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Jung KW, Kwon S, Jung JH, Lim S, Bahn YS. Functional Characterization of DNA N-Glycosylase Ogg1 and Ntg1 in DNA Damage Stress of Cryptococcus neoformans. J Microbiol 2023; 61:981-992. [PMID: 38055144 DOI: 10.1007/s12275-023-00092-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 10/31/2023] [Indexed: 12/07/2023]
Abstract
Reactive oxygen species induce DNA strand breaks and DNA oxidation. DNA oxidation leads to DNA mismatches, resulting in mutations in the genome if not properly repaired. Homologous recombination (HR) and non-homologous end-joining (NHEJ) are required for DNA strand breaks, whereas the base excision repair system mainly repairs oxidized DNAs, such as 8-oxoguanine and thymine glycol, by cleaving the glycosidic bond, inserting correct nucleotides, and sealing the gap. Our previous studies revealed that the Rad53-Bdr1 pathway mainly controls DNA strand breaks through the regulation of HR- and NHEJ-related genes. However, the functional roles of genes involved in the base excision repair system remain elusive in Cryptococcus neoformans. In the present study, we identified OGG1 and NTG1 genes in the base excision repair system of C. neoformans, which are involved in DNA oxidation repair. The expression of OGG1 was induced in a Hog1-dependent manner under oxidative stress. On the other hand, the expression of NTG1 was strongly induced by DNA damage stress in a Rad53-independent manner. We demonstrated that the deletion of NTG1, but not OGG1, resulted in elevated susceptibility to DNA damage agents and oxidative stress inducers. Notably, the ntg1Δ mutant showed growth defects upon antifungal drug treatment. Although deletion of OGG1 or NTG1 did not increase mutation rates, the mutation profile of each ogg1Δ and ntg1Δ mutant was different from that of the wild-type strain. Taken together, we found that DNA N-glycosylase Ntg1 is required for oxidative DNA damage stress and antifungal drug resistance in C. neoformans.
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Affiliation(s)
- Kwang-Woo Jung
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea.
| | - Sunhak Kwon
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Jong-Hyun Jung
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea
| | - Sangyong Lim
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea
- Department of Radiation Science, University of Science and Technology, Daejeon, 34113, Republic of Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
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2
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Pyrih J, Hammond M, Alves A, Dean S, Sunter JD, Wheeler RJ, Gull K, Lukeš J. Comprehensive sub-mitochondrial protein map of the parasitic protist Trypanosoma brucei defines critical features of organellar biology. Cell Rep 2023; 42:113083. [PMID: 37669165 DOI: 10.1016/j.celrep.2023.113083] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 06/30/2023] [Accepted: 08/17/2023] [Indexed: 09/07/2023] Open
Abstract
We have generated a high-confidence mitochondrial proteome (MitoTag) of the Trypanosoma brucei procyclic stage containing 1,239 proteins. For 337 of these, a mitochondrial localization had not been described before. We use the TrypTag dataset as a foundation and take advantage of the properties of the fluorescent protein tag that causes aberrant but fortuitous accumulation of tagged matrix and inner membrane proteins near the kinetoplast (mitochondrial DNA). Combined with transmembrane domain predictions, this characteristic allowed categorization of 1,053 proteins into mitochondrial sub-compartments, the detection of unique matrix-localized fucose and methionine synthesis, and the identification of new kinetoplast proteins, which showed kinetoplast-linked pyrimidine synthesis. Moreover, disruption of targeting signals by tagging allowed mapping of the mode of protein targeting to these sub-compartments, identifying a set of C-tail anchored outer mitochondrial membrane proteins and mitochondrial carriers likely employing multiple target peptides. This dataset represents a comprehensive, updated mapping of the mitochondrion.
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Affiliation(s)
- Jan Pyrih
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Department of Biochemistry, University of Cambridge, Cambridge, UK; Faculty of Science, University of Ostrava, Ostrava, Czech Republic.
| | - Michael Hammond
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
| | | | - Samuel Dean
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | | | - Richard John Wheeler
- Peter Medawar Building for Pathogen Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic.
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3
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Gonçalves CS, Catta-Preta CMC, Repolês B, Mottram JC, De Souza W, Machado CR, Motta MCM. Importance of Angomonas deanei KAP4 for kDNA arrangement, cell division and maintenance of the host-bacterium relationship. Sci Rep 2021; 11:9210. [PMID: 33911164 PMCID: PMC8080567 DOI: 10.1038/s41598-021-88685-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 04/13/2021] [Indexed: 11/29/2022] Open
Abstract
Angomonas deanei coevolves in a mutualistic relationship with a symbiotic bacterium that divides in synchronicity with other host cell structures. Trypanosomatid mitochondrial DNA is contained in the kinetoplast and is composed of thousands of interlocked DNA circles (kDNA). The arrangement of kDNA is related to the presence of histone-like proteins, known as KAPs (kinetoplast-associated proteins), that neutralize the negatively charged kDNA, thereby affecting the activity of mitochondrial enzymes involved in replication, transcription and repair. In this study, CRISPR-Cas9 was used to delete both alleles of the A. deanei KAP4 gene. Gene-deficient mutants exhibited high compaction of the kDNA network and displayed atypical phenotypes, such as the appearance of a filamentous symbionts, cells containing two nuclei and one kinetoplast, and division blocks. Treatment with cisplatin and UV showed that Δkap4 null mutants were not more sensitive to DNA damage and repair than wild-type cells. Notably, lesions caused by these genotoxic agents in the mitochondrial DNA could be repaired, suggesting that the kDNA in the kinetoplast of trypanosomatids has unique repair mechanisms. Taken together, our data indicate that although KAP4 is not an essential protein, it plays important roles in kDNA arrangement and replication, as well as in the maintenance of symbiosis.
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Affiliation(s)
- Camila Silva Gonçalves
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, IBCCF, CCS, UFRJ, Cidade Universitária, Rio de Janeiro, RJ, CEP 21941-590, Brazil
- Centro Nacional de Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | | | - Bruno Repolês
- Laboratório de Genética Bioquímica, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Jeremy C Mottram
- Department of Biology, York Biomedical Research Institute, University of York, Wentworth Way, Heslington, York, YO10 5DD, UK
| | - Wanderley De Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, IBCCF, CCS, UFRJ, Cidade Universitária, Rio de Janeiro, RJ, CEP 21941-590, Brazil
- Centro Nacional de Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Carlos Renato Machado
- Laboratório de Genética Bioquímica, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
| | - Maria Cristina M Motta
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, IBCCF, CCS, UFRJ, Cidade Universitária, Rio de Janeiro, RJ, CEP 21941-590, Brazil.
