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Tamim El Jarkass H, Mok C, Schertzberg MR, Fraser AG, Troemel ER, Reinke AW. An intestinally secreted host factor promotes microsporidia invasion of C. elegans. eLife 2022; 11:72458. [PMID: 34994689 PMCID: PMC8806185 DOI: 10.7554/elife.72458] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 01/06/2022] [Indexed: 12/11/2022] Open
Abstract
Microsporidia are ubiquitous obligate intracellular pathogens of animals. These parasites often infect hosts through an oral route, but little is known about the function of host intestinal proteins that facilitate microsporidia invasion. To identify such factors necessary for infection by Nematocida parisii, a natural microsporidian pathogen of Caenorhabditis elegans, we performed a forward genetic screen to identify mutant animals that have a Fitness Advantage with Nematocida (Fawn). We isolated four fawn mutants that are resistant to Nematocida infection and contain mutations in T14E8.4, which we renamed aaim-1 (Antibacterial and Aids invasion by Microsporidia). Expression of AAIM-1 in the intestine of aaim-1 animals restores N. parisii infectivity and this rescue of infectivity is dependent upon AAIM-1 secretion. N. parisii spores in aaim-1 animals are improperly oriented in the intestinal lumen, leading to reduced levels of parasite invasion. Conversely, aaim-1 mutants display both increased colonization and susceptibility to the bacterial pathogen Pseudomonas aeruginosa and overexpression ofaaim-1 reduces P. aeruginosa colonization. Competitive fitness assays show that aaim-1 mutants are favored in the presence of N. parisii but disadvantaged on P. aeruginosa compared to wild-type animals. Together, this work demonstrates how microsporidia exploits a secreted protein to promote host invasion. Our results also suggest evolutionary trade-offs may exist to optimizing host defense against multiple classes of pathogens.
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Affiliation(s)
| | - Calvin Mok
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | | | - Andrew G Fraser
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Emily R Troemel
- Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Aaron W Reinke
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
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Lautens MJ, Tan JH, Serrat X, Del Borrello S, Schertzberg MR, Fraser AG. Identification of enzymes that have helminth-specific active sites and are required for Rhodoquinone-dependent metabolism as targets for new anthelmintics. PLoS Negl Trop Dis 2021; 15:e0009991. [PMID: 34843467 PMCID: PMC8659336 DOI: 10.1371/journal.pntd.0009991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 12/09/2021] [Accepted: 11/11/2021] [Indexed: 11/18/2022] Open
Abstract
Soil transmitted helminths (STHs) are major human pathogens that infect over a billion people. Resistance to current anthelmintics is rising and new drugs are needed. Here we combine multiple approaches to find druggable targets in the anaerobic metabolic pathways STHs need to survive in their mammalian host. These require rhodoquinone (RQ), an electron carrier used by STHs and not their hosts. We identified 25 genes predicted to act in RQ-dependent metabolism including sensing hypoxia and RQ synthesis and found 9 are required. Since all 9 have mammalian orthologues, we used comparative genomics and structural modeling to identify those with active sites that differ between host and parasite. Together, we found 4 genes that are required for RQ-dependent metabolism and have different active sites. Finding these high confidence targets can open up in silico screens to identify species selective inhibitors of these enzymes as new anthelmintics.
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Affiliation(s)
- Margot J. Lautens
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - June H. Tan
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Xènia Serrat
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | | | | | - Andrew G. Fraser
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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Tan JH, Lautens M, Romanelli-Cedrez L, Wang J, Schertzberg MR, Reinl SR, Davis RE, Shepherd JN, Fraser AG, Salinas G. Alternative splicing of coq-2 controls the levels of rhodoquinone in animals. eLife 2020; 9:e56376. [PMID: 32744503 PMCID: PMC7434440 DOI: 10.7554/elife.56376] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 08/02/2020] [Indexed: 11/17/2022] Open
Abstract
Parasitic helminths use two benzoquinones as electron carriers in the electron transport chain. In normoxia, they use ubiquinone (UQ), but in anaerobic conditions inside the host, they require rhodoquinone (RQ) and greatly increase RQ levels. We previously showed the switch from UQ to RQ synthesis is driven by a change of substrates by the polyprenyltransferase COQ-2 (Del Borrello et al., 2019; Roberts Buceta et al., 2019); however, the mechanism of substrate selection is not known. Here, we show helminths synthesize two coq-2 splice forms, coq-2a and coq-2e, and the coq-2e-specific exon is only found in species that synthesize RQ. We show that in Caenorhabditis elegans COQ-2e is required for efficient RQ synthesis and survival in cyanide. Importantly, parasites switch from COQ-2a to COQ-2e as they transit into anaerobic environments. We conclude helminths switch from UQ to RQ synthesis principally via changes in the alternative splicing of coq-2.
