9
|
Calvo-Álvarez E, Bonnefoy S, Salles A, Benson FE, McKean PG, Bastin P, Rotureau B. Redistribution of FLAgellar Member 8 during the trypanosome life cycle: Consequences for cell fate prediction. Cell Microbiol 2021; 23:e13347. [PMID: 33896083 PMCID: PMC8459223 DOI: 10.1111/cmi.13347] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/17/2021] [Accepted: 04/22/2021] [Indexed: 11/28/2022]
Abstract
The single flagellum of African trypanosomes is essential in multiple aspects of the parasites' development. The FLAgellar Member 8 protein (FLAM8), localised to the tip of the flagellum in cultured insect forms of Trypanosoma brucei, was identified as a marker of the locking event that controls flagellum length. Here, we investigated whether FLAM8 could also reflect the flagellum maturation state in other parasite cycle stages. We observed that FLAM8 distribution extended along the entire flagellar cytoskeleton in mammalian‐infective forms. Then, a rapid FLAM8 concentration to the distal tip occurs during differentiation into early insect forms, illustrating the remodelling of an existing flagellum. In the tsetse cardia, FLAM8 further localises to the entire length of the new flagellum during an asymmetric division. Strikingly, in parasites dividing in the tsetse midgut and in the salivary glands, the amount and distribution of FLAM8 in the new flagellum were seen to predict the daughter cell fate. We propose and discuss how FLAM8 could be considered a meta‐marker of the flagellum stage and maturation state in trypanosomes.
Collapse
Affiliation(s)
- Estefanía Calvo-Álvarez
- Trypanosome Cell Biology Unit, Institut Pasteur and INSERM U1201, Paris, France.,Trypanosome Transmission Group, Institut Pasteur, Paris, France
| | - Serge Bonnefoy
- Trypanosome Cell Biology Unit, Institut Pasteur and INSERM U1201, Paris, France
| | - Audrey Salles
- Unit of Technology and Service Photonic BioImaging (UTechS PBI), C2RT, Institut Pasteur, Paris, France
| | - Fiona E Benson
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, UK
| | - Paul G McKean
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, UK
| | - Philippe Bastin
- Trypanosome Cell Biology Unit, Institut Pasteur and INSERM U1201, Paris, France
| | - Brice Rotureau
- Trypanosome Cell Biology Unit, Institut Pasteur and INSERM U1201, Paris, France.,Trypanosome Transmission Group, Institut Pasteur, Paris, France
| |
Collapse
|
10
|
Ndung’u K, Murilla GA, Thuita JK, Ngae GN, Auma JE, Gitonga PK, Thungu DK, Kurgat RK, Chemuliti JK, Mdachi RE. Differential virulence of Trypanosoma brucei rhodesiense isolates does not influence the outcome of treatment with anti-trypanosomal drugs in the mouse model. PLoS One 2020; 15:e0229060. [PMID: 33151938 PMCID: PMC7643984 DOI: 10.1371/journal.pone.0229060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 07/04/2020] [Indexed: 11/19/2022] Open
Abstract
We assessed the virulence and anti-trypanosomal drug sensitivity patterns of Trypanosoma brucei rhodesiense (Tbr) isolates in the Kenya Agricultural and Livestock Research Organization-Biotechnology Research Institute (KALRO-BioRI) cryobank. Specifically, the study focused on Tbr clones originally isolated from the western Kenya/eastern Uganda focus of human African Trypanosomiasis (HAT). Twelve (12) Tbr clones were assessed for virulence using groups(n = 10) of Swiss White Mice monitored for 60 days post infection (dpi). Based on survival time, four classes of virulence were identified: (a) very-acute: 0-15, (b) acute: 16-30, (c) sub-acute: 31-45 and (d) chronic: 46-60 dpi. Other virulence biomarkers identified included: pre-patent period (pp), parasitaemia progression, packed cell volume (PCV) and body weight changes. The test Tbr clones together with KALRO-BioRi reference drug-resistant and drug sensitive isolates were then tested for sensitivity to melarsoprol (mel B), pentamidine, diminazene aceturate and suramin, using mice groups (n = 5) treated with single doses of each drug at 24 hours post infection. Our results showed that the clones were distributed among four classes of virulence as follows: 3/12 (very-acute), 3/12 (acute), 2/12 (sub-acute) and 4/12 (chronic) isolates. Differences in survivorship, parasitaemia progression and PCV were significant (P<0.001) and correlated. The isolate considered to be drug resistant at KALRO-BioRI, KETRI 2538, was confirmed to be resistant to melarsoprol, pentamidine and diminazene aceturate but it was not resistant to suramin. A cure rate of at least 80% was achieved for all test isolates with melarsoprol (1mg/Kg and 20 mg/kg), pentamidine (5 and 20 mg/kg), diminazene aceturate (5 mg/kg) and suramin (5 mg/kg) indicating that the isolates were not resistant to any of the drugs despite the differences in virulence. This study provides evidence of variations in virulence of Tbr clones from a single HAT focus and confirms that this variations is not a significant determinant of isolate sensitivity to anti-trypanosomal drugs.
Collapse
Affiliation(s)
- Kariuki Ndung’u
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- * E-mail:
| | - Grace Adira Murilla
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- KAG EAST University, Nairobi, Kenya
| | - John Kibuthu Thuita
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- Meru University of Science and Technology, Meru, Kenya
| | - Geoffrey Njuguna Ngae
- Food Crops Research Institute, Kenya Agricultural and Livestock Research Organization, Nairobi, Kenya
| | - Joanna Eseri Auma
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Purity Kaari Gitonga
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Daniel Kahiga Thungu
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Richard Kiptum Kurgat
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Judith Kusimba Chemuliti
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Raymond Ellie Mdachi
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| |
Collapse
|
11
|
Lecordier L, Uzureau S, Vanwalleghem G, Deleu M, Crowet JM, Barry P, Moran B, Voorheis P, Dumitru AC, Yamaryo-Botté Y, Dieu M, Tebabi P, Vanhollebeke B, Lins L, Botté CY, Alsteens D, Dufrêne Y, Pérez-Morga D, Nolan DP, Pays E. The Trypanosoma Brucei KIFC1 Kinesin Ensures the Fast Antibody Clearance Required for Parasite Infectivity. iScience 2020; 23:101476. [PMID: 32889430 PMCID: PMC7479354 DOI: 10.1016/j.isci.2020.101476] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 07/30/2020] [Accepted: 08/17/2020] [Indexed: 12/24/2022] Open
Abstract
Human innate immunity to Trypanosoma brucei involves the trypanosome C-terminal kinesin TbKIFC1, which transports internalized trypanolytic factor apolipoprotein L1 (APOL1) within the parasite. We show that TbKIFC1 preferentially associates with cholesterol-containing membranes and is indispensable for mammalian infectivity. Knockdown of TbKIFC1 did not affect trypanosome growth in vitro but rendered the parasites unable to infect mice unless antibody synthesis was compromised. Surface clearance of Variant Surface Glycoprotein (VSG)-antibody complexes was far slower in these cells, which were more susceptible to capture by macrophages. This phenotype was not due to defects in VSG expression or trafficking but to decreased VSG mobility in a less fluid, stiffer surface membrane. This change can be attributed to increased cholesterol level in the surface membrane in TbKIFC1 knockdown cells. Clearance of surface-bound antibodies by T. brucei is therefore essential for infectivity and depends on high membrane fluidity maintained by the cholesterol-trafficking activity of TbKIFC1.
Collapse
Affiliation(s)
- Laurence Lecordier
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des professeurs Jeener et Brachet, 6041 Gosselies, Belgium
| | - Sophie Uzureau
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des professeurs Jeener et Brachet, 6041 Gosselies, Belgium
| | - Gilles Vanwalleghem
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des professeurs Jeener et Brachet, 6041 Gosselies, Belgium
| | - Magali Deleu
- Laboratory of Molecular Biophysics at Interface (LBMI), University of Liège-Gembloux Agro Bio Tech, 2, Passage des Déportés, 5030 Gembloux, Belgium
| | - Jean-Marc Crowet
- Laboratory of Molecular Biophysics at Interface (LBMI), University of Liège-Gembloux Agro Bio Tech, 2, Passage des Déportés, 5030 Gembloux, Belgium
| | - Paul Barry
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland
| | - Barry Moran
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland
| | - Paul Voorheis
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland
| | - Andra-Cristina Dumitru
- Louvain Institute of Biomolecular Science and Technology, Catholic University of Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium
| | - Yoshiki Yamaryo-Botté
- Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, 38700 La Tronche, France
| | - Marc Dieu
- MaSUN, Mass Spectrometry Facility, University of Namur, 61 Rue de Bruxelles, 5000 Namur, Belgium
| | - Patricia Tebabi
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des professeurs Jeener et Brachet, 6041 Gosselies, Belgium
| | - Benoit Vanhollebeke
- Laboratory of Neurovascular Signaling, Université Libre de Bruxelles, 12, Rue des Profs Jeener et Brachet, 6041 Gosselies, Belgium
| | - Laurence Lins
- Laboratory of Molecular Biophysics at Interface (LBMI), University of Liège-Gembloux Agro Bio Tech, 2, Passage des Déportés, 5030 Gembloux, Belgium
| | - Cyrille Y. Botté
- Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, 38700 La Tronche, France
| | - David Alsteens
- Louvain Institute of Biomolecular Science and Technology, Catholic University of Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium
| | - Yves Dufrêne
- Louvain Institute of Biomolecular Science and Technology, Catholic University of Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium
| | - David Pérez-Morga
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des professeurs Jeener et Brachet, 6041 Gosselies, Belgium
- Center for Microscopy and Molecular Imaging (CMMI), Université Libre de Bruxelles, 12, Rue des Profs Jeener et Brachet, 6041 Gosselies, Belgium
| | - Derek P. Nolan
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland
| | - Etienne Pays
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des professeurs Jeener et Brachet, 6041 Gosselies, Belgium
| |
Collapse
|
12
|
Bhattacharya A, Corbeil A, do Monte-Neto RL, Fernandez-Prada C. Of Drugs and Trypanosomatids: New Tools and Knowledge to Reduce Bottlenecks in Drug Discovery. Genes (Basel) 2020; 11:genes11070722. [PMID: 32610603 PMCID: PMC7397081 DOI: 10.3390/genes11070722] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 12/15/2022] Open
Abstract
Leishmaniasis (Leishmania species), sleeping sickness (Trypanosoma brucei), and Chagas disease (Trypanosoma cruzi) are devastating and globally spread diseases caused by trypanosomatid parasites. At present, drugs for treating trypanosomatid diseases are far from ideal due to host toxicity, elevated cost, limited access, and increasing rates of drug resistance. Technological advances in parasitology, chemistry, and genomics have unlocked new possibilities for novel drug concepts and compound screening technologies that were previously inaccessible. In this perspective, we discuss current models used in drug-discovery cascades targeting trypanosomatids (from in vitro to in vivo approaches), their use and limitations in a biological context, as well as different examples of recently discovered lead compounds.