- Centro Nacional de Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil.
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Characterization and functional analysis of the proteins Prohibitin 1 and 2 in Trypanosoma cruzi. PLoS Negl Trop Dis 2021; 15:e0009322. [PMID: 33830991 PMCID: PMC8057595 DOI: 10.1371/journal.pntd.0009322] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 04/20/2021] [Accepted: 03/23/2021] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Chagas disease is the third most important neglected tropical disease. There is no vaccine available, and only two drugs are generally prescribed for the treatment, both of which with a wide range of side effects. Our study of T. cruzi PHBs revealed a pleiotropic function in different stages of the parasite, participating actively in the transformation of the non-infective replicative epimastigote form into metacyclic trypomastigotes and also in the multiplication of intracellular amastigotes. METHODOLOGY/PRINCIPAL FINDINGS To obtain and confirm our results, we applied several tools and techniques such as electron microscopy, immuno-electron microscopy, bioinformatics analysis and molecular biology. We transfected T. cruzi clones with the PHB genes, in order to overexpress the proteins and performed a CRISPR/Cas9 disruption to obtain partially silenced PHB1 parasites or completely silenced PHB2 parasites. The function of these proteins was also studied in the biology of the parasite, specifically in the transformation rate from non-infective forms to the metacyclic infective forms, and in their capacity of intracellular multiplication. CONCLUSION/SIGNIFICANCE This research expands our understanding of the functions of PHBs in the life cycle of the parasite. It also highlights the protective role of prohibitins against ROS and reveals that the absence of PHB2 has a lethal effect on the parasite, a fact that could support the consideration of this protein as a possible target for therapeutic action.
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Maldonado E, Rojas DA, Morales S, Miralles V, Solari A. Dual and Opposite Roles of Reactive Oxygen Species (ROS) in Chagas Disease: Beneficial on the Pathogen and Harmful on the Host. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:8867701. [PMID: 33376582 PMCID: PMC7746463 DOI: 10.1155/2020/8867701] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/22/2020] [Accepted: 11/25/2020] [Indexed: 11/18/2022]
Abstract
Chagas disease is a neglected tropical disease, which affects an estimate of 6-7 million people worldwide. Chagas disease is caused by Trypanosoma cruzi, which is a eukaryotic flagellate unicellular organism. At the primary infection sites, these parasites are phagocytized by macrophages, which produce reactive oxygen species (ROS) in response to the infection with T. cruzi. The ROS produce damage to the host tissues; however, macrophage-produced ROS is also used as a signal for T. cruzi proliferation. At the later stages of infection, mitochondrial ROS is produced by the infected cardiomyocytes that contribute to the oxidative damage, which persists at the chronic stage of the disease. The oxidative damage leads to a functional impairment of the heart. In this review article, we will discuss the mechanisms by which T. cruzi is able to deal with the oxidative stress and how this helps the parasite growth at the acute phase of infection and how the oxidative stress affects the cardiomyopathy at the chronic stage of the Chagas disease. We will describe the mechanisms used by the parasite to deal with ROS and reactive nitrogen species (RNS) through the trypanothione and the mechanisms used to repair the damaged DNA. Also, a description of the events produced by ROS at the acute and chronic stages of the disease is presented. Lastly, we discuss the benefits of ROS for T. cruzi growth and proliferation and the possible mechanisms involved in this phenomenon. Hypothesis is put forward to explain the molecular mechanisms by which ROS triggers parasite growth and proliferation and how ROS is able to produce a long persisting damage on cardiomyocytes even in the absence of the parasite.
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Affiliation(s)
- Edio Maldonado
- Programa Biología Celular y Molecular, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Diego A. Rojas
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Sebastian Morales
- Programa Biología Celular y Molecular, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Vicente Miralles
- Departamento de Bioquímica y Biología Molecular, Universidad de Valencia, Valencia, Spain
| | - Aldo Solari
- Programa Biología Celular y Molecular, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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Marco Antônio Salgado Martins T, de Figueiredo Peloso E, Costa-Silva HM, Rajão MA, Van Houten B, Machado CR, Ramos Gadelha F. Mitochondrial behavior during nuclear and mitochondrial DNA repair in Trypanosoma cruzi epimastigotes. Exp Parasitol 2020; 219:108016. [PMID: 33035543 DOI: 10.1016/j.exppara.2020.108016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/30/2020] [Accepted: 10/05/2020] [Indexed: 12/12/2022]
Abstract
Different genotoxic agents can lead to DNA single- and double-strand breaks, base modification and oxidation. As most living organisms, Trypanosoma cruzi is subjected to oxidative stress during its life cycle; thus, DNA repair is essential for parasite survival and establishment of infection. The mitochondrion plays important roles beyond the production of ATP. For example, it is a source of signaling molecules, such as the superoxide anion and H2O2. Since T. cruzi has only one mitochondrion, the integrity of this organelle is pivotal for parasite viability. H2O2 and methyl methanesulfonate cause DNA lesions in T. cruzi that are repaired by different DNA repair pathways. Herein, we evaluate mitochondrial involvement during the repair of nuclear and mitochondrial DNA in T. cruzi epimastigotes incubated with these two genotoxic agents under conditions that induce repairable DNA damage. Overall, in both treatments, an increase in oxygen consumption rates and in mitochondrial H2O2 release was observed, as well as maintenance of ATP levels compared to control. Interestingly, these changes coincided with DNA repair kinetics, suggesting the importance of the mitochondrion for this energy-consuming process.
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Affiliation(s)
| | | | | | - Matheus Andrade Rajão
- Departamento de Bioquímica e Imunologia, ICB - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Bennet Van Houten
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine and the University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, PA, United States
| | - Carlos Renato Machado
- Departamento de Bioquímica e Imunologia, ICB - UFMG, Belo Horizonte, Minas Gerais, Brazil
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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.
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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)
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8
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Rose E, Carvalho JL, Hecht M. Mechanisms of DNA repair in Trypanosoma cruzi: What do we know so far? DNA Repair (Amst) 2020; 91-92:102873. [PMID: 32505694 DOI: 10.1016/j.dnarep.2020.102873] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/27/2020] [Accepted: 05/22/2020] [Indexed: 12/13/2022]
Abstract
Trypanosoma cruzi is the etiological agent of Chagas Disease, which affects 6-7 million people worldwide. Since the early stages of infection and throughout its life cycle, the parasite is exposed to several genotoxic agents. Furthermore, DNA damage is also part of the mechanism of action of at least a few trypanocidal drugs, including Benznidazole. Thus, it is paramount for the parasite to count on an efficient DNA repair machinery to guarantee genome integrity and survival. The present work provides an up-to-date review of both the conserved and peculiar DNA repair mechanisms described in T. cruzi against oxidative stress, ultraviolet and ionizing radiation, DNA adduct-inducing agents, and Benznidazole. The comprehension of the DNA repair mechanisms of the parasite may shed light on the parasite evolution and possibly pave the way for the development of novel and more effective trypanocidal drugs.
