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Mendes IC, Dos Reis Bertoldo W, Miranda-Junior AS, Assis AVD, Repolês BM, Ferreira WRR, Chame DF, Souza DDL, Pavani RS, Macedo AM, Franco GR, Serra E, Perdomo V, Menck CFM, da Silva Leandro G, Fragoso SP, Barbosa Elias MCQ, Machado CR. DNA lesions that block transcription induce the death of Trypanosoma cruzi via ATR activation, which is dependent on the presence of R-loops. DNA Repair (Amst) 2024; 141:103726. [PMID: 39096697 DOI: 10.1016/j.dnarep.2024.103726] [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: 11/23/2023] [Revised: 06/25/2024] [Accepted: 07/07/2024] [Indexed: 08/05/2024]
Abstract
Trypanosoma cruzi is the etiological agent of Chagas disease and a peculiar eukaryote with unique biological characteristics. DNA damage can block RNA polymerase, activating transcription-coupled nucleotide excision repair (TC-NER), a DNA repair pathway specialized in lesions that compromise transcription. If transcriptional stress is unresolved, arrested RNA polymerase can activate programmed cell death. Nonetheless, how this parasite modulates these processes is unknown. Here, we demonstrate that T. cruzi cell death after UV irradiation, a genotoxic agent that generates lesions resolved by TC-NER, depends on active transcription and is signaled mainly by an apoptotic-like pathway. Pre-treated parasites with α-amanitin, a selective RNA polymerase II inhibitor, become resistant to such cell death. Similarly, the gamma pre-irradiated cells are more resistant to UV when the transcription processes are absent. The Cockayne Syndrome B protein (CSB) recognizes blocked RNA polymerase and can initiate TC-NER. Curiously, CSB overexpression increases parasites' cell death shortly after UV exposure. On the other hand, at the same time after irradiation, the single-knockout CSB cells show resistance to the same treatment. UV-induced fast death is signalized by the exposition of phosphatidylserine to the outer layer of the membrane, indicating a cell death mainly by an apoptotic-like pathway. Furthermore, such death is suppressed in WT parasites pre-treated with inhibitors of ataxia telangiectasia and Rad3-related (ATR), a key DDR kinase. Signaling for UV radiation death may be related to R-loops since the overexpression of genes associated with the resolution of these structures suppress it. Together, results suggest that transcription blockage triggered by UV radiation activates an ATR-dependent apoptosis-like mechanism in T. cruzi, with the participation of CSB protein in this process.
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Affiliation(s)
- Isabela Cecilia Mendes
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Belo Horizonte, MG 30161-970, Brazil
| | - Willian Dos Reis Bertoldo
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Belo Horizonte, MG 30161-970, Brazil
| | - Adalberto Sales Miranda-Junior
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Belo Horizonte, MG 30161-970, Brazil
| | - Antônio Vinícius de Assis
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Belo Horizonte, MG 30161-970, Brazil
| | - Bruno Marçal Repolês
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Belo Horizonte, MG 30161-970, Brazil
| | - Wesley Roger Rodrigues Ferreira
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Belo Horizonte, MG 30161-970, Brazil
| | - Daniela Ferreira Chame
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Belo Horizonte, MG 30161-970, Brazil
| | - Daniela De Laet Souza
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Belo Horizonte, MG 30161-970, Brazil
| | - Raphael Souza Pavani
- Laboratório Especial de Ciclo Celular, Instituto Butantan, São Paulo, MG, São Paulo, SP 05503-900, Brazil
| | - Andrea Mara Macedo
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Belo Horizonte, MG 30161-970, Brazil
| | - Glória Regina Franco
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Belo Horizonte, MG 30161-970, Brazil
| | - Esteban Serra
- Instituto de Biología Molecular y Celular de Rosario, CONICET, 2000 Rosario, Santa Fe, Argentina; Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, 2000 Rosario, Santa Fe, Argentina
| | - Virginia Perdomo
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, 2000 Rosario, Santa Fe, Argentina
| | - Carlos Frederico Martins Menck
- Departamento de Microbiologia, Instituto de Ciências Biomédicas (ICB), Universidade de São Paulo (USP), São Paulo, SP 05508-900, Brazil
| | - Giovana da Silva Leandro
- Departamento de Microbiologia, Instituto de Ciências Biomédicas (ICB), Universidade de São Paulo (USP), São Paulo, SP 05508-900, Brazil
| | | | | | - Carlos Renato Machado
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Belo Horizonte, MG 30161-970, Brazil.