Collapse
Affiliation(s)
- Arijit Bhattacharya
- Department of Microbiology, Adamas University, Kolkata, West Bengal 700 126, India;
| | - Audrey Corbeil
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC J2S 2M2, Canada;
| | | | - Christopher Fernandez-Prada
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC J2S 2M2, Canada;
- Correspondence: ; Tel.: +1-450-773-8521 (ext. 32802)
| |
Collapse
|
13
|
Cayla M, McDonald L, MacGregor P, Matthews K. An atypical DYRK kinase connects quorum-sensing with posttranscriptional gene regulation in Trypanosoma brucei. eLife 2020; 9:e51620. [PMID: 32213288 PMCID: PMC7136023 DOI: 10.7554/elife.51620] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 03/25/2020] [Indexed: 02/07/2023] Open
Abstract
The sleeping sickness parasite, Trypanosoma brucei, uses quorum sensing (QS) to balance proliferation and transmission potential in the mammal bloodstream. A signal transduction cascade regulates this process, a component of which is a divergent member of the DYRK family of protein kinases, TbDYRK. Phylogenetic and mutational analysis in combination with activity and phenotypic assays revealed that TbDYRK exhibits a pre-activated conformation and an atypical HxY activation loop motif, unlike DYRK kinases in other eukaryotes. Phosphoproteomic comparison of TbDYRK null mutants with wild-type parasites identified molecules that operate on both the inhibitory 'slender retainer' and activatory 'stumpy inducer' arms of the QS control pathway. One of these molecules, the RNA-regulator TbZC3H20, regulates parasite QS, this being dependent on the integrity of its TbDYRK phosphorylation site. This analysis reveals fundamental differences to conventional DYRK family regulation and links trypanosome environmental sensing, signal transduction and developmental gene expression in a coherent pathway.
Collapse
Affiliation(s)
- Mathieu Cayla
- Institute for Immunology and Infection Research, School of Biological Sciences, Charlotte Auerbach Road, University of EdinburghEdinburghUnited Kingdom
| | - Lindsay McDonald
- Institute for Immunology and Infection Research, School of Biological Sciences, Charlotte Auerbach Road, University of EdinburghEdinburghUnited Kingdom
| | - Paula MacGregor
- Institute for Immunology and Infection Research, School of Biological Sciences, Charlotte Auerbach Road, University of EdinburghEdinburghUnited Kingdom
| | - Keith Matthews
- Institute for Immunology and Infection Research, School of Biological Sciences, Charlotte Auerbach Road, University of EdinburghEdinburghUnited Kingdom
| |
Collapse
|
14
|
Macleod OJS, Bart JM, MacGregor P, Peacock L, Savill NJ, Hester S, Ravel S, Sunter JD, Trevor C, Rust S, Vaughan TJ, Minter R, Mohammed S, Gibson W, Taylor MC, Higgins MK, Carrington M. A receptor for the complement regulator factor H increases transmission of trypanosomes to tsetse flies. Nat Commun 2020; 11:1326. [PMID: 32165615 PMCID: PMC7067766 DOI: 10.1038/s41467-020-15125-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 02/15/2020] [Indexed: 11/09/2022] Open
Abstract
Persistent pathogens have evolved to avoid elimination by the mammalian immune system including mechanisms to evade complement. Infections with African trypanosomes can persist for years and cause human and animal disease throughout sub-Saharan Africa. It is not known how trypanosomes limit the action of the alternative complement pathway. Here we identify an African trypanosome receptor for mammalian factor H, a negative regulator of the alternative pathway. Structural studies show how the receptor binds ligand, leaving inhibitory domains of factor H free to inactivate complement C3b deposited on the trypanosome surface. Receptor expression is highest in developmental stages transmitted to the tsetse fly vector and those exposed to blood meals in the tsetse gut. Receptor gene deletion reduced tsetse infection, identifying this receptor as a virulence factor for transmission. This demonstrates how a pathogen evolved a molecular mechanism to increase transmission to an insect vector by exploitation of a mammalian complement regulator.
Collapse
Affiliation(s)
- Olivia J S Macleod
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Jean-Mathieu Bart
- Intertryp, IRD, Cirad, University of Montpellier, Montpellier, France
| | - Paula MacGregor
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Lori Peacock
- School of Biological Sciences, University of Bristol, Bristol, BS8 1UG, UK
| | - Nicholas J Savill
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh, EH9 3JT, UK
| | - Svenja Hester
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Sophie Ravel
- Intertryp, IRD, Cirad, University of Montpellier, Montpellier, France
| | - Jack D Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford, OX3 0BP, UK
| | - Camilla Trevor
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
- Department of Antibody Discovery and Protein Engineering, AstraZeneca R&D, Granta Park, Cambridge, CB21 6GH, UK
| | - Steven Rust
- Department of Antibody Discovery and Protein Engineering, AstraZeneca R&D, Granta Park, Cambridge, CB21 6GH, UK
| | - Tristan J Vaughan
- Department of Antibody Discovery and Protein Engineering, AstraZeneca R&D, Granta Park, Cambridge, CB21 6GH, UK
| | - Ralph Minter
- Department of Antibody Discovery and Protein Engineering, AstraZeneca R&D, Granta Park, Cambridge, CB21 6GH, UK
| | - Shabaz Mohammed
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Wendy Gibson
- School of Biological Sciences, University of Bristol, Bristol, BS8 1UG, UK
| | - Martin C Taylor
- Faculty of Infectious and Tropical diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK.
| |
Collapse
|
15
|
Cooper S, Wadsworth ES, Ochsenreiter T, Ivens A, Savill NJ, Schnaufer A. Assembly and annotation of the mitochondrial minicircle genome of a differentiation-competent strain of Trypanosoma brucei. Nucleic Acids Res 2019; 47:11304-11325. [PMID: 31665448 PMCID: PMC6868439 DOI: 10.1093/nar/gkz928] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 10/03/2019] [Accepted: 10/08/2019] [Indexed: 01/10/2023] Open
Abstract
Kinetoplastids are protists defined by one of the most complex mitochondrial genomes in nature, the kinetoplast. In the sleeping sickness parasite Trypanosoma brucei, the kinetoplast is a chain mail-like network of two types of interlocked DNA molecules: a few dozen ∼23-kb maxicircles (homologs of the mitochondrial genome of other eukaryotes) and thousands of ∼1-kb minicircles. Maxicircles encode components of respiratory chain complexes and the mitoribosome. Several maxicircle-encoded mRNAs undergo extensive post-transcriptional RNA editing via addition and deletion of uridines. The process is mediated by hundreds of species of minicircle-encoded guide RNAs (gRNAs), but the precise number of minicircle classes and gRNA genes was unknown. Here we present the first essentially complete assembly and annotation of the kinetoplast genome of T. brucei. We have identified 391 minicircles, encoding not only ∼930 predicted 'canonical' gRNA genes that cover nearly all known editing events (accessible via the web at http://hank.bio.ed.ac.uk), but also ∼370 'non-canonical' gRNA genes of unknown function. Small RNA transcriptome data confirmed expression of the majority of both categories of gRNAs. Finally, we have used our data set to refine definitions for minicircle structure and to explore dynamics of minicircle copy numbers.
Collapse
Affiliation(s)
- Sinclair Cooper
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, UK
| | - Elizabeth S Wadsworth
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, UK
| | | | - Alasdair Ivens
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, UK
| | - Nicholas J Savill
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, UK
| | - Achim Schnaufer
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, UK
| |
Collapse
|
16
|
Developmental competence and antigen switch frequency can be uncoupled in Trypanosoma brucei. Proc Natl Acad Sci U S A 2019; 116:22774-22782. [PMID: 31636179 PMCID: PMC6842576 DOI: 10.1073/pnas.1912711116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Trypanosomes are blood-borne protozoa that cause human sleeping sickness and the livestock disease, nagana. These extracellular parasites sustain infection through their ability to change their surface proteins, a process called antigenic variation. They also promote their own transmission by development in the bloodstream to so-called “stumpy forms” generated in response to parasite density. Earlier studies have proposed that reduced capacity for stumpy formation also generates reduced antigen switch frequency, suggesting these processes are mechanistically coupled. Here, by silencing the density-sensing pathway or selecting parasites less able to generate stumpy forms, we demonstrate that these processes are under independent selection. This has relevance for parasite virulence, spread, and competition and for the selection of trypanosome species directly transmitted by biting flies. African trypanosomes use an extreme form of antigenic variation to evade host immunity, involving the switching of expressed variant surface glycoproteins by a stochastic and parasite-intrinsic process. Parasite development in the mammalian host is another feature of the infection dynamic, with trypanosomes undergoing quorum sensing (QS)-dependent differentiation between proliferative slender forms and arrested, transmissible, stumpy forms. Longstanding experimental studies have suggested that the frequency of antigenic variation and transmissibility may be linked, antigen switching being higher in developmentally competent, fly-transmissible, parasites (“pleomorphs”) than in serially passaged “monomorphic” lines that cannot transmit through flies. Here, we have directly tested this tenet of the infection dynamic by using 2 experimental systems to reduce pleomorphism. Firstly, lines were generated that inducibly lose developmental capacity through RNAi-mediated silencing of the QS signaling machinery (“inducible monomorphs”). Secondly, de novo lines were derived that have lost the capacity for stumpy formation by serial passage (“selected monomorphs”) and analyzed for their antigenic variation in comparison to isogenic preselected populations. Analysis of both inducible and selected monomorphs has established that antigen switch frequency and developmental capacity are independently selected traits. This generates the potential for diverse infection dynamics in different parasite populations where the rate of antigenic switching and transmission competence are uncoupled. Further, this may support the evolution, maintenance, and spread of important trypanosome variants such as Trypanosoma brucei evansi that exploit mechanical transmission.