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Affiliation(s)
- Ester Rose
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasília, Brasília, Brazil.
| | - Juliana Lott Carvalho
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasília, Brasília, Brazil; Genomic Sciences and Biotechnology Program, Catholic University of Brasília, Brasília, Brazil
| | - Mariana Hecht
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasília, Brasília, Brazil
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Tunes LG, Morato RE, Garcia A, Schmitz V, Steindel M, Corrêa-Junior JD, Dos Santos HF, Frézard F, de Almeida MV, Silva H, Moretti NS, de Barros ALB, do Monte-Neto RL. Preclinical Gold Complexes as Oral Drug Candidates to Treat Leishmaniasis Are Potent Trypanothione Reductase Inhibitors. ACS Infect Dis 2020; 6:1121-1139. [PMID: 32283915 DOI: 10.1021/acsinfecdis.9b00505] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The drugs currently used to treat leishmaniases have limitations concerning cost, efficacy, and safety, making the search for new therapeutic approaches urgent. We found that the gold(I)-derived complexes were active against L. infantum and L. braziliensis intracellular amastigotes with IC50 values ranging from 0.5 to 5.5 μM. All gold(I) complexes were potent inhibitors of trypanothione reductase (TR), with enzyme IC50 values ranging from 1 to 7.8 μM. Triethylphosphine-derived complexes enhanced reactive oxygen species (ROS) production and decreased mitochondrial respiration after 2 h of exposure, indicating that gold(I) complexes cause oxidative stress by direct ROS production, by causing mitochondrial damage or by impairing TR activity and thus accumulating ROS. There was no cross-resistance to antimony; in fact, SbR (antimony-resistant mutants) strains were hypersensitive to some of the complexes. BALB/c mice infected with luciferase-expressing L. braziliensis or L. amazonensis and treated orally with 12.5 mg/kg/day of AdT Et (3) or AdO Et (4) presented reduced lesion size and parasite burden, as revealed by bioimaging. The combination of (3) and miltefosine allowed for a 50% reduction in miltefosine treatment time. Complexes 3 and 4 presented favorable pharmacokinetic and toxicity profiles that encourage further drug development studies. Gold(I) complexes are promising antileishmanial agents, with a potential for therapeutic use, including in leishmaniasis caused by antimony-resistant parasites.
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Affiliation(s)
- Luiza G. Tunes
- Instituto René Rachou/Fiocruz Minas−Fundação Oswaldo Cruz, Belo Horizonte 30190-009, Brasil
| | - Roberta E. Morato
- Instituto René Rachou/Fiocruz Minas−Fundação Oswaldo Cruz, Belo Horizonte 30190-009, Brasil
| | - Adriana Garcia
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, Juiz de Fora 36036-900, Brasil
| | - Vinicius Schmitz
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, Juiz de Fora 36036-900, Brasil
| | - Mario Steindel
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de Santa Catarina, Florianópolis 88040-900, Brasil
| | - José D. Corrêa-Junior
- Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brasil
| | - Hélio F. Dos Santos
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, Juiz de Fora 36036-900, Brasil
| | - Frédéric Frézard
- Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brasil
| | - Mauro V. de Almeida
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, Juiz de Fora 36036-900, Brasil
| | - Heveline Silva
- Departamento de Química, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brasil
| | - Nilmar S. Moretti
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo 04023-062, Brasil
| | - André L. B. de Barros
- Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brasil
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Repolês BM, Machado CR, Florentino PTV. DNA lesions and repair in trypanosomatids infection. Genet Mol Biol 2020; 43:e20190163. [PMID: 32236391 PMCID: PMC7197992 DOI: 10.1590/1678-4685-gmb-2019-0163] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 10/21/2019] [Indexed: 12/22/2022] Open
Abstract
Pathological processes such as bacterial, viral and parasitic infections can generate a plethora of responses such as, but not restricted to, oxidative stress that can be harmful to the host and the pathogen. This stress occurs when there is an imbalance between reactive oxygen species produced and antioxidant factors produced in response to the infection. This imbalance can lead to DNA lesions in both infected cells as well as in the pathogen. The effects of the host response on the parasite lead to several kinds of DNA damage, causing alterations in the parasite's metabolism; the reaction and sensitivity of the parasite to these responses are related to the DNA metabolism and life cycle of each parasite. The present review will discuss the survival strategies developed by host cells and Trypanosoma cruzi, focusing on the DNA repair mechanisms of these organisms throughout infection including the relationship between DNA damage, stress response features, and the unique characteristics of these diseases.
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Affiliation(s)
- Bruno M Repolês
- Universidade Federal de Minas Gerais, Departamento de Bioquímica e Imunologia, Belo Horizonte MG, Brazil
| | - Carlos Renato Machado
- Universidade Federal de Minas Gerais, Departamento de Bioquímica e Imunologia, Belo Horizonte MG, Brazil
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11
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RB1 Deletion in Retinoblastoma Protein Pathway-Disrupted Cells Results in DNA Damage and Cancer Progression. Mol Cell Biol 2019; 39:MCB.00105-19. [PMID: 31138663 DOI: 10.1128/mcb.00105-19] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/20/2019] [Indexed: 12/12/2022] Open
Abstract
Proliferative control in cancer cells is frequently disrupted by mutations in the retinoblastoma protein (RB) pathway. Intriguingly, RB1 mutations can arise late in tumorigenesis in cancer cells whose RB pathway is already compromised by another mutation. In this study, we present evidence for increased DNA damage and instability in cancer cells with RB pathway defects when RB1 mutations are induced. We generated isogenic RB1 mutant genotypes with CRISPR/Cas9 in a number of cell lines. Cells with even one mutant copy of RB1 have increased basal levels of DNA damage and increased mitotic errors. Elevated levels of reactive oxygen species as well as impaired homologous recombination repair underlie this DNA damage. When xenografted into immunocompromised mice, RB1 mutant cells exhibit an elevated propensity to seed new tumors in recipient lungs. This study offers evidence that late-arising RB1 mutations can facilitate genome instability and cancer progression that are beyond the preexisting proliferative control deficit.