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Faria J, Briggs EM, Black JA, McCulloch R. Emergence and adaptation of the cellular machinery directing antigenic variation in the African trypanosome. Curr Opin Microbiol 2022; 70:102209. [PMID: 36215868 DOI: 10.1016/j.mib.2022.102209] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/30/2022] [Accepted: 09/04/2022] [Indexed: 01/25/2023]
Abstract
Survival of the African trypanosome within its mammalian hosts, and hence transmission between hosts, relies upon antigenic variation, where stochastic changes in the composition of their protective variant-surface glycoprotein (VSG) coat thwart effective removal of the pathogen by adaptive immunity. Antigenic variation has evolved remarkable mechanistic complexity in Trypanosoma brucei, with switching of the VSG coat executed by either transcriptional or recombination reactions. In the former, a single T. brucei cell selectively transcribes one telomeric VSG transcription site, termed the expression site (ES), from a pool of around 15. Silencing of the active ES and activation of one previously silent ES can lead to a co-ordinated VSG coat switch. Outside the ESs, the T. brucei genome contains an enormous archive of silent VSG genes and pseudogenes, which can be recombined into the ES to execute a coat switch. Most such recombination involves gene conversion, including copying of a complete VSG and more complex reactions where novel 'mosaic' VSGs are formed as patchworks of sequences from several silent (pseudo)genes. Understanding of the cellular machinery that directs transcriptional and recombination VSG switching is growing rapidly and the emerging picture is of the use of proteins, complexes and pathways that are not limited to trypanosomes, but are shared across the wider grouping of kinetoplastids and beyond, suggesting co-option of widely used, core cellular reactions. We will review what is known about the machinery of antigenic variation and discuss if there remains the possibility of trypanosome adaptations, or even trypanosome-specific machineries, that might offer opportunities to impair this crucial parasite-survival process.
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Affiliation(s)
- Joana Faria
- York Biomedical Research Institute, Department of Biology, University of York, United Kingdom.
| | - Emma M Briggs
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom; Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davies Building, 120 University Place, Glasgow G12 8TA, United Kingdom
| | - Jennifer A Black
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil; Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davies Building, 120 University Place, Glasgow G12 8TA, United Kingdom
| | - Richard McCulloch
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davies Building, 120 University Place, Glasgow G12 8TA, United Kingdom.
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3
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da Silva RB, Bertoldo WDR, Naves LL, de Vito FB, Damasceno JD, Tosi LRO, Machado CR, Pedrosa AL. Specific Human ATR and ATM Inhibitors Modulate Single Strand DNA Formation in Leishmania major Exposed to Oxidative Agent. Front Cell Infect Microbiol 2022; 11:802613. [PMID: 35059327 PMCID: PMC8763966 DOI: 10.3389/fcimb.2021.802613] [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: 10/26/2021] [Accepted: 12/02/2021] [Indexed: 12/03/2022] Open
Abstract
Leishmania parasites are the causative agents of a group of neglected tropical diseases known as leishmaniasis. The molecular mechanisms employed by these parasites to adapt to the adverse conditions found in their hosts are not yet completely understood. DNA repair pathways can be used by Leishmania to enable survival in the interior of macrophages, where the parasite is constantly exposed to oxygen reactive species. In higher eukaryotes, DNA repair pathways are coordinated by the central protein kinases ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3 related (ATR). The enzyme Exonuclease-1 (EXO1) plays important roles in DNA replication, repair, and recombination, and it can be regulated by ATM- and ATR-mediated signaling pathways. In this study, the DNA damage response pathways in promastigote forms of L. major were investigated using bioinformatics tools, exposure of lineages to oxidizing agents and radiation damage, treatment of cells with ATM and ATR inhibitors, and flow cytometry analysis. We demonstrated high structural and important residue conservation for the catalytic activity of the putative LmjEXO1. The overexpression of putative LmjEXO1 made L. major cells more susceptible to genotoxic damage, most likely due to the nuclease activity of this enzyme and the occurrence of hyper-resection of DNA strands. These cells could be rescued by the addition of caffeine or a selective ATM inhibitor. In contrast, ATR-specific inhibition made the control cells more susceptible to oxidative damage in an LmjEXO1 overexpression-like manner. We demonstrated that ATR-specific inhibition results in the formation of extended single-stranded DNA, most likely due to EXO1 nucleasic activity. Antagonistically, ATM inhibition prevented single-strand DNA formation, which could explain the survival phenotype of lineages overexpressing LmjEXO1. These results suggest that an ATM homolog in Leishmania could act to promote end resection by putative LmjEXO1, and an ATR homologue could prevent hyper-resection, ensuring adequate repair of the parasite DNA.