Collapse
|
17
|
Tan W, Acevedo T, Harris EV, Alcaide TY, Walters JR, Hunter MD, Gerardo NM, Roode JC. Transcriptomics of monarch butterflies (
Danaus plexippus
) reveals that toxic host plants alter expression of detoxification genes and down‐regulate a small number of immune genes. Mol Ecol 2019; 28:4845-4863. [DOI: 10.1111/mec.15219] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 12/21/2022]
Affiliation(s)
- Wen‐Hao Tan
- Department of Biology Emory University Atlanta GA USA
| | - Tarik Acevedo
- Department of Biology Emory University Atlanta GA USA
- Department of Ecosystem Science and Management Pennsylvania State University State College PA USA
| | | | - Tiffanie Y. Alcaide
- Department of Biology Emory University Atlanta GA USA
- Department of Ecosystem Science and Management Pennsylvania State University State College PA USA
| | - James R. Walters
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence KS USA
| | - Mark D. Hunter
- Department of Ecology & Evolutionary Biology University of Michigan Ann Arbor MI USA
| | | | | |
Collapse
|
18
|
Tripathi A, Singha UK, Paromov V, Hill S, Pratap S, Rose K, Chaudhuri M. The Cross Talk between TbTim50 and PIP39, Two Aspartate-Based Protein Phosphatases, Maintains Cellular Homeostasis in Trypanosoma brucei. mSphere 2019; 4:e00353-19. [PMID: 31391278 PMCID: PMC6686227 DOI: 10.1128/msphere.00353-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 07/08/2019] [Indexed: 12/18/2022] Open
Abstract
Trypanosoma brucei, the infectious agent of a deadly disease known as African trypanosomiasis, undergoes various stresses during its digenetic life cycle. We previously showed that downregulation of T. brucei mitochondrial inner membrane protein translocase 50 (TbTim50), an aspartate-based protein phosphatase and a component of the translocase of the mitochondrial inner membrane (TIM), increased the tolerance of procyclic cells to oxidative stress. Using comparative proteomics analysis and further validating the proteomics results by immunoblotting, here we discovered that TbTim50 downregulation caused an approximately 5-fold increase in the levels of PIP39, which is also an aspartate-based protein phosphatase and is primarily localized in glycosomes. A moderate upregulation of a number of glycosomal enzymes was also noticed due to TbTim50 knockdown. We found that the rate of mitochondrial ATP production by oxidative phosphorylation decreased and that substrate-level phosphorylation increased due to depletion of TbTim50. These results were correlated with relative increases in the levels of trypanosome alternative oxidase and hexokinase and a reduced-growth phenotype in low-glucose medium. The levels and activity of the mitochondrial superoxide dismutase and glutaredoxin levels were increased due to TbTim50 knockdown. Furthermore, we show that TbTim50 downregulation increased the cellular AMP/ATP ratio, and as a consequence, phosphorylation of AMP-activated protein kinase (AMPK) was increased. Knocking down both TbTim50 and TbPIP39 reduced PIP39 levels as well as AMPK phosphorylation and reduced T. brucei tolerance to oxidative stress. These results suggest that TbTim50 and PIP39, two protein phosphatases in mitochondria and glycosomes, respectively, cross talk via the AMPK pathway to maintain cellular homeostasis in the procyclic form of T. bruceiIMPORTANCETrypanosoma brucei, the infectious agent of African trypanosomiasis, must adapt to strikingly different host environments during its digenetic life cycle. Developmental regulation of mitochondrial activities is an essential part of these processes. We have shown previously that mitochondrial inner membrane protein translocase 50 in T. brucei (TbTim50) possesses a dually specific phosphatase activity and plays a role in the cellular stress response pathway. Using proteomics analysis, here we have elucidated a novel connection between TbTim50 and a protein phosphatase of the same family, PIP39, which is also a differentiation-related protein localized in glycosomes. We found that these two protein phosphatases cross talk via the AMPK pathway and modulate cellular metabolic activities under stress. Together, our results indicate the importance of a TbTim50 and PIP39 cascade for communication between mitochondria and other cellular parts in regulation of cell homeostasis in T. brucei.
Collapse
Affiliation(s)
- Anuj Tripathi
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
| | - Ujjal K Singha
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
| | - Victor Paromov
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
| | - Salisha Hill
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Siddharth Pratap
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
| | - Kristie Rose
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Minu Chaudhuri
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
| |
Collapse
|
19
|
Maslov DA. Separating the Wheat from the Chaff: RNA Editing and Selection of Translatable mRNA in Trypanosome Mitochondria. Pathogens 2019; 8:pathogens8030105. [PMID: 31323762 PMCID: PMC6789859 DOI: 10.3390/pathogens8030105] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/14/2019] [Accepted: 07/16/2019] [Indexed: 11/16/2022] Open
Abstract
In the mitochondria of trypanosomes and related kinetoplastid protists, most mRNAs undergo a long and sophisticated maturation pathway before they can be productively translated by mitochondrial ribosomes. Some of the aspects of this pathway (identity of the promotors, transcription initiation, and termination signals) remain obscure, and some (post-transcriptional modification by U-insertion/deletion, RNA editing, 3′-end maturation) have been illuminated by research during the last decades. The RNA editing creates an open reading frame for a productive translation, but the fully edited mRNA often represents a minor fraction in the pool of pre-edited and partially edited precursors. Therefore, it has been expected that the final stages of the mRNA processing generate molecular hallmarks, which allow for the efficient and selective recognition of translation-competent templates. The general contours and several important details of this process have become known only recently and represent the subject of this review.
Collapse
Affiliation(s)
- Dmitri A Maslov
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA 92521, USA.
| |
Collapse
|
20
|
Rojas F, Silvester E, Young J, Milne R, Tettey M, Houston DR, Walkinshaw MD, Pérez-Pi I, Auer M, Denton H, Smith TK, Thompson J, Matthews KR. Oligopeptide Signaling through TbGPR89 Drives Trypanosome Quorum Sensing. Cell 2018; 176:306-317.e16. [PMID: 30503212 PMCID: PMC6333907 DOI: 10.1016/j.cell.2018.10.041] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 09/13/2018] [Accepted: 10/17/2018] [Indexed: 02/03/2023]
Abstract
Trypanosome parasites control their virulence and spread by using quorum sensing (QS) to generate transmissible “stumpy forms” in their host bloodstream. However, the QS signal “stumpy induction factor” (SIF) and its reception mechanism are unknown. Although trypanosomes lack G protein-coupled receptor signaling, we have identified a surface GPR89-family protein that regulates stumpy formation. TbGPR89 is expressed on bloodstream “slender form” trypanosomes, which receive the SIF signal, and when ectopically expressed, TbGPR89 drives stumpy formation in a SIF-pathway-dependent process. Structural modeling of TbGPR89 predicts unexpected similarity to oligopeptide transporters (POT), and when expressed in bacteria, TbGPR89 transports oligopeptides. Conversely, expression of an E. coli POT in trypanosomes drives parasite differentiation, and oligopeptides promote stumpy formation in vitro. Furthermore, the expression of secreted trypanosome oligopeptidases generates a paracrine signal that accelerates stumpy formation in vivo. Peptidase-generated oligopeptide QS signals being received through TbGPR89 provides a mechanism for both trypanosome SIF production and reception. Trypanosomes use quorum sensing to differentiate to transmissible stumpy forms A GPR89 protein with oligopeptide transport activity drives parasite differentiation Oligopeptide mixtures and synthetic di- and tripeptides promote stumpy formation Released parasite oligopeptidases generate the paracrine quorum sensing signal in vivo
Collapse
Affiliation(s)
- Federico Rojas
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Eleanor Silvester
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Julie Young
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Rachel Milne
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Mabel Tettey
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Douglas R Houston
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Malcolm D Walkinshaw
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Irene Pérez-Pi
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Manfred Auer
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Helen Denton
- School of Biology, BSRC, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, UK
| | - Terry K Smith
- School of Biology, BSRC, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, UK
| | - Joanne Thompson
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK.
| | - Keith R Matthews
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK.
| |
Collapse
|
21
|
Qiu Y, Milanes JE, Jones JA, Noorai RE, Shankar V, Morris JC. Glucose Signaling Is Important for Nutrient Adaptation during Differentiation of Pleomorphic African Trypanosomes. mSphere 2018; 3:e00366-18. [PMID: 30381351 PMCID: PMC6211221 DOI: 10.1128/msphere.00366-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/05/2018] [Indexed: 11/30/2022] Open
Abstract
The African trypanosome has evolved mechanisms to adapt to changes in nutrient availability that occur during its life cycle. During transition from mammalian blood to insect vector gut, parasites experience a rapid reduction in environmental glucose. Here we describe how pleomorphic parasites respond to glucose depletion with a focus on parasite changes in energy metabolism and growth. Long slender bloodstream form parasites were rapidly killed as glucose concentrations fell, while short stumpy bloodstream form parasites persisted to differentiate into the insect-stage procyclic form parasite. The rate of differentiation was lower than that triggered by other cues but reached physiological rates when combined with cold shock. Both differentiation and growth of resulting procyclic form parasites were inhibited by glucose and nonmetabolizable glucose analogs, and these parasites were found to have upregulated amino acid metabolic pathway component gene expression. In summary, glucose transitions from the primary metabolite of the blood-stage infection to a negative regulator of cell development and growth in the insect vector, suggesting that the hexose is not only a key metabolic agent but also an important signaling molecule.IMPORTANCE As the African trypanosome Trypanosoma brucei completes its life cycle, it encounters many different environments. Adaptation to these environments includes modulation of metabolic pathways to parallel the availability of nutrients. Here, we describe how the blood-dwelling life cycle stages of the African trypanosome, which consume glucose to meet their nutritional needs, respond differently to culture in the near absence of glucose. The proliferative long slender parasites rapidly die, while the nondividing short stumpy parasite remains viable and undergoes differentiation to the next life cycle stage, the procyclic form parasite. Interestingly, a sugar analog that cannot be used as an energy source inhibited the process. Furthermore, the growth of procyclic form parasite that resulted from the event was inhibited by glucose, a behavior that is similar to that of parasites isolated from tsetse flies. Our findings suggest that glucose sensing serves as an important modulator of nutrient adaptation in the parasite.
