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Li SJ, Zhang X, Lukeš J, Li BQ, Wang JF, Qu LH, Hide G, Lai DH, Lun ZR. Novel organization of mitochondrial minicircles and guide RNAs in the zoonotic pathogen Trypanosoma lewisi. Nucleic Acids Res 2020; 48:9747-9761. [PMID: 32853372 PMCID: PMC7515712 DOI: 10.1093/nar/gkaa700] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 08/06/2020] [Accepted: 08/11/2020] [Indexed: 01/01/2023] Open
Abstract
Kinetoplastid flagellates are known for several unusual features, one of which is their complex mitochondrial genome, known as kinetoplast (k) DNA, composed of mutually catenated maxi- and minicircles. Trypanosoma lewisi is a member of the Stercorarian group of trypanosomes which is, based on human infections and experimental data, now considered a zoonotic pathogen. By assembling a total of 58 minicircle classes, which fall into two distinct categories, we describe a novel type of kDNA organization in T. lewisi. RNA-seq approaches allowed us to map the details of uridine insertion and deletion editing events upon the kDNA transcriptome. Moreover, sequencing of small RNA molecules enabled the identification of 169 unique guide (g) RNA genes, with two differently organized minicircle categories both encoding essential gRNAs. The unprecedented organization of minicircles and gRNAs in T. lewisi broadens our knowledge of the structure and expression of the mitochondrial genomes of these human and animal pathogens. Finally, a scenario describing the evolution of minicircles is presented.
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Affiliation(s)
- Su-Jin Li
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, and Key Laboratory of Tropical Diseases Control of the Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China
| | - Xuan Zhang
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, and Key Laboratory of Tropical Diseases Control of the Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences and Faculty of Science, University of South Bohemia, České Budějovice (Budweis) 37005, Czech Republic
| | - Bi-Qi Li
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, and Key Laboratory of Tropical Diseases Control of the Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China
| | - Ju-Feng Wang
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, and Key Laboratory of Tropical Diseases Control of the Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China
| | - Liang-Hu Qu
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China
| | - Geoff Hide
- Ecosystems and Environment Research Centre and Biomedical Research Centre, School of Science, Engineering and Environment, University of Salford, Salford, UK
| | - De-Hua Lai
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, and Key Laboratory of Tropical Diseases Control of the Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China
| | - Zhao-Rong Lun
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, and Key Laboratory of Tropical Diseases Control of the Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China
- Ecosystems and Environment Research Centre and Biomedical Research Centre, School of Science, Engineering and Environment, University of Salford, Salford, UK
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The double-edged sword in pathogenic trypanosomatids: the pivotal role of mitochondria in oxidative stress and bioenergetics. BIOMED RESEARCH INTERNATIONAL 2014; 2014:614014. [PMID: 24800243 PMCID: PMC3988864 DOI: 10.1155/2014/614014] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 02/17/2014] [Indexed: 11/17/2022]
Abstract
The pathogenic trypanosomatids Trypanosoma brucei, Trypanosoma cruzi, and Leishmania spp. are the causative agents of African trypanosomiasis, Chagas disease, and leishmaniasis, respectively. These diseases are considered to be neglected tropical illnesses that persist under conditions of poverty and are concentrated in impoverished populations in the developing world. Novel efficient and nontoxic drugs are urgently needed as substitutes for the currently limited chemotherapy. Trypanosomatids display a single mitochondrion with several peculiar features, such as the presence of different energetic and antioxidant enzymes and a specific arrangement of mitochondrial DNA (kinetoplast DNA). Due to mitochondrial differences between mammals and trypanosomatids, this organelle is an excellent candidate for drug intervention. Additionally, during trypanosomatids' life cycle, the shape and functional plasticity of their single mitochondrion undergo profound alterations, reflecting adaptation to different environments. In an uncoupling situation, the organelle produces high amounts of reactive oxygen species. However, these species role in parasite biology is still controversial, involving parasite death, cell signalling, or even proliferation. Novel perspectives on trypanosomatid-targeting chemotherapy could be developed based on better comprehension of mitochondrial oxidative regulation processes.
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Abstract
One of the most fascinating and unusual features of trypanosomatids, parasites that cause disease in many tropical countries, is their mitochondrial DNA. This genome, known as kinetoplast DNA (kDNA), is organized as a single, massive DNA network formed of interlocked DNA rings. In this review, we discuss recent studies on kDNA structure and replication, emphasizing recent developments on replication enzymes, how the timing of kDNA synthesis is controlled during the cell cycle, and the machinery for segregating daughter networks after replication.