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Affiliation(s)
- Raíssa Bernardes da Silva
- Departamento de Bioquímica, Farmacologia e Fisiologia, Instituto de Ciências Biológicas e Naturais, Universidade Federal do Triângulo Mineiro, Uberaba, Brazil
| | - Willian Dos Reis Bertoldo
- Departamento de Bioquímica, Farmacologia e Fisiologia, Instituto de Ciências Biológicas e Naturais, Universidade Federal do Triângulo Mineiro, Uberaba, Brazil.,Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Lucila Langoni Naves
- Departamento de Bioquímica, Farmacologia e Fisiologia, Instituto de Ciências Biológicas e Naturais, Universidade Federal do Triângulo Mineiro, Uberaba, Brazil
| | - Fernanda Bernadelli de Vito
- Departamento de Clínica Médica, Instituto de Ciências da Saúde, Universidade Federal do Triângulo Mineiro, Uberaba, Brazil
| | - Jeziel Dener Damasceno
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Luiz Ricardo Orsini Tosi
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Carlos Renato Machado
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - André Luiz Pedrosa
- Departamento de Bioquímica, Farmacologia e Fisiologia, Instituto de Ciências Biológicas e Naturais, Universidade Federal do Triângulo Mineiro, Uberaba, Brazil
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Silva GLA, Tosi LRO, McCulloch R, Black JA. Unpicking the Roles of DNA Damage Protein Kinases in Trypanosomatids. Front Cell Dev Biol 2021; 9:636615. [PMID: 34422791 PMCID: PMC8377203 DOI: 10.3389/fcell.2021.636615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 07/13/2021] [Indexed: 12/31/2022] Open
Abstract
To preserve genome integrity when faced with DNA lesions, cells activate and coordinate a multitude of DNA repair pathways to ensure timely error correction or tolerance, collectively called the DNA damage response (DDR). These interconnecting damage response pathways are molecular signal relays, with protein kinases (PKs) at the pinnacle. Focused efforts in model eukaryotes have revealed intricate aspects of DNA repair PK function, including how they direct DDR pathways and how repair reactions connect to wider cellular processes, including DNA replication and transcription. The Kinetoplastidae, including many parasites like Trypanosoma spp. and Leishmania spp. (causative agents of debilitating, neglected tropical infections), exhibit peculiarities in several core biological processes, including the predominance of multigenic transcription and the streamlining or repurposing of DNA repair pathways, such as the loss of non-homologous end joining and novel operation of nucleotide excision repair (NER). Very recent studies have implicated ATR and ATM kinases in the DDR of kinetoplastid parasites, whereas DNA-dependent protein kinase (DNA-PKcs) displays uncertain conservation, questioning what functions it fulfills. The wide range of genetic manipulation approaches in these organisms presents an opportunity to investigate DNA repair kinase roles in kinetoplastids and to ask if further kinases are involved. Furthermore, the availability of kinase inhibitory compounds, targeting numerous eukaryotic PKs, could allow us to test the suitability of DNA repair PKs as novel chemotherapeutic targets. Here, we will review recent advances in the study of trypanosomatid DNA repair kinases.
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Affiliation(s)
- Gabriel L A Silva
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom.,Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Luiz R O Tosi
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Richard McCulloch
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Jennifer Ann Black
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom.,Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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5
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4-Chlorophenylthioacetone-derived thiosemicarbazones as potent antitrypanosomal drug candidates: Investigations on the mode of action. Bioorg Chem 2021; 113:105018. [PMID: 34098396 DOI: 10.1016/j.bioorg.2021.105018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 01/26/2023]
Abstract
Chagas disease (ChD), caused by Trypanosoma cruzi, remains a challenge for the medical and scientific fields due to the inefficiency of the therapeutic approaches available for its treatment. Thiosemicarbazones and hydrazones present a wide spectrum of bioactivities and are considered a platform for the design of new anti-T. cruzi drug candidates. Herein, the potential antichagasic activities of [(E)-2-(1-(4-chlorophenylthio)propan-2-ylidene)-hydrazinecarbothioamides] (C1, C3), [(E)-N'-(1-((4-chlorophenyl)thio)propan-2-ylidene)benzohydrazide] (C2), [(E)-2-(1-(4-, and [(E)-2-(1-((4-chlorophenyl)thio)propan-2-ylidene)hydrazinecarboxamide] (C4) were investigated. Macrophages (MOs) from C57BL/6 mice stimulated with C1 and C3, but not with C2 and C4, reduced amastigote replication and trypomastigote release, independent of nitric oxide (NO) and reactive oxygen species production and indoleamine 2,3-dioxygenase activity. C3, but not C1, reduced parasite uptake by MOs and potentiated TNF production. In cardiomyocytes, C3 reduced trypomastigote release independently of NO, TNF, and IL-6 production. C1 and C3 were non-toxic to the host cells. A reduction of parasite release was found during infection of MOs with trypomastigotes pre-incubated with C1 or C3 and MOs pre-stimulated with compounds before infection. Moreover, C1 and C3 acted directly on trypomastigotes, killing them faster than Benznidazole, and inhibited T. cruzi proliferation at various stages of its intracellular cycle. Mechanistically, C1 and C3 inhibit parasite duplication, and this process cannot be reversed by inhibiting the DNA damage response. In vivo, C1 and C3 attenuated parasitemia in T. cruzi-infected mice. Moreover, C3 loaded in a lipid nanocarrier system (nanoemulsion) maintained anti-T. cruzi activity in vivo. Collectively, these data suggest that C1 and C3 are candidates for the treatment of ChD and present activity in both the host and parasite cells.