Collapse
Affiliation(s)
- Yijian Qiu
- Department of Genetics and Biochemistry, Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, USA
| | - Jillian E Milanes
- Department of Genetics and Biochemistry, Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, USA
| | - Jessica A Jones
- Department of Genetics and Biochemistry, Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, USA
| | - Rooksana E Noorai
- Clemson University Genomics & Computational Biology Laboratory, Clemson University, Clemson, South Carolina, USA
| | - Vijay Shankar
- Clemson University Genomics & Computational Biology Laboratory, Clemson University, Clemson, South Carolina, USA
| | - James C Morris
- Department of Genetics and Biochemistry, Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, USA
| |
Collapse
|
22
|
Silvester E, Ivens A, Matthews KR. A gene expression comparison of Trypanosoma brucei and Trypanosoma congolense in the bloodstream of the mammalian host reveals species-specific adaptations to density-dependent development. PLoS Negl Trop Dis 2018; 12:e0006863. [PMID: 30307943 PMCID: PMC6199001 DOI: 10.1371/journal.pntd.0006863] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/23/2018] [Accepted: 09/21/2018] [Indexed: 12/19/2022] Open
Abstract
In the bloodstream of mammalian hosts Trypanosoma brucei undergoes well-characterised density-dependent growth control and developmental adaptation for transmission. This involves the differentiation from proliferative, morphologically ‘slender’ forms to quiescent ‘stumpy’ forms that preferentially infect the tsetse fly vector. Another important livestock trypanosome, Trypanosoma congolense, also undergoes density-dependent cell-cycle arrest although this is not linked to obvious morphological transformation. Here we have compared the gene expression profile of T. brucei and T. congolense during the ascending phase of the parasitaemia and at peak parasitaemia in mice, analysing species and developmental differences between proliferating and cell-cycle arrested forms. Despite underlying conservation of their quorum sensing signalling pathway, each species exhibits distinct profiles of gene regulation when analysed by orthogroup and cell surface phylome profiling. This analysis of peak parasitaemia T. congolense provides the first molecular signatures of potential developmental competence, assisting life cycle developmental studies in these important livestock parasites. Furthermore, comparison with T. brucei identifies candidate molecules from each species that may be important for their survival in the mammalian host, transmission or distinct tropism in the tsetse vector. Animal African trypanosomiases are important diseases of livestock in sub-Saharan Africa. Two of the responsible parasite species are Trypanosoma brucei and Trypanosoma congolense, both being blood-borne parasites transmitted by tsetse flies. In T. brucei there is a well-characterised developmental event in the bloodstream that prepares the parasite for tsetse transmission—the generation of morphologically stumpy forms. In contrast, Trypanosoma congolense does not undergo the same obvious morphological event, but does respond to parasite density in the mammalian bloodstream by accumulating as a cell cycle arrested form. This prompted us to explore the adaptations of T. congolense in response to cell density in blood and to compare this with T. brucei. The datasets generated, and their analysis, represent a first detailed transcriptional profile for T. congolense and also a new high-resolution analysis of the developmental forms of T. brucei in a mammalian host. Critically, the analysis also carefully characterised the biological material used for RNA-seq analysis with respect to cell cycle status, morphology and the expression (in the case of T. brucei) of PAD1 –a molecular marker for stumpy forms. The manuscript highlights clear differences in the developmental adaptation of each parasite species, with T. congolense showing less extreme adaptation at peak parasitaemia than T. brucei. Nonetheless, several predicted surface protein families in T. congolense are strongly upregulated at high parasite density in the bloodstream, which may represent adaptations for their transmission or survival.
Collapse
Affiliation(s)
- Eleanor Silvester
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Alasdair Ivens
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Keith R. Matthews
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
| |
Collapse
|
23
|
McDonald L, Cayla M, Ivens A, Mony BM, MacGregor P, Silvester E, McWilliam K, Matthews KR. Non-linear hierarchy of the quorum sensing signalling pathway in bloodstream form African trypanosomes. PLoS Pathog 2018; 14:e1007145. [PMID: 29940034 PMCID: PMC6034907 DOI: 10.1371/journal.ppat.1007145] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 07/06/2018] [Accepted: 06/07/2018] [Indexed: 01/23/2023] Open
Abstract
Trypanosoma brucei, the agents of African trypanosomiasis, undergo density-dependent differentiation in the mammalian bloodstream to prepare for transmission by tsetse flies. This involves the generation of cell-cycle arrested, quiescent, stumpy forms from proliferative slender forms. The signalling pathway responsible for the quorum sensing response has been catalogued using a genome-wide selective screen, providing a compendium of signalling protein kinases phosphatases, RNA binding proteins and hypothetical proteins. However, the ordering of these components is unknown. To piece together these components to provide a description of how stumpy formation arises we have used an extragenic suppression approach. This exploited a combinatorial gene knockout and overexpression strategy to assess whether the loss of developmental competence in null mutants of pathway components could be compensated by ectopic expression of other components. We have created null mutants for three genes in the stumpy induction factor signalling pathway (RBP7, YAK, MEKK1) and evaluated complementation by expression of RBP7, NEK17, PP1-6, or inducible gene silencing of the proposed differentiation inhibitor TbTOR4. This indicated that the signalling pathway is non-linear. Phosphoproteomic analysis focused on one pathway component, a putative MEKK, identified molecules with altered expression and phosphorylation profiles in MEKK1 null mutants, including another component in the pathway, NEK17. Our data provide a first molecular dissection of multiple components in a signal transduction cascade in trypanosomes. African trypanosome parasites respond to density sensing information in the bloodstream of their mammalian hosts to generate their transmission stage, the stumpy form. Components of this ‘quorum sensing’ signalling cascade are known but their interactions and ordering are not. Here we have dissected the dependency relationships between molecules in the pathway by combinatorial gene knockout and ectopic expression, as well as by detailed phosphoproteomic analysis of one component. Our results provide a first analysis of the signal pathway architecture, revealing that it is non-linear. Moreover, phosphoproteome analysis reveals pathway hierarchy through identifying that the phosphorylation of a NEK kinase component of the pathway is reduced when a predicted upstream kinase is absent. This provides a framework for the coherent dissection of a signal transduction cascade in these parasites that use quorum sensing to control disease spread.
Collapse
Affiliation(s)
- Lindsay McDonald
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Mathieu Cayla
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Alasdair Ivens
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Binny M Mony
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Paula MacGregor
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Eleanor Silvester
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Kirsty McWilliam
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Keith R Matthews
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| |
Collapse
|
24
|
Cestari I, Anupama A, Stuart K. Inositol polyphosphate multikinase regulation of Trypanosoma brucei life stage development. Mol Biol Cell 2018. [PMID: 29514930 PMCID: PMC5921579 DOI: 10.1091/mbc.e17-08-0515] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The regulation of Trypanosoma brucei life stage development remains unclear. Inositol polyphosphate multikinase regulates the development of mammalian bloodforms to insect stages that normally develop in flies. Specific inositol phosphates, perhaps as second messengers, interact with proteins of the regulatory network that controls development. Many cellular processes change during the Trypanosoma brucei life cycle as this parasite alternates between the mammalian host and tsetse fly vector. We show that the inositol phosphate pathway helps regulate these developmental changes. Knockdown of inositol polyphosphate multikinase (IPMK), which phosphorylates Ins(1,4,5)P3 and Ins(1,3,4,5)P4, resulted in changes in bloodstream forms that are characteristic of insect stage procyclic forms. These changes include expression of the procyclic surface coat, up-regulation of RNA-binding proteins that we show to regulate stage-specific transcripts, and activation of oxidative phosphorylation with increased ATP production in bloodstream forms. These changes were accompanied by development of procyclic morphology, which also occurred by the expression of a catalytically inactive IPMK, implying that regulation of these processes entails IPMK activity. Proteins involved in signaling, protein synthesis and turnover, and metabolism were affinity-enriched with the IPMK substrate or product. Developmental changes associated with IPMK knockdown or catalytic inactivation reflected processes that are enriched with inositol phosphates, and chemical and genetic perturbation of these processes affected T. brucei development. Hence, IPMK helps regulate T. brucei development, perhaps by affecting inositol phosphate interactions with proteins of the regulatory network that controls energy metabolism and development.
Collapse
Affiliation(s)
- Igor Cestari
- Center for Infectious Disease Research, Seattle, WA 98109
| | - Atashi Anupama
- Center for Infectious Disease Research, Seattle, WA 98109
| | - Kenneth Stuart
- Center for Infectious Disease Research, Seattle, WA 98109.,Department of Global Health, University of Washington, Seattle, WA 98195
| |
Collapse
|
25
|
Abstract
Many pathogens evade host immunity by periodically changing the proteins they express on their surface - a phenomenon termed antigenic variation. An extreme form of antigenic variation, based around switching the composition of a Variant Surface Glycoprotein (VSG) coat, is exhibited by the African trypanosome Trypanosoma brucei, which causes human disease. The molecular details of VSG switching in T. brucei have been extensively studied over the last three decades, revealing in increasing detail the machinery and mechanisms by which VSG expression is controlled and altered. However, several key components of the models of T. brucei antigenic variation that have emerged have been challenged through recent discoveries. These discoveries include new appreciation of the importance of gene mosaics in generating huge levels of new VSG variants, the contributions of parasite development and body compartmentation in the host to the infection dynamics and, finally, potential differences in the strategies of antigenic variation and host infection used by the crucial livestock trypanosomes T. congolense and T. vivax. This review will discuss all these observations, which raise questions regarding how secure the existing models of trypanosome antigenic variation are. In addition, we will discuss the importance of continued mathematical modelling to understand the purpose of this widespread immune survival process.