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12
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Azuara-Liceaga E, Betanzos A, Cardona-Felix CS, Castañeda-Ortiz EJ, Cárdenas H, Cárdenas-Guerra RE, Pastor-Palacios G, García-Rivera G, Hernández-Álvarez D, Trasviña-Arenas CH, Diaz-Quezada C, Orozco E, Brieba LG. The Sole DNA Ligase in Entamoeba histolytica Is a High-Fidelity DNA Ligase Involved in DNA Damage Repair. Front Cell Infect Microbiol 2018; 8:214. [PMID: 30050869 PMCID: PMC6052137 DOI: 10.3389/fcimb.2018.00214] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/07/2018] [Indexed: 01/03/2023] Open
Abstract
The protozoan parasite Entamoeba histolytica is exposed to reactive oxygen and nitric oxide species that have the potential to damage its genome. E. histolytica harbors enzymes involved in DNA repair pathways like Base and Nucleotide Excision Repair. The majority of DNA repairs pathways converge in their final step in which a DNA ligase seals the DNA nicks. In contrast to other eukaryotes, the genome of E. histolytica encodes only one DNA ligase (EhDNAligI), suggesting that this ligase is involved in both DNA replication and DNA repair. Therefore, the aim of this work was to characterize EhDNAligI, its ligation fidelity and its ability to ligate opposite DNA mismatches and oxidative DNA lesions, and to study its expression changes and localization during and after recovery from UV and H2O2 treatment. We found that EhDNAligI is a high-fidelity DNA ligase on canonical substrates and is able to discriminate erroneous base-pairing opposite DNA lesions. EhDNAligI expression decreases after DNA damage induced by UV and H2O2 treatments, but it was upregulated during recovery time. Upon oxidative DNA damage, EhDNAligI relocates into the nucleus where it co-localizes with EhPCNA and the 8-oxoG adduct. The appearance and disappearance of 8-oxoG during and after both treatments suggest that DNA damaged was efficiently repaired because the mainly NER and BER components are expressed in this parasite and some of them were modulated after DNA insults. All these data disclose the relevance of EhDNAligI as a specialized and unique ligase in E. histolytica that may be involved in DNA repair of the 8-oxoG lesions.
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Affiliation(s)
- Elisa Azuara-Liceaga
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City, Mexico,*Correspondence: Elisa Azuara-Liceaga
| | - Abigail Betanzos
- Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico,Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Cesar S. Cardona-Felix
- Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico,Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados, Irapuato, Mexico
| | | | - Helios Cárdenas
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City, Mexico
| | - Rosa E. Cárdenas-Guerra
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City, Mexico
| | - Guillermo Pastor-Palacios
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados, Irapuato, Mexico
| | - Guillermina García-Rivera
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - David Hernández-Álvarez
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City, Mexico
| | - Carlos H. Trasviña-Arenas
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados, Irapuato, Mexico
| | - Corina Diaz-Quezada
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados, Irapuato, Mexico
| | - Esther Orozco
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Luis G. Brieba
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados, Irapuato, Mexico,Luis G. Brieba
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13
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Valenzuela L, Sepúlveda S, Ponce I, Galanti N, Cabrera G. The overexpression of TcAP1 endonuclease confers resistance to infective Trypanosoma cruzi trypomastigotes against oxidative DNA damage. J Cell Biochem 2018; 119:5985-5995. [PMID: 29575156 DOI: 10.1002/jcb.26795] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/20/2018] [Indexed: 01/22/2023]
Abstract
Trypanosoma cruzi, the causative agent of Chagas' disease survives to DNA damage generated by ROS/RNS inside to their different hosts. In recent eukaryotes, oxidative DNA damage is repaired mainly by the Base Excision Repair (BER) pathway, being essential the apurinic/apyrimidinic endonuclease activity. Using a pTREX-gfp vector, the nucleotide sequence that encodes T. cruzi AP endonuclease TcAP1 (orthologue of human APE1) and a putative TcAP1 dominant negative (TcAP1DN), were transfectedand expressed in T. cruzi epimastigotes. TcAP1-GFP and TcAP1DN-GFP were expressed in those modified epimastigotes and found in the parasite nucleus. The endonucleases were purified under native conditions and the AP endonuclease activity was evaluated. While TcAP1 presents the expected AP endonuclease activity TcAP1DN does not. Moreover, TcAP1DN partially inhibits in vitro TcAP1 enzymatic activity. Transfected epimastigotes expressing TcAP1-GFP and TcAP1DN-GFP were differentiated to infective trypomastigotes. The infective parasites maintained both proteins (TcAP1-GFP and TcAP1DN-GFP) in the nucleus. The overexpression of TcAP1-GFP in epimastigotes and trypomastigotes increases the viability of both parasite forms when exposed to oxidative stress while the expression of TcAP1DN-GFP did not show any in vivo inhibitory effect, suggesting that endogenous TcAP1 constitutive expression overcomes the TcAP1DN inhibitory activity. Our results show that TcAP1 is important for trypomastigote survival under oxidative conditions similar to those found in infected mammalian cells, then increasing its permanence in the infected cells and the possibility of development of Chagas disease.
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Affiliation(s)
- Lucía Valenzuela
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Programa de Doctorado en Ciencias Silvoagropecuarias y Veterinarias, Universidad de Chile, Santiago, Chile
| | - Soía Sepúlveda
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Iván Ponce
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Norbel Galanti
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Gonzalo Cabrera
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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14
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Oxidative Stress-Mediated Overexpression of Uracil DNA Glycosylase in Leishmania donovani Confers Tolerance against Antileishmanial Drugs. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:4074357. [PMID: 29636843 PMCID: PMC5845521 DOI: 10.1155/2018/4074357] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 12/01/2017] [Accepted: 12/19/2017] [Indexed: 01/09/2023]
Abstract
Leishmania donovani is an intracellular protozoan parasite that causes endemic tropical disease visceral leishmaniasis (VL). Present drugs used against this fatal disease are facing resistance and toxicity issues. Survival of leishmania inside the host cells depends on the parasite's capacity to cope up with highly oxidative environment. Base excision repair (BER) pathway in L. donovani remains unexplored. We studied uracil DNA glycosylase (UNG), the key enzyme involved in BER pathway, and found that the glycosylase activity of recombinant LdUNG (Leishmania donovani UNG) expressed in E. coli is in sync with the activity of the parasite lysate under different reaction conditions. Overexpression of UNG in the parasite enhances its tolerance towards various agents which produce reactive oxygen species (ROS) and shows a higher infectivity in macrophages. Surprisingly, exposure of parasite to amphotericin B and sodium antimony gluconate upregulates the expression of UNG. Further, we found that the drug resistant parasites isolated from VL patients show higher expression of UNG. Mechanisms of action of some currently used drugs include accumulation of ROS. Our findings strongly suggest that targeting LdUNG would be an attractive therapeutic strategy as well as potential measure to tackle the problem of drug resistance in the treatment of leishmaniasis.