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Affiliation(s)
- Robert E Jensen
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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Teixeira ARL, Hecht MM, Guimaro MC, Sousa AO, Nitz N. Pathogenesis of chagas' disease: parasite persistence and autoimmunity. Clin Microbiol Rev 2011; 24:592-630. [PMID: 21734249 PMCID: PMC3131057 DOI: 10.1128/cmr.00063-10] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Acute Trypanosoma cruzi infections can be asymptomatic, but chronically infected individuals can die of Chagas' disease. The transfer of the parasite mitochondrial kinetoplast DNA (kDNA) minicircle to the genome of chagasic patients can explain the pathogenesis of the disease; in cases of Chagas' disease with evident cardiomyopathy, the kDNA minicircles integrate mainly into retrotransposons at several chromosomes, but the minicircles are also detected in coding regions of genes that regulate cell growth, differentiation, and immune responses. An accurate evaluation of the role played by the genotype alterations in the autoimmune rejection of self-tissues in Chagas' disease is achieved with the cross-kingdom chicken model system, which is refractory to T. cruzi infections. The inoculation of T. cruzi into embryonated eggs prior to incubation generates parasite-free chicks, which retain the kDNA minicircle sequence mainly in the macrochromosome coding genes. Crossbreeding transfers the kDNA mutations to the chicken progeny. The kDNA-mutated chickens develop severe cardiomyopathy in adult life and die of heart failure. The phenotyping of the lesions revealed that cytotoxic CD45, CD8(+) γδ, and CD8α(+) T lymphocytes carry out the rejection of the chicken heart. These results suggest that the inflammatory cardiomyopathy of Chagas' disease is a genetically driven autoimmune disease.
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Affiliation(s)
- Antonio R L Teixeira
- Chagas Disease Multidisciplinary Research Laboratory, University of Brasilia, Federal District, Brazil.
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Teixeira ARL, Gomes C, Nitz N, Sousa AO, Alves RM, Guimaro MC, Cordeiro C, Bernal FM, Rosa AC, Hejnar J, Leonardecz E, Hecht MM. Trypanosoma cruzi in the chicken model: Chagas-like heart disease in the absence of parasitism. PLoS Negl Trop Dis 2011; 5:e1000. [PMID: 21468314 PMCID: PMC3066158 DOI: 10.1371/journal.pntd.0001000] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 03/07/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The administration of anti-trypanosome nitroderivatives curtails Trypanosoma cruzi infection in Chagas disease patients, but does not prevent destructive lesions in the heart. This observation suggests that an effective treatment for the disease requires understanding its pathogenesis. METHODOLOGY/PRINCIPAL FINDINGS To understand the origin of clinical manifestations of the heart disease we used a chicken model system in which infection can be initiated in the egg, but parasite persistence is precluded. T. cruzi inoculation into the air chamber of embryonated chicken eggs generated chicks that retained only the parasite mitochondrial kinetoplast DNA minicircle in their genome after eight days of gestation. Crossbreeding showed that minicircles were transferred vertically via the germ line to chicken progeny. Minicircle integration in coding regions was shown by targeted-primer thermal asymmetric interlaced PCR, and detected by direct genomic analysis. The kDNA-mutated chickens died with arrhythmias, shortness of breath, cyanosis and heart failure. These chickens with cardiomyopathy had rupture of the dystrophin and other genes that regulate cell growth and differentiation. Tissue pathology revealed inflammatory dilated cardiomegaly whereby immune system mononuclear cells lyse parasite-free target heart fibers. The heart cell destruction implicated a thymus-dependent, autoimmune; self-tissue rejection carried out by CD45(+), CD8γδ(+), and CD8α lymphocytes. CONCLUSIONS/SIGNIFICANCE These results suggest that genetic alterations resulting from kDNA integration in the host genome lead to autoimmune-mediated destruction of heart tissue in the absence of T. cruzi parasites.
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Affiliation(s)
- Antonio R L Teixeira
- Chagas Disease Multidisciplinary Research Laboratory, Faculty of Medicine, University of Brasilia, Brasilia, Federal District, Brazil.
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Inheritance of DNA transferred from American trypanosomes to human hosts. PLoS One 2010; 5:e9181. [PMID: 20169193 PMCID: PMC2820539 DOI: 10.1371/journal.pone.0009181] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Accepted: 01/04/2010] [Indexed: 01/09/2023] Open
Abstract
Interspecies DNA transfer is a major biological process leading to the accumulation of mutations inherited by sexual reproduction among eukaryotes. Lateral DNA transfer events and their inheritance has been challenging to document. In this study we modified a thermal asymmetric interlaced PCR by using additional targeted primers, along with Southern blots, fluorescence techniques, and bioinformatics, to identify lateral DNA transfer events from parasite to host. Instances of naturally occurring human infections by Trypanosoma cruzi are documented, where mitochondrial minicircles integrated mainly into retrotransposable LINE-1 of various chromosomes. The founders of five families show minicircle integrations that were transferred vertically to their progeny. Microhomology end-joining of 6 to 22 AC-rich nucleotide repeats in the minicircles and host DNA mediates foreign DNA integration. Heterogeneous minicircle sequences were distributed randomly among families, with diversity increasing due to subsequent rearrangement of inserted fragments. Mosaic recombination and hitchhiking on retrotransposition events to different loci were more prevalent in germ line as compared to somatic cells. Potential new genes, pseudogenes, and knockouts were identified. A pathway of minicircle integration and maintenance in the host genome is suggested. Thus, infection by T. cruzi has the unexpected consequence of increasing human genetic diversity, and Chagas disease may be a fortuitous share of negative selection. This demonstration of contemporary transfer of eukaryotic DNA to the human genome and its subsequent inheritance by descendants introduces a significant change in the scientific concept of evolutionary biology and medicine.
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