Collapse
|
26
|
Moreno SA, Cantos GV. The kinetic properties of hexokinases in African trypanosomes of the subgenus Trypanozoon match the blood glucose levels of mammal hosts. Comp Biochem Physiol B Biochem Mol Biol 2017; 217:51-59. [PMID: 29277605 DOI: 10.1016/j.cbpb.2017.12.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 12/08/2017] [Accepted: 12/15/2017] [Indexed: 11/29/2022]
Abstract
We hypothesize that the hexokinases of trypanosomes of the subgenus Trypanozoon match the blood glucose levels of hosts. We studied the kinetic properties of purified hexokinase in T. equiperdum (specific activity=302U/mg), and compare with other members of Trypanozoon. With ATP (Km=104.7μM) as phosphate donor, hexokinase catalyzes the phosphorylation of glucose (Km=24.9μM) and mannose (Km=8.8μM). With respect to glucose, mannose and inorganic pyrophosphate respectively are a competitive, and a mixed inhibitor of hexokinase. With respect to ATP, both are mixed inhibitors of this enzyme. In T. equiperdum, hexokinase shows a high affinity for glucose. Pleomorphism-transformation of trypanosomes from a multiplicative to a non-multiplicative form-results in a self-limited growth stabilizing glucose consumption. It delays the death of the host, thus prolonging its exposure to tsetse flies. When glucose levels descend, top-down regulation allows trypanosomes to survive through the expression of alternative metabolic pathways. It accelerates the death of the host, but helps trypanosome density to increase enough to ensure transmission without tsetse flies. Pleomorphism, and a hexokinase with a high affinity for glucose, are two main adaptive traits of T. b. brucei. The latter trait, and a strong top-down regulation, are two main adaptive traits of T. equiperdum. For trypanosomes living in glucose-rich blood, a hexokinase with a high affinity for glucose would unnecessarily harm hosts. This may explain why the human parasites, T. b. gambiense and T. b. rhodesiense, possess hexokinases with a low affinity for glucose.
Collapse
Affiliation(s)
- S Andrea Moreno
- Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 05101, Venezuela.
| | | |
Collapse
|
27
|
Abstract
The African trypanosome was thought to primarily develop in the bloodstream and interstitial spaces of its mammalian host. In this issue of Cell Host & Microbe, Trindade et al. (2016) report the surprising finding that during ongoing persistent infections in mice, a major fraction of the parasites reside within fatty tissues.
Collapse
Affiliation(s)
- Stephen M Beverley
- Department of Molecular Microbiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
| |
Collapse
|
28
|
Silvester E, Young J, Ivens A, Matthews KR. Interspecies quorum sensing in co-infections can manipulate trypanosome transmission potential. Nat Microbiol 2017; 2:1471-1479. [PMID: 28871083 PMCID: PMC5660621 DOI: 10.1038/s41564-017-0014-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/27/2017] [Indexed: 11/21/2022]
Abstract
Quorum sensing (QS) is commonly used in microbial communities and some unicellular parasites to coordinate group behaviours1,2. An example is Trypanosoma brucei that causes Human African trypanosomiasis, as well as the livestock disease, nagana. Trypanosomes are spread by tsetse flies, transmission being enabled by cell-cycle arrested ‘stumpy forms’ that are generated in a density-dependent manner in mammalian blood. QS is mediated through a small (<500 Da), non-proteinaceous, stable but unidentified ‘stumpy induction factor’3, whose signal response pathway has been identified. Although QS is characterised in T. brucei, co-infections with other trypanosome species (T. congolense, T. vivax) are common in animals, generating the potential for interspecies interactions. Here, we show that T. congolense exhibits density-dependent growth control in vivo and conserves QS-regulatory genes, of which one can complement a T. brucei QS signal-blind mutant to restore stumpy formation. Thereafter we demonstrate that T. congolense-conditioned culture medium promotes T. brucei stumpy formation in vitro, dependent upon integrity of the QS signalling pathway. Finally, we show that, in vivo, co-infection with T. congolense accelerates differentiation to stumpy forms in T. brucei, this also being QS dependent. These cross-species interactions have important implications for trypanosome virulence, transmission, competition and evolution in the field.
Collapse
Affiliation(s)
- Eleanor Silvester
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Julie Young
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Alasdair Ivens
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Keith R Matthews
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK.
| |
Collapse
|
29
|
Silvester E, McWilliam KR, Matthews KR. The Cytological Events and Molecular Control of Life Cycle Development of Trypanosoma brucei in the Mammalian Bloodstream. Pathogens 2017; 6:pathogens6030029. [PMID: 28657594 PMCID: PMC5617986 DOI: 10.3390/pathogens6030029] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 12/21/2022] Open
Abstract
African trypanosomes cause devastating disease in sub-Saharan Africa in humans and livestock. The parasite lives extracellularly within the bloodstream of mammalian hosts and is transmitted by blood-feeding tsetse flies. In the blood, trypanosomes exhibit two developmental forms: the slender form and the stumpy form. The slender form proliferates in the bloodstream, establishes the parasite numbers and avoids host immunity through antigenic variation. The stumpy form, in contrast, is non-proliferative and is adapted for transmission. Here, we overview the features of slender and stumpy form parasites in terms of their cytological and molecular characteristics and discuss how these contribute to their distinct biological functions. Thereafter, we describe the technical developments that have enabled recent discoveries that uncover how the slender to stumpy transition is enacted in molecular terms. Finally, we highlight new understanding of how control of the balance between slender and stumpy form parasites interfaces with other components of the infection dynamic of trypanosomes in their mammalian hosts. This interplay between the host environment and the parasite’s developmental biology may expose new vulnerabilities to therapeutic attack or reveal where drug control may be thwarted by the biological complexity of the parasite’s lifestyle.
Collapse
Affiliation(s)
- Eleanor Silvester
- Institute for Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, King's Buildings, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK.
| | - Kirsty R McWilliam
- Institute for Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, King's Buildings, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK.
| | - Keith R Matthews
- Institute for Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, King's Buildings, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK.
| |
Collapse
|
30
|
Stijlemans B, Radwanska M, De Trez C, Magez S. African Trypanosomes Undermine Humoral Responses and Vaccine Development: Link with Inflammatory Responses? Front Immunol 2017; 8:582. [PMID: 28596768 PMCID: PMC5442186 DOI: 10.3389/fimmu.2017.00582] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/01/2017] [Indexed: 01/15/2023] Open
Abstract
African trypanosomosis is a debilitating disease of great medical and socioeconomical importance. It is caused by strictly extracellular protozoan parasites capable of infecting all vertebrate classes including human, livestock, and game animals. To survive within their mammalian host, trypanosomes have evolved efficient immune escape mechanisms and manipulate the entire host immune response, including the humoral response. This report provides an overview of how trypanosomes initially trigger and subsequently undermine the development of an effective host antibody response. Indeed, results available to date obtained in both natural and experimental infection models show that trypanosomes impair homeostatic B-cell lymphopoiesis, B-cell maturation and survival and B-cell memory development. Data on B-cell dysfunctioning in correlation with parasite virulence and trypanosome-mediated inflammation will be discussed, as well as the impact of trypanosomosis on heterologous vaccine efficacy and diagnosis. Therefore, new strategies aiming at enhancing vaccination efficacy could benefit from a combination of (i) early parasite diagnosis, (ii) anti-trypanosome (drugs) treatment, and (iii) anti-inflammatory treatment that collectively might allow B-cell recovery and improve vaccination.
Collapse
Affiliation(s)
- Benoit Stijlemans
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Myeloid Cell Immunology Lab, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Magdalena Radwanska
- Laboratory for Biomedical Research, Ghent University Global Campus, Yeonsu-Gu, Incheon, South Korea
| | - Carl De Trez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Structural Biology Research Centre (SBRC), VIB, Brussels, Belgium
| | - Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Laboratory for Biomedical Research, Ghent University Global Campus, Yeonsu-Gu, Incheon, South Korea
| |
Collapse
|
31
|
Abstract
Cellular metabolic activity is a highly complex, dynamic, regulated process that is influenced by numerous factors, including extracellular environmental signals, nutrient availability and the physiological and developmental status of the cell. The causative agent of sleeping sickness,
Trypanosoma brucei, is an exclusively extracellular protozoan parasite that encounters very different extracellular environments during its life cycle within the mammalian host and tsetse fly insect vector. In order to meet these challenges, there are significant alterations in the major energetic and metabolic pathways of these highly adaptable parasites. This review highlights some of these metabolic changes in this early divergent eukaryotic model organism.
Collapse
Affiliation(s)
- Terry K Smith
- Biomedical Sciences Research Complex, University of St Andrews, Fife, UK
| | - Frédéric Bringaud
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), UMR 5234 CNRS, Université de Bordeaux, Bordeaux, France
| | - Derek P Nolan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| |
Collapse
|
32
|
Abstract
Cellular metabolic activity is a highly complex, dynamic, regulated process that is influenced by numerous factors, including extracellular environmental signals, nutrient availability and the physiological and developmental status of the cell. The causative agent of sleeping sickness, Trypanosoma brucei, is an exclusively extracellular protozoan parasite that encounters very different extracellular environments during its life cycle within the mammalian host and tsetse fly insect vector. In order to meet these challenges, there are significant alterations in the major energetic and metabolic pathways of these highly adaptable parasites. This review highlights some of these metabolic changes in this early divergent eukaryotic model organism.
Collapse
Affiliation(s)
- Terry K Smith
- Biomedical Sciences Research Complex, University of St Andrews, Fife, UK
| | - Frédéric Bringaud
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), UMR 5234 CNRS, Université de Bordeaux, Bordeaux, France
| | - Derek P Nolan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| |
Collapse
|
33
|
Zimmermann H, Subota I, Batram C, Kramer S, Janzen CJ, Jones NG, Engstler M. A quorum sensing-independent path to stumpy development in Trypanosoma brucei. PLoS Pathog 2017; 13:e1006324. [PMID: 28394929 PMCID: PMC5398725 DOI: 10.1371/journal.ppat.1006324] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 04/20/2017] [Accepted: 03/29/2017] [Indexed: 11/19/2022] Open
Abstract
For persistent infections of the mammalian host, African trypanosomes limit their population size by quorum sensing of the parasite-excreted stumpy induction factor (SIF), which induces development to the tsetse-infective stumpy stage. We found that besides this cell density-dependent mechanism, there exists a second path to the stumpy stage that is linked to antigenic variation, the main instrument of parasite virulence. The expression of a second variant surface glycoprotein (VSG) leads to transcriptional attenuation of the VSG expression site (ES) and immediate development to tsetse fly infective stumpy parasites. This path is independent of SIF and solely controlled by the transcriptional status of the ES. In pleomorphic trypanosomes varying degrees of ES-attenuation result in phenotypic plasticity. While full ES-attenuation causes irreversible stumpy development, milder attenuation may open a time window for rescuing an unsuccessful antigenic switch, a scenario that so far has not been considered as important for parasite survival.