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15
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Kunrath-Lima M, Repolês BM, Alves CL, Furtado C, Rajão MA, Macedo AM, Franco GR, Pena SDJ, Valenzuela L, Wisnovsky S, Kelley SO, Galanti N, Cabrera G, Machado CR. Characterization of Trypanosoma cruzi MutY DNA glycosylase ortholog and its role in oxidative stress response. INFECTION GENETICS AND EVOLUTION 2017; 55:332-342. [PMID: 28970112 DOI: 10.1016/j.meegid.2017.09.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 09/25/2017] [Accepted: 09/26/2017] [Indexed: 12/11/2022]
Abstract
Trypanosoma cruzi is a protozoan parasite and the causative agent of Chagas disease. Like most living organisms, it is susceptible to oxidative stress, and must adapt to distinct environments. Hence, DNA repair is essential for its survival and the persistence of infection. Therefore, we studied whether T. cruzi has a homolog counterpart of the MutY enzyme (TcMYH), important in the DNA Base Excision Repair (BER) mechanism. Analysis of T. cruzi genome database showed that this parasite has a putative MutY DNA glycosylase sequence. We performed heterologous complementation assays using this genomic sequence. TcMYH complemented the Escherichia coli MutY- strain, reducing the mutation rate to a level similar to wild type. In in vitro assays, TcMYH was able to remove an adenine that was opposite to 8-oxoguanine. We have also constructed a T. cruzi lineage that overexpresses MYH. Although in standard conditions this lineage has similar growth to control cells, the overexpressor is more sensitive to hydrogen peroxide and glucose oxidase than the control, probably due to accumulation of AP sites in its DNA. Localization experiments with GFP-fused TcMYH showed this enzyme is present in both nucleus and mitochondrion. QPCR and MtOX results reinforce the presence and function of TcMYH in these two organelles. Our data suggest T. cruzi has a functional MYH DNA glycosylase, which participates in nuclear and mitochondrial DNA Base Excision Repair.
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Affiliation(s)
- Marianna Kunrath-Lima
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Caixa Postal 486, Belo Horizonte 30161-970, MG, Brazil
| | - Bruno Marçal Repolês
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Caixa Postal 486, Belo Horizonte 30161-970, MG, Brazil
| | - Ceres Luciana Alves
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Caixa Postal 486, Belo Horizonte 30161-970, MG, Brazil
| | - Carolina Furtado
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Caixa Postal 486, Belo Horizonte 30161-970, MG, Brazil
| | - Matheus Andrade Rajão
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Caixa Postal 486, Belo Horizonte 30161-970, MG, Brazil
| | - Andrea Mara Macedo
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Caixa Postal 486, Belo Horizonte 30161-970, MG, Brazil
| | - Glória Regina Franco
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Caixa Postal 486, Belo Horizonte 30161-970, MG, Brazil.
| | - Sérgio Danilo Junho Pena
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Caixa Postal 486, Belo Horizonte 30161-970, MG, Brazil.
| | - Lucía Valenzuela
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Simon Wisnovsky
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Shana O Kelley
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
| | - Norbel Galanti
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
| | - Gonzalo Cabrera
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
| | - Carlos Renato Machado
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Caixa Postal 486, Belo Horizonte 30161-970, MG, Brazil.
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16
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Genome-wide and protein kinase-focused RNAi screens reveal conserved and novel damage response pathways in Trypanosoma brucei. PLoS Pathog 2017; 13:e1006477. [PMID: 28742144 PMCID: PMC5542689 DOI: 10.1371/journal.ppat.1006477] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 08/03/2017] [Accepted: 06/17/2017] [Indexed: 12/21/2022] Open
Abstract
All cells are subject to structural damage that must be addressed for continued growth. A wide range of damage affects the genome, meaning multiple pathways have evolved to repair or bypass the resulting DNA lesions. Though many repair pathways are conserved, their presence or function can reflect the life style of individual organisms. To identify genome maintenance pathways in a divergent eukaryote and important parasite, Trypanosoma brucei, we performed RNAi screens to identify genes important for survival following exposure to the alkylating agent methyl methanesulphonate. Amongst a cohort of broadly conserved and, therefore, early evolved repair pathways, we reveal multiple activities not so far examined functionally in T. brucei, including DNA polymerases, DNA helicases and chromatin factors. In addition, the screens reveal Trypanosoma- or kinetoplastid-specific repair-associated activities. We also provide focused analyses of repair-associated protein kinases and show that loss of at least nine, and potentially as many as 30 protein kinases, including a nuclear aurora kinase, sensitises T. brucei to alkylation damage. Our results demonstrate the potential for synthetic lethal genome-wide screening of gene function in T. brucei and provide an evolutionary perspective on the repair pathways that underpin effective responses to damage, with particular relevance for related kinetoplastid pathogens. By revealing that a large number of diverse T. brucei protein kinases act in the response to damage, we expand the range of eukaryotic signalling factors implicated in genome maintenance activities. Damage to the genome is a universal threat to life. Though the repair pathways used to tackle damage can be widely conserved, lineage-specific specialisations are found, reflecting the differing life styles of extant organisms. Using RNAi coupled with next generation sequencing we have screened for genes that are important for growth of Trypanosoma brucei, a diverged eukaryotic microbe and important parasite, in the presence of alkylation damage caused by methyl methanesulphonate. We reveal both repair pathway conservation relative to characterised eukaryotes and specialisation, including uncharacterised roles for translesion DNA polymerases, DNA helicases and chromatin factors. Furthermore, we demonstrate that loss of around 15% of T. brucei protein kinases sensitises the parasites to alkylation, indicating phosphorylation signalling plays widespread and under-investigated roles in the damage response pathways of eukaryotes.