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6
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Marin PA, Obonaga R, Pavani RS, da Silva MS, de Araujo CB, Lima AA, Avila CC, Cestari I, Machado CR, Elias MC. ATR Kinase Is a Crucial Player Mediating the DNA Damage Response in Trypanosoma brucei. Front Cell Dev Biol 2020; 8:602956. [PMID: 33415107 PMCID: PMC7783291 DOI: 10.3389/fcell.2020.602956] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/02/2020] [Indexed: 12/26/2022] Open
Abstract
DNA double-strand breaks (DSBs) are among the most deleterious lesions that threaten genome integrity. To address DSBs, eukaryotic cells of model organisms have evolved a complex network of cellular pathways that are able to detect DNA damage, activate a checkpoint response to delay cell cycle progression, recruit the proper repair machinery, and resume the cell cycle once the DNA damage is repaired. Cell cycle checkpoints are primarily regulated by the apical kinases ATR and ATM, which are conserved throughout the eukaryotic kingdom. Trypanosoma brucei is a divergent pathogenic protozoan parasite that causes human African trypanosomiasis (HAT), a neglected disease that can be fatal when left untreated. The proper signaling and accuracy of DNA repair is fundamental to T. brucei not only to ensure parasite survival after genotoxic stress but also because DSBs are involved in the process of generating antigenic variations used by this parasite to evade the host immune system. DSBs trigger a strong DNA damage response and efficient repair process in T. brucei, but it is unclear how these processes are coordinated. Here, by knocking down ATR in T. brucei using two different approaches (conditional RNAi and an ATR inhibitor), we show that ATR is required to mediate intra-S and partial G1/S checkpoint responses. ATR is also involved in replication fork stalling, is critical for H2A histone phosphorylation in a small group of cells and is necessary for the recruitment and upregulation of the HR-mediated DNA repair protein RAD51 after ionizing radiation (IR) induces DSBs. In summary, this work shows that apical ATR kinase plays a central role in signal transduction and is critical for orchestrating the DNA damage response in T. brucei.
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Affiliation(s)
- Paula Andrea Marin
- Laboratory of Cell Cycle (LCC), Center of Toxins, Immune Response and Cell Signaling (CETICs), Butantan Institute, São Paulo, Brazil
| | - Ricardo Obonaga
- Laboratory of Cell Cycle (LCC), Center of Toxins, Immune Response and Cell Signaling (CETICs), Butantan Institute, São Paulo, Brazil
| | - Raphael Souza Pavani
- Laboratory of Cell Cycle (LCC), Center of Toxins, Immune Response and Cell Signaling (CETICs), Butantan Institute, São Paulo, Brazil
| | - Marcelo Santos da Silva
- Laboratory of Cell Cycle (LCC), Center of Toxins, Immune Response and Cell Signaling (CETICs), Butantan Institute, São Paulo, Brazil
| | - Christiane Bezerra de Araujo
- Laboratory of Cell Cycle (LCC), Center of Toxins, Immune Response and Cell Signaling (CETICs), Butantan Institute, São Paulo, Brazil
| | - André Arruda Lima
- Laboratory of Cell Cycle (LCC), Center of Toxins, Immune Response and Cell Signaling (CETICs), Butantan Institute, São Paulo, Brazil
| | - Carla Cristi Avila
- Laboratory of Cell Cycle (LCC), Center of Toxins, Immune Response and Cell Signaling (CETICs), Butantan Institute, São Paulo, Brazil
| | - Igor Cestari
- Institute of Parasitology, McGill University, Montreal, QC, Canada
- Division of Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Carlos Renato Machado
- Biochemical and Immunology Department, Institute of Biomedical Science, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Maria Carolina Elias
- Laboratory of Cell Cycle (LCC), Center of Toxins, Immune Response and Cell Signaling (CETICs), Butantan Institute, São Paulo, Brazil
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Grazielle-Silva V, Zeb TF, Burchmore R, Machado CR, McCulloch R, Teixeira SMR. Trypanosoma brucei and Trypanosoma cruzi DNA Mismatch Repair Proteins Act Differently in the Response to DNA Damage Caused by Oxidative Stress. Front Cell Infect Microbiol 2020; 10:154. [PMID: 32373549 PMCID: PMC7176904 DOI: 10.3389/fcimb.2020.00154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 03/23/2020] [Indexed: 01/05/2023] Open
Abstract