Collapse
Affiliation(s)
- Henriette Zimmermann
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Ines Subota
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Christopher Batram
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Susanne Kramer
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Christian J. Janzen
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Nicola G. Jones
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Markus Engstler
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
- * E-mail:
| |
Collapse
|
34
|
Rico E, Ivens A, Glover L, Horn D, Matthews KR. Genome-wide RNAi selection identifies a regulator of transmission stage-enriched gene families and cell-type differentiation in Trypanosoma brucei. PLoS Pathog 2017; 13:e1006279. [PMID: 28334017 PMCID: PMC5380359 DOI: 10.1371/journal.ppat.1006279] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 04/04/2017] [Accepted: 03/08/2017] [Indexed: 01/07/2023] Open
Abstract
Trypanosoma brucei, causing African sleeping-sickness, exploits quorum-sensing (QS) to generate the ‘stumpy forms’ necessary for the parasite’s transmission to tsetse-flies. These quiescent cells are generated by differentiation in the bloodstream from proliferative slender forms. Using genome-wide RNAi selection we screened for repressors of transmission stage-enriched mRNAs in slender forms, using the stumpy-elevated ESAG9 transcript as a model. This identified REG9.1, whose RNAi-silencing alleviated ESAG9 repression in slender forms and tsetse-midgut procyclic forms. Interestingly, trypanosome surface protein Family 5 and Family 7 mRNAs were also elevated, which, like ESAG9, are T. brucei specific and stumpy-enriched. We suggest these contribute to the distinct transmission biology and vector tropism of T. brucei from other African trypanosome species. As well as surface family regulation, REG9.1-depletion generated QS-independent development to stumpy forms in vivo, whereas REG9.1 overexpression in bloodstream forms potentiated spontaneous differentiation to procyclic forms in the absence of an external signal. Combined, this identifies REG9.1 as a regulator of developmental cell fate, controlling the expression of Trypanosoma brucei-specific molecules elevated during transmission. African trypanosomes cause important disease of humans and livestock in sub Saharan Africa and are transmitted by tsetse flies. In preparation for transmission, Trypanosoma brucei uses quorum sensing to generate ‘stumpy forms’ that are arrested and express a distinct subset of genes to the ‘slender forms’ that proliferate to establish the parasitaemia in the bloodstream. This necessitates that stumpy-enriched transcripts are repressed in slender forms, although the molecular control of this is unknown. Here, we have developed a genome-wide selectional strategy to isolate repressors of stumpy-enriched genes, and successfully identified a novel regulatory molecule, termed REG9.1. Silencing of REG9.1 alleviates the repression of the previously characterised stumpy-enriched ESAG9 gene family, and also two novel predicted surface protein families that are specific to Trypansoma brucei but absent from other African trypanosome species. REG9.1 silencing also drives density-independent differentiation to stumpy forms, whereas its ectopic expression in bloodstream forms potentiates differentiation to tsetse midgut procyclic forms in the absence of an external signal. REG9.1 is therefore identified as a novel developmental regulator whose action may contribute to the species-specific transmission biology of Trypanosoma brucei, which differs from that of either Trypanosoma congolense or Trypanosoma vivax.
Collapse
Affiliation(s)
- Eva Rico
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Alasdair Ivens
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Lucy Glover
- The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - David Horn
- The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Keith R. Matthews
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- * E-mail:
| |
Collapse
|
35
|
Silva-Barrios S, Stäger S. Protozoan Parasites and Type I IFNs. Front Immunol 2017; 8:14. [PMID: 28154565 PMCID: PMC5243830 DOI: 10.3389/fimmu.2017.00014] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 01/05/2017] [Indexed: 12/16/2022] Open
Abstract
For many years, the role of interferon (IFN)-I has been characterized primarily in the context of viral infections. However, regulatory functions mediated by IFN-I have also been described against bacterial infections and in tumor immunology. Only recently, the interest in understanding the immune functions mediated by IFN-I has dramatically increased in the field of protozoan infections. In this review, we discuss the discrete role of IFN-I in the immune response against major protozoan infections: Plasmodium, Leishmania, Trypanosoma, and Toxoplasma.
Collapse
Affiliation(s)
- Sasha Silva-Barrios
- INRS-Institut Armand Frappier, Center for Host-Parasite Interactions , Laval, QC , Canada
| | - Simona Stäger
- INRS-Institut Armand Frappier, Center for Host-Parasite Interactions , Laval, QC , Canada
| |
Collapse
|
36
|
Doehl JSP, Sádlová J, Aslan H, Pružinová K, Metangmo S, Votýpka J, Kamhawi S, Volf P, Smith DF. Leishmania HASP and SHERP Genes Are Required for In Vivo Differentiation, Parasite Transmission and Virulence Attenuation in the Host. PLoS Pathog 2017; 13:e1006130. [PMID: 28095465 PMCID: PMC5271408 DOI: 10.1371/journal.ppat.1006130] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 01/27/2017] [Accepted: 12/15/2016] [Indexed: 12/15/2022] Open
Abstract
Differentiation of extracellular Leishmania promastigotes within their sand fly vector, termed metacyclogenesis, is considered to be essential for parasites to regain mammalian host infectivity. Metacyclogenesis is accompanied by changes in the local parasite environment, including secretion of complex glycoconjugates within the promastigote secretory gel and colonization and degradation of the sand fly stomodeal valve. Deletion of the stage-regulated HASP and SHERP genes on chromosome 23 of Leishmania major is known to stall metacyclogenesis in the sand fly but not in in vitro culture. Here, parasite mutants deficient in specific genes within the HASP/SHERP chromosomal region have been used to investigate their role in metacyclogenesis, parasite transmission and establishment of infection. Metacyclogenesis was stalled in HASP/SHERP mutants in vivo and, although still capable of osmotaxis, these mutants failed to secrete promastigote secretory gel, correlating with a lack of parasite accumulation in the thoracic midgut and failure to colonise the stomodeal valve. These defects prevented parasite transmission to a new mammalian host. Sand fly midgut homogenates modulated parasite behaviour in vitro, suggesting a role for molecular interactions between parasite and vector in Leishmania development within the sand fly. For the first time, stage-regulated expression of the small HASPA proteins in Leishmania (Leishmania) has been demonstrated: HASPA2 is expressed only in extracellular promastigotes and HASPA1 only in intracellular amastigotes. Despite its lack of expression in amastigotes, replacement of HASPA2 into the null locus background delays onset of pathology in BALB/c mice. This HASPA2-dependent effect is reversed by HASPA1 gene addition, suggesting that the HASPAs may have a role in host immunomodulation.
Collapse
Affiliation(s)
- Johannes S. P. Doehl
- Centre for Immunology and Infection, Department of Biology, University of York, York, United Kingdom
| | - Jovana Sádlová
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Hamide Aslan
- Vector Molecular Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Kateřina Pružinová
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Sonia Metangmo
- Vector Molecular Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Jan Votýpka
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Shaden Kamhawi
- Vector Molecular Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Petr Volf
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Deborah F. Smith
- Centre for Immunology and Infection, Department of Biology, University of York, York, United Kingdom
| |
Collapse
|
37
|
Savage AF, Kolev NG, Franklin JB, Vigneron A, Aksoy S, Tschudi C. Transcriptome Profiling of Trypanosoma brucei Development in the Tsetse Fly Vector Glossina morsitans. PLoS One 2016; 11:e0168877. [PMID: 28002435 PMCID: PMC5176191 DOI: 10.1371/journal.pone.0168877] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 12/07/2016] [Indexed: 01/10/2023] Open
Abstract
African trypanosomes, the causative agents of sleeping sickness in humans and nagana in animals, have a complex digenetic life cycle between a mammalian host and an insect vector, the blood-feeding tsetse fly. Although the importance of the insect vector to transmit the disease was first realized over a century ago, many aspects of trypanosome development in tsetse have not progressed beyond a morphological analysis, mainly due to considerable challenges to obtain sufficient material for molecular studies. Here, we used high-throughput RNA-Sequencing (RNA-Seq) to profile Trypanosoma brucei transcript levels in three distinct tissues of the tsetse fly, namely the midgut, proventriculus and salivary glands. Consistent with current knowledge and providing a proof of principle, transcripts coding for procyclin isoforms and several components of the cytochrome oxidase complex were highly up-regulated in the midgut transcriptome, whereas transcripts encoding metacyclic VSGs (mVSGs) and the surface coat protein brucei alanine rich protein or BARP were extremely up-regulated in the salivary gland transcriptome. Gene ontology analysis also supported the up-regulation of biological processes such as DNA metabolism and DNA replication in the proventriculus transcriptome and major changes in signal transduction and cyclic nucleotide metabolism in the salivary gland transcriptome. Our data highlight a small repertoire of expressed mVSGs and potential signaling pathways involving receptor-type adenylate cyclases and members of a surface carboxylate transporter family, called PADs (Proteins Associated with Differentiation), to cope with the changing environment, as well as RNA-binding proteins as a possible global regulators of gene expression.
Collapse
Affiliation(s)
- Amy F. Savage
- Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America
| | - Nikolay G. Kolev
- Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America
| | - Joseph B. Franklin
- Department of Cell Biology, School of Medicine, Yale University, New Haven, Connecticut, United States of America
| | - Aurelien Vigneron
- Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America
| | - Serap Aksoy
- Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America
- * E-mail: (SA); (CT)
| | - Christian Tschudi
- Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America
- * E-mail: (SA); (CT)
| |
Collapse
|
38
|
Tanowitz HB, Scherer PE, Mota MM, Figueiredo LM. Adipose Tissue: A Safe Haven for Parasites? Trends Parasitol 2016; 33:276-284. [PMID: 28007406 DOI: 10.1016/j.pt.2016.11.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/17/2016] [Accepted: 11/28/2016] [Indexed: 12/13/2022]
Abstract
Adipose tissue (AT) is no longer regarded as an inert lipid storage, but as an important central regulator in energy homeostasis and immunity. Three parasite species are uniquely associated with AT during part of their life cycle: Trypanosoma cruzi, the causative agent of Chagas disease; Trypanosoma brucei, the causative agent of African sleeping sickness; and Plasmodium spp., the causative agents of malaria. In AT, T. cruzi resides inside adipocytes, T. brucei is found in the interstitial spaces between adipocytes, while Plasmodium spp. infect red blood cells, which may adhere to the blood vessels supplying AT. Here, we discuss how each parasite species adapts to this tissue environment and what the implications are for pathogenesis, clinical manifestations, and therapy.