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Verissimo-Villela E, Kitahara-Oliveira MY, Reis ABDBD, Albano RM, Da-Cruz AM, Bello AR. Functional complementation of Leishmania (Leishmania) amazonensis AP endonuclease gene (lamap) in Escherichia coli mutant strains challenged with DNA damage agents. Mem Inst Oswaldo Cruz 2017; 111:349-54. [PMID: 27223868 PMCID: PMC4878305 DOI: 10.1590/0074-02760150412] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 04/09/2016] [Indexed: 01/25/2023] Open
Abstract
During its life cycle Leishmania spp. face several stress conditions
that can cause DNA damages. Base Excision Repair plays an important role in DNA
maintenance and it is one of the most conserved mechanisms in all living organisms.
DNA repair in trypanosomatids has been reported only for Old World
Leishmania species. Here the AP endonuclease from
Leishmania (L.) amazonensis was cloned, expressed in
Escherichia coli mutants defective on the DNA repair machinery,
that were submitted to different stress conditions, showing ability to survive in
comparison to the triple null mutant parental strain BW535. Phylogenetic and multiple
sequence analyses also confirmed that LAMAP belongs to the AP endonuclease class of
proteins.
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Affiliation(s)
- Erika Verissimo-Villela
- Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - Milene Yoko Kitahara-Oliveira
- Laboratório Interdisciplinar de Pesquisas Médicas, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
| | - Ana Beatriz de Bragança Dos Reis
- Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - Rodolpho Mattos Albano
- Laboratório de Genoma, Instituto de Biologia Roberto Alcântara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - Alda Maria Da-Cruz
- Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - Alexandre Ribeiro Bello
- Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
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18
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de Faria RC, Vila-Nova LG, Bitar M, Resende BC, Arantes LS, Rebelato AB, Azevedo VAC, Franco GR, Machado CR, Santos LLD, de Oliveira Lopes D. Adenine Glycosylase MutY of Corynebacterium pseudotuberculosis presents the antimutator phenotype and evidences of glycosylase/AP lyase activity in vitro. INFECTION GENETICS AND EVOLUTION 2016; 44:318-329. [PMID: 27456281 DOI: 10.1016/j.meegid.2016.07.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 07/07/2016] [Accepted: 07/21/2016] [Indexed: 01/30/2023]
Abstract
Corynebacterium pseudotuberculosis is the etiological agent of caseous lymphadenitis, a disease that predominantly affects small ruminants, causing significant economic losses worldwide. As a facultative intracellular pathogen, this bacterium is exposed to an environment rich in reactive oxygen species (ROS) within macrophages. To ensure its genetic stability, C. pseudotuberculosis relies on efficient DNA repair pathways for excision of oxidative damage such as 8-oxoguanine, a highly mutagenic lesion. MutY is an adenine glycosylase involved in adenine excision from 8-oxoG:A mismatches avoiding genome mutation incorporation. The purpose of this study was to characterize MutY protein from C. pseudotuberculosis and determine its involvement with DNA repair. In vivo functional complementation assay employing mutY gene deficient Escherichia coli transformed with CpmutY showed a 13.5-fold reduction in the rate of spontaneous mutation, compared to cells transformed with empty vector. Also, under oxidative stress conditions, CpMutY protein favored the growth of mutY deficient E. coli, relative to the same strain in the absence of CpMutY. To demonstrate the involvement of this enzyme in recognition and excision of 8-oxoguanine lesion, an in vitro assay was performed. CpMutY protein was capable of recognizing and excising 8-oxoG:A but not 8-oxoG:C presenting evidences of glycosylase/AP lyase activity in vitro. In silico structural characterization revealed the presence of preserved motifs related to the MutY activity on DNA repair, such as catalytic residues involved in glycosylase/AP lyase activity and structural DNA-binding elements, such as the HhH motif and the [4Fe-4S] cluster. The three-dimensional structure of CpMutY, generated by comparative modeling, exhibits a catalytic domain very similar to that of E. coli MutY. Taken together, these results indicate that the CpmutY encodes a functional protein homologous to MutY from E. coli and is involved in the prevention of mutations and the repair of oxidative DNA lesions.
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Affiliation(s)
- Rafael Cançado de Faria
- Laboratory of Molecular Biology, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
| | - Liliane Gonçalves Vila-Nova
- Laboratory of Molecular Biology, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
| | - Mainá Bitar
- Laboratory of Genetics and Biochemistry, Department of Biochemistry, ICB, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG 31270-901, Brazil.
| | - Bruno Carvalho Resende
- Laboratory of Molecular Biology, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
| | - Larissa Sousa Arantes
- Laboratory of Molecular Biology, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
| | - Arnaldo Basso Rebelato
- Laboratory of Molecular Biology, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
| | - Vasco Ariston Carvalho Azevedo
- Laboratory of Cell and Molecular Genetics, Department of General Biology, ICB, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG 31270-901, Brazil.
| | - Glória Regina Franco
- Laboratory of Genetics and Biochemistry, Department of Biochemistry, ICB, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG 31270-901, Brazil.
| | - Carlos Renato Machado
- Laboratory of Genetics and Biochemistry, Department of Biochemistry, ICB, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG 31270-901, Brazil.
| | - Luciana Lara Dos Santos
- Laboratory of Molecular Biology, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
| | - Débora de Oliveira Lopes
- Laboratory of Molecular Biology, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
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19
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Ormeño F, Barrientos C, Ramirez S, Ponce I, Valenzuela L, Sepúlveda S, Bitar M, Kemmerling U, Machado CR, Cabrera G, Galanti N. Expression and the Peculiar Enzymatic Behavior of the Trypanosoma cruzi NTH1 DNA Glycosylase. PLoS One 2016; 11:e0157270. [PMID: 27284968 PMCID: PMC4902261 DOI: 10.1371/journal.pone.0157270] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 05/26/2016] [Indexed: 02/06/2023] Open
Abstract
Trypanosoma cruzi, the etiological agent of Chagas’ disease, presents three cellular forms (trypomastigotes, epimastigotes and amastigotes), all of which are submitted to oxidative species in its hosts. However, T. cruzi is able to resist oxidative stress suggesting a high efficiency of its DNA repair machinery.The Base Excision Repair (BER) pathway is one of the main DNA repair mechanisms in other eukaryotes and in T. cruzi as well. DNA glycosylases are enzymes involved in the recognition of oxidative DNA damage and in the removal of oxidized bases, constituting the first step of the BER pathway. Here, we describe the presence and activity of TcNTH1, a nuclear T. cruzi DNA glycosylase. Surprisingly, purified recombinant TcNTH1 does not remove the thymine glycol base, but catalyzes the cleavage of a probe showing an AP site. The same activity was found in epimastigote and trypomastigote homogenates suggesting that the BER pathway is not involved in thymine glycol DNA repair. TcNTH1 DNA-binding properties assayed in silico are in agreement with the absence of a thymine glycol removing function of that parasite enzyme. Over expression of TcNTH1 decrease parasite viability when transfected epimastigotes are submitted to a sustained production of H2O2.Therefore, TcNTH1 is the only known NTH1 orthologous unable to eliminate thymine glycol derivatives but that recognizes and cuts an AP site, most probably by a beta-elimination mechanism. We cannot discard that TcNTH1 presents DNA glycosylase activity on other DNA base lesions. Accordingly, a different DNA repair mechanism should be expected leading to eliminate thymine glycol from oxidized parasite DNA. Furthermore, TcNTH1 may play a role in the AP site recognition and processing.