MSH2, associated with MSH3 or MSH6, is a central component of the eukaryotic DNA Mismatch Repair (MMR) pathway responsible for the recognition and correction of base mismatches that occur during DNA replication and recombination. Previous studies have shown that MSH2 plays an additional DNA repair role in response to oxidative damage in Trypanosoma cruzi and Trypanosoma brucei. By performing co-immunoprecipitation followed by mass spectrometry with parasites expressing tagged proteins, we confirmed that the parasites' MSH2 forms complexes with MSH3 and MSH6. To investigate the involvement of these two other MMR components in the oxidative stress response, we generated knockout mutants of MSH6 and MSH3 in T. brucei bloodstream forms and MSH6 mutants in T. cruzi epimastigotes. Differently from the phenotype observed with T. cruzi MSH2 knockout epimastigotes, loss of one or two alleles of T. cruzi msh6 resulted in increased susceptibility to H2O2 exposure, besides impaired MMR. In contrast, T. brucei msh6 or msh3 null mutants displayed increased tolerance to MNNG treatment, indicating that MMR is affected, but no difference in the response to H2O2 treatment when compared to wild type cells. Taken together, our results suggest that, while T. cruzi MSH6 and MSH2 are involved with the oxidative stress response in addition to their role as components of the MMR, the DNA repair pathway that deals with oxidative stress damage operates differently in T. brucei.
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Affiliation(s)
- Viviane Grazielle-Silva
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.,The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Tehseen Fatima Zeb
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Richard Burchmore
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Carlos Renato Machado
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Richard McCulloch
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Santuza M R Teixeira
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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8
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Nunes VS, Moretti NS, da Silva MS, Elias MC, Janzen CJ, Schenkman S. Trimethylation of histone H3K76 by Dot1B enhances cell cycle progression after mitosis in Trypanosoma cruzi. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118694. [PMID: 32151656 DOI: 10.1016/j.bbamcr.2020.118694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 03/03/2020] [Accepted: 03/05/2020] [Indexed: 12/11/2022]
Abstract
Dot1 enzymes are histone methyltransferases that mono-, di- and trimethylate lysine 79 of histone H3 to affect several nuclear processes. The functions of these different methylation states are still largely unknown. Trypanosomes, which are flagellated protozoa that cause several parasitic diseases, have two Dot1 homologues. Dot1A catalyzes the mono- and dimethylation of lysine 76 during late G2 and mitosis, and Dot1B catalyzes trimethylation, which is a modification found in all stages of the cell cycle. Here, we generated Trypanosoma cruzi lines lacking Dot1B. Deletion of one allele resulted in parasites with increased levels of mono- and dimethylation and a reduction in H3K76me3. In the full knockout (DKO), no trimethylation was observed. Both the DKO and the single knockout (SKO) showed aberrant morphology and decreased growth due to cell cycle arrest after G2. This phenotype could be rescued by caffeine in the DKO, as caffeine is a checkpoint inhibitor of the cell cycle. The knockouts also phosphorylated γH2A without producing extensive DNA breaks, and Dot1B-depleted cells were more susceptible to general checkpoint kinase inhibitors, suggesting that a lack of H3K76 trimethylation prevents the initiation and/or completion of cytokinesis.
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Affiliation(s)
- Vinicius Santana Nunes
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, 04032-039 São Paulo, SP, Brazil; Centro de Ensino, Pesquisa e Inovação, Hospital Evangélico de Vila Velha, 29118-060 Vila Velha, ES, Brazil
| | - Nilmar Silvio Moretti
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, 04032-039 São Paulo, SP, Brazil
| | | | - Maria Carolina Elias
- Laboratório Especial de Ciclo Celular, Instituto Butantan, São Paulo, SP, Brazil
| | - Christian J Janzen
- Department of Cell & Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Sergio Schenkman
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, 04032-039 São Paulo, SP, Brazil.
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