Collapse
Affiliation(s)
- Herbert B Tanowitz
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8549, USA; Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Maria M Mota
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
| |
Collapse
|
39
|
Mugnier MR, Stebbins CE, Papavasiliou FN. Masters of Disguise: Antigenic Variation and the VSG Coat in Trypanosoma brucei. PLoS Pathog 2016; 12:e1005784. [PMID: 27583379 PMCID: PMC5008768 DOI: 10.1371/journal.ppat.1005784] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Monica R. Mugnier
- The Rockefeller University, Laboratory of Lymphocyte Biology, New York, New York, United States of America
| | - C. Erec Stebbins
- The Rockefeller University, Laboratory of Structural Microbiology, New York, New York, United States of America
| | - F. Nina Papavasiliou
- The Rockefeller University, Laboratory of Lymphocyte Biology, New York, New York, United States of America
- * E-mail:
| |
Collapse
|
40
|
Stijlemans B, Caljon G, Van Den Abbeele J, Van Ginderachter JA, Magez S, De Trez C. Immune Evasion Strategies of Trypanosoma brucei within the Mammalian Host: Progression to Pathogenicity. Front Immunol 2016; 7:233. [PMID: 27446070 PMCID: PMC4919330 DOI: 10.3389/fimmu.2016.00233] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/30/2016] [Indexed: 12/26/2022] Open
Abstract
The diseases caused by African trypanosomes (AT) are of both medical and veterinary importance and have adversely influenced the economic development of sub-Saharan Africa. Moreover, so far not a single field applicable vaccine exists, and chemotherapy is the only strategy available to treat the disease. These strictly extracellular protozoan parasites are confronted with different arms of the host's immune response (cellular as well as humoral) and via an elaborate and efficient (vector)-parasite-host interplay they have evolved efficient immune escape mechanisms to evade/manipulate the entire host immune response. This is of importance, since these parasites need to survive sufficiently long in their mammalian/vector host in order to complete their life cycle/transmission. Here, we will give an overview of the different mechanisms AT (i.e. T. brucei as a model organism) employ, comprising both tsetse fly saliva and parasite-derived components to modulate host innate immune responses thereby sculpturing an environment that allows survival and development within the mammalian host.
Collapse
Affiliation(s)
- Benoît Stijlemans
- Laboratory of Myeloid Cell Immunology, VIB Inflammation Research Center, Ghent, Belgium; Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Guy Caljon
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Wilrijk, Belgium; Unit of Veterinary Protozoology, Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp (ITM), Antwerp, Belgium
| | - Jan Van Den Abbeele
- Unit of Veterinary Protozoology, Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp (ITM) , Antwerp , Belgium
| | - Jo A Van Ginderachter
- Laboratory of Myeloid Cell Immunology, VIB Inflammation Research Center, Ghent, Belgium; Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium; Department of Structural Biology, VIB, Brussels, Belgium
| | - Carl De Trez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium; Department of Structural Biology, VIB, Brussels, Belgium
| |
Collapse
|
41
|
Trindade S, Rijo-Ferreira F, Carvalho T, Pinto-Neves D, Guegan F, Aresta-Branco F, Bento F, Young SA, Pinto A, Van Den Abbeele J, Ribeiro RM, Dias S, Smith TK, Figueiredo LM. Trypanosoma brucei Parasites Occupy and Functionally Adapt to the Adipose Tissue in Mice. Cell Host Microbe 2016; 19:837-48. [PMID: 27237364 PMCID: PMC4906371 DOI: 10.1016/j.chom.2016.05.002] [Citation(s) in RCA: 221] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/21/2016] [Accepted: 04/30/2016] [Indexed: 11/17/2022]
Abstract
Trypanosoma brucei is an extracellular parasite that causes sleeping sickness. In mammalian hosts, trypanosomes are thought to exist in two major niches: early in infection, they populate the blood; later, they breach the blood-brain barrier. Working with a well-established mouse model, we discovered that adipose tissue constitutes a third major reservoir for T. brucei. Parasites from adipose tissue, here termed adipose tissue forms (ATFs), can replicate and were capable of infecting a naive animal. ATFs were transcriptionally distinct from bloodstream forms, and the genes upregulated included putative fatty acid β-oxidation enzymes. Consistent with this, ATFs were able to utilize exogenous myristate and form β-oxidation intermediates, suggesting that ATF parasites can use fatty acids as an external carbon source. These findings identify the adipose tissue as a niche for T. brucei during its mammalian life cycle and could potentially explain the weight loss associated with sleeping sickness. T. brucei parasites accumulate in the adipose tissue early after mouse infection Adipose tissue forms (ATFs) can replicate and are capable of infecting naive mice ATFs are transcriptionally distinct and upregulate genes for fatty acid metabolism ATFs can actively uptake exogenous myristate and form β-oxidation intermediates
Collapse
Affiliation(s)
- Sandra Trindade
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Filipa Rijo-Ferreira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal; Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA; Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4099-002 Porto, Portugal
| | - Tânia Carvalho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Daniel Pinto-Neves
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Fabien Guegan
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Francisco Aresta-Branco
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Fabio Bento
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Simon A Young
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK
| | - Andreia Pinto
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Jan Van Den Abbeele
- Department of Biomedical Sciences, Unit of Veterinary Protozoology, Institute of Tropical Medicine Antwerp, B-2000 Antwerp, Belgium; Department of Physiology, Laboratory of Zoophysiology, University of Ghent, B-9000 Ghent, Belgium
| | - Ruy M Ribeiro
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA; Guest Professor, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Sérgio Dias
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Terry K Smith
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal.
| |
Collapse
|
42
|
Bassarak B, Moser I, Menge C. In vitro production of Trypanosoma equiperdum antigen and its evaluation for use in serodiagnosis of dourine. Vet Parasitol 2016; 223:133-40. [PMID: 27198790 DOI: 10.1016/j.vetpar.2016.04.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 04/19/2016] [Accepted: 04/20/2016] [Indexed: 11/19/2022]
Abstract
A modified Baltz's in vitro cultivation system for the propagation of Trypanosoma equiperdum strain OVI was established to develop a replacement for the conventional production procedure of dourine diagnostic antigen in rats. To increase trypanosome yields we designed an optimized culture medium by addition of supplemental compounds. Trypanosomes were adapted to this medium by two succeeding cultivation steps which led to a substantial proliferation rate and an increased cell density tolerance, respectively. As a result, adapted parasites could be propagated to maximum cell densities of >2×10(6) cells/ml, facilitating in vitro antigen production in preparative quantities comparable to the conventional method. A panel of 180 horse field sera, previously sent for testing to the German National Reference Laboratory for Dourine, was tested by complement fixation test using culture-derived as well as conventionally produced dourine antigen. Cohen's kappa values for results obtained with two batches of culture-derived antigen as compared to conventional antigen were 0.91 (95% confidence interval [CI]: 82.2-99.7) and 0.83 (95% CI: 70.3-95.3), respectively. Performance of antigens for diagnostic purposes was characterized in an inter-laboratory comparative study deploying 14 sera from horses with defined dourine statuses. Complement fixation test results from 15 participating European laboratories showed a diagnostic sensitivity of 94.1% (95% CI: 89.4-98.7) and a diagnostic specificity of 96.2% (95% CI: 92.5-99.9) for conventional antigen and a slightly higher diagnostic sensitivity of 96.0% (95% CI: 92.2-99.8) and a diagnostic specificity of 97.1% (95% CI: 94.0-100) for culture-derived antigen. We conclude that our novel approach for dourine antigen production from in vitro-grown trypanosomes described and evaluated herein meets the requirements for the prospective purpose in quantitative and qualitative terms and should be considered by the competent authorities as an alternative for the animal experiment currently prescribed by international standards.
Collapse
Affiliation(s)
- Björn Bassarak
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, Naumburger Straße 96a, 07743 Jena, Germany; German National Reference Laboratory for Dourine, Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, Naumburger Straße 96a, 07743 Jena, Germany.
| | - Irmgard Moser
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, Naumburger Straße 96a, 07743 Jena, Germany; German National Reference Laboratory for Dourine, Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, Naumburger Straße 96a, 07743 Jena, Germany.
| | - Christian Menge
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, Naumburger Straße 96a, 07743 Jena, Germany.
| |
Collapse
|
43
|
Matthews KR, McCulloch R, Morrison LJ. The within-host dynamics of African trypanosome infections. Philos Trans R Soc Lond B Biol Sci 2016; 370. [PMID: 26150654 PMCID: PMC4528486 DOI: 10.1098/rstb.2014.0288] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
African trypanosomes are single-celled protozoan parasites that are capable of long-term survival while living extracellularly in the bloodstream and tissues of mammalian hosts. Prolonged infections are possible because trypanosomes undergo antigenic variation-the expression of a large repertoire of antigenically distinct surface coats, which allows the parasite population to evade antibody-mediated elimination. The mechanisms by which antigen genes become activated influence their order of expression, most likely by influencing the frequency of productive antigen switching, which in turn is likely to contribute to infection chronicity. Superimposed upon antigen switching as a contributor to trypanosome infection dynamics is the density-dependent production of cell-cycle arrested parasite transmission stages, which limit the infection while ensuring parasite spread to new hosts via the bite of blood-feeding tsetse flies. Neither antigen switching nor developmental progression to transmission stages is driven by the host. However, the host can contribute to the infection dynamic through the selection of distinct antigen types, the influence of genetic susceptibility or trypanotolerance and the potential influence of host-dependent effects on parasite virulence, development of transmission stages and pathogenicity. In a zoonotic infection cycle where trypanosomes circulate within a range of host animal populations, and in some cases humans, there is considerable scope for a complex interplay between parasite immune evasion, transmission potential and host factors to govern the profile and outcome of infection.