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Affiliation(s)
- Fernando Ormeño
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Camila Barrientos
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Santiago Ramirez
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Iván Ponce
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Lucía Valenzuela
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Sofía Sepúlveda
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Mainá Bitar
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ulrike Kemmerling
- Programa de Anatomía y Biología del Desarrollo, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Carlos Renato Machado
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Gonzalo Cabrera
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- * E-mail: (GC); (NG)
| | - Norbel Galanti
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- * E-mail: (GC); (NG)
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20
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Arantes LS, Nova LGV, Resende BC, Bitar M, Coelho IEV, Miyoshi A, Azevedo VA, Lara dos Santos L, Machado CR, de Oliveira Lopes D. The Corynebacterium pseudotuberculosis genome contains two formamidopyrimidine-DNA glycosylase enzymes, only one of which recognizes and excises 8-oxoguanine lesion. Gene 2016; 575:233-43. [DOI: 10.1016/j.gene.2015.08.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 08/11/2015] [Accepted: 08/30/2015] [Indexed: 10/23/2022]
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21
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Machado-Silva A, Cerqueira PG, Grazielle-Silva V, Gadelha FR, Peloso EDF, Teixeira SMR, Machado CR. How Trypanosoma cruzi deals with oxidative stress: Antioxidant defence and DNA repair pathways. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2016; 767:8-22. [DOI: 10.1016/j.mrrev.2015.12.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/22/2015] [Accepted: 12/23/2015] [Indexed: 02/06/2023]
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22
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Grazielle-Silva V, Zeb TF, Bolderson J, Campos PC, Miranda JB, Alves CL, Machado CR, McCulloch R, Teixeira SMR. Distinct Phenotypes Caused by Mutation of MSH2 in Trypanosome Insect and Mammalian Life Cycle Forms Are Associated with Parasite Adaptation to Oxidative Stress. PLoS Negl Trop Dis 2015; 9:e0003870. [PMID: 26083967 PMCID: PMC4470938 DOI: 10.1371/journal.pntd.0003870] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 06/02/2015] [Indexed: 11/19/2022] Open
Abstract
Background DNA repair mechanisms are crucial for maintenance of the genome in all organisms, including parasites where successful infection is dependent both on genomic stability and sequence variation. MSH2 is an early acting, central component of the Mismatch Repair (MMR) pathway, which is responsible for the recognition and correction of base mismatches that occur during DNA replication and recombination. In addition, recent evidence suggests that MSH2 might also play an important, but poorly understood, role in responding to oxidative damage in both African and American trypanosomes. Methodology/Principal Findings To investigate the involvement of MMR in the oxidative stress response, null mutants of MSH2 were generated in Trypanosoma brucei procyclic forms and in Trypanosoma cruzi epimastigote forms. Unexpectedly, the MSH2 null mutants showed increased resistance to H2O2 exposure when compared with wild type cells, a phenotype distinct from the previously observed increased sensitivity of T. brucei bloodstream forms MSH2 mutants. Complementation studies indicated that the increased oxidative resistance of procyclic T. brucei was due to adaptation to MSH2 loss. In both parasites, loss of MSH2 was shown to result in increased tolerance to alkylation by MNNG and increased accumulation of 8-oxo-guanine in the nuclear and mitochondrial genomes, indicating impaired MMR. In T. cruzi, loss of MSH2 also increases the parasite capacity to survive within host macrophages. Conclusions/Significance Taken together, these results indicate MSH2 displays conserved, dual roles in MMR and in the response to oxidative stress. Loss of the latter function results in life cycle dependent differences in phenotypic outcomes in T. brucei MSH2 mutants, most likely because of the greater burden of oxidative stress in the insect stage of the parasite. Trypanosoma brucei and Trypanosoma cruzi are protozoa parasites that cause sleeping sickness and Chagas disease, respectively, two neglected tropical diseases endemic in sub-Saharan Africa and Latin America. The high genetic diversity found in the T. cruzi population and the highly diverse repertoire of surface glycoprotein genes found in T. brucei are crucial factors that ensure a successful infection in their hosts. Besides responding to host immune responses, these parasites must deal with various sources of oxidative stress that can cause DNA damage. Thus, by determining the right balance between genomic stability and genetic variation, DNA repair pathways have a big impact in the ability of these parasites to maintain infection. This study is focused on the role of a DNA mismatch repair (MMR) protein named MSH2 in protecting these parasites’ DNA against oxidative assault. Using knock-out mutants, we showed that, besides acting in the MMR pathway as a key protein that recognizes and repairs base mismatches, insertions or deletions that can occur after DNA replication, MSH2 has an additional role in the oxidative stress response. Importantly, this extra role of MSH2 seems to be independent of other MMR components and dependent on the parasite developmental stage.