Collapse
Affiliation(s)
- Keith R Matthews
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK
| | - Richard McCulloch
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Sir Graeme Davies Building, 120 University Place, Glasgow G12 8TA, UK
| | - Liam J Morrison
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK
| |
Collapse
|
44
|
Avila CCDC, Peacock L, Machado FC, Gibson W, Schenkman S, Carrington M, Castilho BA. Phosphorylation of eIF2α on Threonine 169 is not required for Trypanosoma brucei cell cycle arrest during differentiation. Mol Biochem Parasitol 2016; 205:16-21. [PMID: 26996431 PMCID: PMC4850487 DOI: 10.1016/j.molbiopara.2016.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 11/17/2022]
Abstract
Pleomorphic T. brucei expressing an eIF2α phosphorylation site mutant were made. The mutation did not prevent normal arrest and differentiation into stumpy forms. Mutants differentiate into procyclic forms in vitro and in tsetse flies.
The trypanosome life cycle consists of a series of developmental forms each adapted to an environment in the relevant insect and/or mammalian host. The differentiation process from the mammalian bloodstream form to the insect-midgut procyclic form in Trypanosoma brucei occurs in two steps in vivo. First proliferating ‘slender' bloodstream forms differentiate to non-dividing ‘stumpy' forms arrested in G1. Second, in response to environmental cues, stumpy bloodstream forms re-enter the cell cycle and start to proliferate as procyclic forms after a lag during which both cell morphology and gene expression are modified. Nearly all arrested cells have lower rates of protein synthesis when compared to the proliferating equivalent. In eukaryotes, one mechanism used to regulate the overall rate of protein synthesis involves phosphorylation of the alpha subunit of initiation factor eIF2 (eIF2α). The effect of eIF2α phosphorylation is to prevent the action of eIF2B, the guanine nucleotide exchange factor that activates eIF2 for the next rounds of initiation. To investigate the role of the phosphorylation of eIF2α in the life cycle of T. brucei, a cell line was made with a single eIF2α gene that contained the phosphorylation site, threonine 169, mutated to alanine. These cells were capable of differentiating from proliferating bloodstream form cells into arrested stumpy forms in mice and into procyclic forms in vitro and in tsetse flies. These results indicate that translation attenuation mediated by the phosphorylation of eIF2α on threonine 169 is not necessary for the cell cycle arrest associated with these differentiation processes.
Collapse
Affiliation(s)
- Carla Cristi D C Avila
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Lori Peacock
- Department of Clinical Veterinary Science, University of Bristol, Langford, Bristol BS40 5DU, UK; School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Fabricio Castro Machado
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Wendy Gibson
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Sergio Schenkman
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
| | - Beatriz A Castilho
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil.
| |
Collapse
|
45
|
DNA Recombination Strategies During Antigenic Variation in the African Trypanosome. Microbiol Spectr 2016; 3:MDNA3-0016-2014. [PMID: 26104717 DOI: 10.1128/microbiolspec.mdna3-0016-2014] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Survival of the African trypanosome in its mammalian hosts has led to the evolution of antigenic variation, a process for evasion of adaptive immunity that has independently evolved in many other viral, bacterial and eukaryotic pathogens. The essential features of trypanosome antigenic variation have been understood for many years and comprise a dense, protective Variant Surface Glycoprotein (VSG) coat, which can be changed by recombination-based and transcription-based processes that focus on telomeric VSG gene transcription sites. However, it is only recently that the scale of this process has been truly appreciated. Genome sequencing of Trypanosoma brucei has revealed a massive archive of >1000 VSG genes, the huge majority of which are functionally impaired but are used to generate far greater numbers of VSG coats through segmental gene conversion. This chapter will discuss the implications of such VSG diversity for immune evasion by antigenic variation, and will consider how this expressed diversity can arise, drawing on a growing body of work that has begun to examine the proteins and sequences through which VSG switching is catalyzed. Most studies of trypanosome antigenic variation have focused on T. brucei, the causative agent of human sleeping sickness. Other work has begun to look at antigenic variation in animal-infective trypanosomes, and we will compare the findings that are emerging, as well as consider how antigenic variation relates to the dynamics of host-trypanosome interaction.
Collapse
|
46
|
Saada EA, DeMarco SF, Shimogawa MM, Hill KL. "With a Little Help from My Friends"-Social Motility in Trypanosoma brucei. PLoS Pathog 2015; 11:e1005272. [PMID: 26679190 PMCID: PMC4683075 DOI: 10.1371/journal.ppat.1005272] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Edwin A. Saada
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Stephanie F. DeMarco
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Michelle M. Shimogawa
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Kent L. Hill
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, United States of America
- * E-mail:
| |
Collapse
|
47
|
Domingo-Sananes MR, Szöőr B, Ferguson MAJ, Urbaniak MD, Matthews KR. Molecular control of irreversible bistability during trypanosome developmental commitment. J Cell Biol 2015; 211:455-68. [PMID: 26483558 PMCID: PMC4621835 DOI: 10.1083/jcb.201506114] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/02/2015] [Indexed: 12/15/2022] Open
Abstract
Phosphoproteomic and functional analysis of the developmental progression of Trypanosomes demonstrates that this transition shows bistability, with commitment to differentiation requiring new protein synthesis, and that the protein kinase NRK is a key regulator. The life cycle of Trypanosoma brucei involves developmental transitions that allow survival, proliferation, and transmission of these parasites. One of these, the differentiation of growth-arrested stumpy forms in the mammalian blood into insect-stage procyclic forms, can be induced synchronously in vitro with cis-aconitate. Here, we show that this transition is an irreversible bistable switch, and we map the point of commitment to differentiation after exposure to cis-aconitate. This irreversibility implies that positive feedback mechanisms operate to allow commitment (i.e., the establishment of “memory” of exposure to the differentiation signal). Using the reversible translational inhibitor cycloheximide, we show that this signal memory requires new protein synthesis. We further performed stable isotope labeling by amino acids in cell culture to analyze synchronized parasite populations, establishing the protein and phosphorylation profile of parasites pre- and postcommitment, thereby defining the “commitment proteome.” Functional interrogation of this data set identified Nek-related kinase as the first-discovered protein kinase controlling the initiation of differentiation to procyclic forms.
Collapse
Affiliation(s)
- Maria Rosa Domingo-Sananes
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, Scotland, UK
| | - Balazs Szöőr
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, Scotland, UK
| | - Michael A J Ferguson
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | - Michael D Urbaniak
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YG, England, UK
| | - Keith R Matthews
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, Scotland, UK
| |
Collapse
|
48
|
Bachmaier S, Witztum R, Tsigankov P, Koren R, Boshart M, Zilberstein D. Protein kinase A signaling during bidirectional axenic differentiation in Leishmania. Int J Parasitol 2015; 46:75-82. [PMID: 26460237 DOI: 10.1016/j.ijpara.2015.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 08/14/2015] [Accepted: 09/06/2015] [Indexed: 11/30/2022]
Abstract
Parasitic protozoa of the genus Leishmania are obligatory intracellular parasites that cycle between the phagolysosome of mammalian macrophages, where they proliferate as intracellular amastigotes, and the midgut of female sand flies, where they proliferate as extracellular promastigotes. Shifting between the two environments induces signaling pathway-mediated developmental processes that enable adaptation to both host and vector. Developmentally regulated expression and phosphorylation of protein kinase A subunits in Leishmania and in Trypanosoma brucei point to an involvement of protein kinase A in parasite development. To assess this hypothesis in Leishmania donovani, we determined proteome-wide changes in phosphorylation of the conserved protein kinase A phosphorylation motifs RXXS and RXXT, using a phospho-specific antibody. Rapid dephosphorylation of these motifs was observed upon initiation of promastigote to amastigote differentiation in culture. No phosphorylated sites were detected in axenic amastigotes. To analyse the kinetics of (re)phosphorylation during axenic reverse differentiation from L. donovani amastigotes to promastigotes, we first established a map of this process with morphological and molecular markers. Upon initiation, the parasites rested for 6-12 h before proliferation of an asynchronous population resumed. After early changes in cell shape, the major changes in molecular marker expression and flagella biogenesis occurred between 24 and 33 h after initiation. RXXS/T re-phosphorylation and expression of the regulatory subunit PKAR1 correlated with promastigote maturation, indicating a promastigote-specific function of protein kinase A signaling. This is supported by the localization of PKAR1 to the flagellum, an organelle reduced to a remnant in amastigote forms. We conclude that a significant increase in protein kinase A-mediated phosphorylation is part of the ordered changes that characterise the amastigote to promastigote differentiation.
Collapse
Affiliation(s)
- Sabine Bachmaier
- Ludwig-Maximilian-University Munich (LMU), Faculty of Biology, Genetics, 82152 Martinsried, Germany
| | - Ronit Witztum
- Technion-Israel Institute of Technology, Faculty of Biology, Haifa 32000, Israel
| | - Polina Tsigankov
- Technion-Israel Institute of Technology, Faculty of Biology, Haifa 32000, Israel
| | - Roni Koren
- Technion-Israel Institute of Technology, Faculty of Biology, Haifa 32000, Israel
| | - Michael Boshart
- Ludwig-Maximilian-University Munich (LMU), Faculty of Biology, Genetics, 82152 Martinsried, Germany.
| | - Dan Zilberstein
- Technion-Israel Institute of Technology, Faculty of Biology, Haifa 32000, Israel
| |
Collapse
|
49
|
Krüger T, Engstler M. Flagellar motility in eukaryotic human parasites. Semin Cell Dev Biol 2015; 46:113-27. [DOI: 10.1016/j.semcdb.2015.10.034] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/26/2015] [Accepted: 10/26/2015] [Indexed: 12/31/2022]
|
50
|
Abstract
Mathematical modelling provides an effective way to challenge conventional wisdom about
parasite evolution and investigate why parasites ‘do what they do’ within the host. Models
can reveal when intuition cannot explain observed patterns, when more complicated biology
must be considered, and when experimental and statistical methods are likely to mislead.
We describe how models of within-host infection dynamics can refine experimental design,
and focus on the case study of malaria to highlight how integration between models and
data can guide understanding of parasite fitness in three areas: (1) the adaptive
significance of chronic infections; (2) the potential for tradeoffs between virulence and
transmission; and (3) the implications of within-vector dynamics. We emphasize that models
are often useful when they highlight unexpected patterns in parasite evolution, revealing
instead why intuition yields the wrong answer and what combination of theory and data are
needed to advance understanding.
Collapse
|