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Affiliation(s)
- Viviane Grazielle-Silva
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- The Wellcome Trust Center for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Tehseen Fatima Zeb
- The Wellcome Trust Center for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Jason Bolderson
- The Wellcome Trust Center for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Priscila C. Campos
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Julia B. Miranda
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Ceres L. Alves
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Carlos R. Machado
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Richard McCulloch
- The Wellcome Trust Center for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, Scotland, United Kingdom
- * E-mail: (RM); (SMRT)
| | - Santuza M. R. Teixeira
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- * E-mail: (RM); (SMRT)
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Heredero-Bermejo I, Criado-Fornelio A, Soliveri J, Díaz-Martín JA, Matilla-Fuentes J, Sánchez-Arias JA, Copa-Patiño JL, Pérez-Serrano J. Development of a new oxygen consumption rate assay in cultures of Acanthamoeba (Protozoa: Lobosea) and its application to evaluate viability and amoebicidal activity in vitro. Exp Parasitol 2015; 155:35-9. [PMID: 25956947 DOI: 10.1016/j.exppara.2015.04.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 03/16/2015] [Accepted: 04/29/2015] [Indexed: 11/29/2022]
Abstract
A new fluorometric method has been developed for measuring the oxygen consumption rate (OCR) of Acanthamoeba cultures in microplates and for screening molecules with amoebicidal activity against this microorganism. The use of a biofunctional matrix (containing an oxygen-sensitive fluorogenic probe) attached to the microplate wells allowed continuous measurement of OCR in the medium, hence assessment of amoebic growth. The new OCR method applied to cell viability yielded a linear relationship and monitoring was much quicker than with indirect viability assays previously used. In addition, two drugs were tested in a cytotoxicity assay monitored by the new OCR viability test. With this procedure, the standard amoebicidal drug chlorhexidine digluconate showed an IC50 of 3.53 + 1.3 mg/l against Acanthamoeba polyphaga and 3.19 + 1.2 mg/l against Acanthamoeba castellanii, whereas a cationic dendrimer [G1Si(NMe3+)4] showed an IC50 of 6.42 + 1.3 mg/l against A. polyphaga. These data agree with previous studies conducted in our laboratory. Therefore, the new OCR method has proven powerful and quick for amoebicidal drug screening and is likely to be applied in biochemical studies concerning protozoa respiration and metabolism.
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Affiliation(s)
- I Heredero-Bermejo
- Departamento de Biomedicina y Biotecnología, Facultad de Farmacia, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.
| | - A Criado-Fornelio
- Departamento de Biomedicina y Biotecnología, Facultad de Farmacia, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain
| | - J Soliveri
- Departamento de Biomedicina y Biotecnología, Facultad de Farmacia, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain
| | - J A Díaz-Martín
- Oxoprobics Biosciences S.L., Francisco Giralte 2, Desp.12, 28002 Madrid, Spain
| | - J Matilla-Fuentes
- Oxoprobics Biosciences S.L., Francisco Giralte 2, Desp.12, 28002 Madrid, Spain
| | - J A Sánchez-Arias
- Oxoprobics Biosciences S.L., Francisco Giralte 2, Desp.12, 28002 Madrid, Spain
| | - J L Copa-Patiño
- Departamento de Biomedicina y Biotecnología, Facultad de Farmacia, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain
| | - J Pérez-Serrano
- Departamento de Biomedicina y Biotecnología, Facultad de Farmacia, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain
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24
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DNA repair pathways in trypanosomatids: from DNA repair to drug resistance. Microbiol Mol Biol Rev 2014; 78:40-73. [PMID: 24600040 DOI: 10.1128/mmbr.00045-13] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
All living organisms are continuously faced with endogenous or exogenous stress conditions affecting genome stability. DNA repair pathways act as a defense mechanism, which is essential to maintain DNA integrity. There is much to learn about the regulation and functions of these mechanisms, not only in human cells but also equally in divergent organisms. In trypanosomatids, DNA repair pathways protect the genome against mutations but also act as an adaptive mechanism to promote drug resistance. In this review, we scrutinize the molecular mechanisms and DNA repair pathways which are conserved in trypanosomatids. The recent advances made by the genome consortiums reveal the complete genomic sequences of several pathogens. Therefore, using bioinformatics and genomic sequences, we analyze the conservation of DNA repair proteins and their key protein motifs in trypanosomatids. We thus present a comprehensive view of DNA repair processes in trypanosomatids at the crossroads of DNA repair and drug resistance.
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25
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Rajão MA, Furtado C, Alves CL, Passos-Silva DG, de Moura MB, Schamber-Reis BL, Kunrath-Lima M, Zuma AA, Vieira-da-Rocha JP, Garcia JBF, Mendes IC, Pena SDJ, Macedo AM, Franco GR, de Souza-Pinto NC, de Medeiros MHG, Cruz AK, Motta MCM, Teixeira SMR, Machado CR. Unveiling benznidazole's mechanism of action through overexpression of DNA repair proteins in Trypanosoma cruzi. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2014; 55:309-21. [PMID: 24347026 DOI: 10.1002/em.21839] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 11/22/2013] [Accepted: 11/24/2013] [Indexed: 05/14/2023]
Abstract
Benznidazole (BZ) is the most commonly used drug for the treatment of Chagas disease. Although BZ is known to induce the formation of free radicals and electrophilic metabolites within the parasite Trypanosoma cruzi, its precise mechanisms of action are still elusive. Here, we analyzed the survival of T. cruzi exposed to BZ using genetically modified parasites overexpressing different DNA repair proteins. Our results indicate that BZ induces oxidation mainly in the nucleotide pool, as heterologous expression of the nucleotide pyrophosphohydrolase MutT (but not overexpression of the glycosylase TcOgg1) increased drug resistance in the parasite. In addition, electron microscopy indicated that BZ catalyzes the formation of double-stranded breaks in the parasite, as its genomic DNA undergoes extensive heterochromatin unpacking following exposure to the drug. Furthermore, the overexpression of proteins involved in the recombination-mediated DNA repair increased resistance to BZ, reinforcing the idea that the drug causes double-stranded breaks. Our results also show that the overexpression of mitochondrial DNA repair proteins increase parasite survival upon BZ exposure, indicating that the drug induces lesions in the mitochondrial DNA as well. These findings suggest that BZ preferentially oxidizes the nucleotide pool, and the extensive incorporation of oxidized nucleotides during DNA replication leads to potentially lethal double-stranded DNA breaks in T. cruzi DNA.
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Affiliation(s)
- Matheus Andrade Rajão
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, UFMG, Belo Horizonte, Minas Gerais
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26
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Sepúlveda S, Valenzuela L, Ponce I, Sierra S, Bahamondes P, Ramirez S, Rojas V, Kemmerling U, Galanti N, Cabrera G. Expression, Functionality, and Localization of Apurinic/Apyrimidinic Endonucleases in Replicative and Non-Replicative Forms ofTrypanosoma cruzi. J Cell Biochem 2013; 115:397-409. [DOI: 10.1002/jcb.24675] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/10/2013] [Indexed: 12/11/2022]
Affiliation(s)
- S. Sepúlveda
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - L. Valenzuela
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - I. Ponce
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - S. Sierra
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - P. Bahamondes
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - S. Ramirez
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - V. Rojas
- Laboratorio de Genética e Inmunología Molecular; Instituto de Biología, Pontificia Universidad Católica de Valparaíso; Chile
| | - U. Kemmerling
- Programa de Anatomía y Biología del Desarrollo; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - N. Galanti
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - G. Cabrera
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
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