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Affiliation(s)
- June H Tan
- The Donnelly Centre, University of TorontoTorontoCanada
| | | | - Laura Romanelli-Cedrez
- Laboratorio de Biología de Gusanos. Unidad Mixta, Departamento de Biociencias, Facultad de Química, Universidad de la República - Institut Pasteur de MontevideoMontevideoUruguay
| | - Jianbin Wang
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of MedicineAuroraUnited States
- Department of Biochemistry and Cellular and Molecular Biology, University of TennesseeKnoxvilleUnited States
| | | | - Samantha R Reinl
- Department of Chemistry and Biochemistry, Gonzaga UniversitySpokaneUnited States
| | - Richard E Davis
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of MedicineAuroraUnited States
| | - Jennifer N Shepherd
- Department of Chemistry and Biochemistry, Gonzaga UniversitySpokaneUnited States
| | | | - Gustavo Salinas
- Laboratorio de Biología de Gusanos. Unidad Mixta, Departamento de Biociencias, Facultad de Química, Universidad de la República - Institut Pasteur de MontevideoMontevideoUruguay
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Del Borrello S, Lautens M, Dolan K, Tan JH, Davie T, Schertzberg MR, Spensley MA, Caudy AA, Fraser AG. Rhodoquinone biosynthesis in C. elegans requires precursors generated by the kynurenine pathway. eLife 2019; 8:e48165. [PMID: 31232688 PMCID: PMC6656428 DOI: 10.7554/elife.48165] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 06/22/2019] [Indexed: 02/05/2023] Open
Abstract
Parasitic helminths infect over a billion humans. To survive in the low oxygen environment of their hosts, these parasites use unusual anaerobic metabolism - this requires rhodoquinone (RQ), an electron carrier that is made by very few animal species. Crucially RQ is not made or used by any parasitic hosts and RQ synthesis is thus an ideal target for anthelmintics. However, little is known about how RQ is made and no drugs are known to block RQ synthesis. C. elegans makes RQ and can use RQ-dependent metabolic pathways - here, we use C. elegans genetics to show that tryptophan degradation via the kynurenine pathway is required to generate the key amine-containing precursors for RQ synthesis. We show that C. elegans requires RQ for survival in hypoxic conditions and, finally, we establish a high throughput assay for drugs that block RQ-dependent metabolism. This may drive the development of a new class of anthelmintic drugs. This study is a key first step in understanding how RQ is made in parasitic helminths.
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Affiliation(s)
| | | | | | - June H Tan
- The Donnelly CentreUniversity of TorontoTorontoCanada
| | - Taylor Davie
- The Donnelly CentreUniversity of TorontoTorontoCanada
| | | | - Mark A Spensley
- The Donnelly CentreUniversity of TorontoTorontoCanada
- Whole Animal PhenotypingPhenalysys IncTorontoCanada
| | - Amy A Caudy
- The Donnelly CentreUniversity of TorontoTorontoCanada
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Weerasinghe JP, Dong T, Schertzberg MR, Kirchhof MG, Sun Y, Schellhorn HE. Stationary phase expression of the arginine biosynthetic operon argCBH in Escherichia coli. BMC Microbiol 2006; 6:14. [PMID: 16504055 PMCID: PMC1413537 DOI: 10.1186/1471-2180-6-14] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Accepted: 02/22/2006] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Arginine biosynthesis in Escherichia coli is elevated in response to nutrient limitation, stress or arginine restriction. Though control of the pathway in response to arginine limitation is largely modulated by the ArgR repressor, other factors may be involved in increased stationary phase and stress expression. RESULTS In this study, we report that expression of the argCBH operon is induced in stationary phase cultures and is reduced in strains possessing a mutation in rpoS, which encodes an alternative sigma factor. Using strains carrying defined argR, and rpoS mutations, we evaluated the relative contributions of these two regulators to the expression of argH using operon-lacZ fusions. While ArgR was the main factor responsible for modulating expression of argCBH, RpoS was also required for full expression of this biosynthetic operon at low arginine concentrations (below 60 microM L-arginine), a level at which growth of an arginine auxotroph was limited by arginine. When the argCBH operon was fully de-repressed (arginine limited), levels of expression were only one third of those observed in deltaargR mutants, indicating that the argCBH operon is partially repressed by ArgR even in the absence of arginine. In addition, argCBH expression was 30-fold higher in deltaargR mutants relative to levels found in wild type, fully-repressed strains, and this expression was independent of RpoS. CONCLUSION The results of this study indicate that both derepression and positive control by RpoS are required for full control of arginine biosynthesis in stationary phase cultures of E. coli.
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Affiliation(s)
- Jeevaka P Weerasinghe
- McMaster University, Department of Biology, Life Sciences Building, Rm. 218, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1
| | - Tao Dong
- McMaster University, Department of Biology, Life Sciences Building, Rm. 218, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1
| | - Michael R Schertzberg
- McMaster University, Department of Biology, Life Sciences Building, Rm. 218, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1
| | - Mark G Kirchhof
- McMaster University, Department of Biology, Life Sciences Building, Rm. 218, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1
| | - Yuan Sun
- McMaster University, Department of Biology, Life Sciences Building, Rm. 218, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1
| | - Herb E Schellhorn
- McMaster University, Department of Biology, Life Sciences Building, Rm. 218, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1
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Patten CL, Kirchhof MG, Schertzberg MR, Morton RA, Schellhorn HE. Microarray analysis of RpoS-mediated gene expression in Escherichia coli K-12. Mol Genet Genomics 2004; 272:580-91. [PMID: 15558318 DOI: 10.1007/s00438-004-1089-2] [Citation(s) in RCA: 190] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Accepted: 10/28/2004] [Indexed: 12/01/2022]
Abstract
The alternative sigma factor RpoS controls the expression of many stationary-phase genes in Escherichia coli and other bacteria. Though the RpoS regulon is a large, conserved system that is critical for adaptation to nutrient deprivation and other stresses, it remains incompletely characterized. In this study, we have used oligonucleotide arrays to delineate the transcriptome that is controlled by RpoS during entry into stationary phase of cultures growing in rich medium. The expression of known RpoS-dependent genes was confirmed to be regulated by RpoS, thus validating the use of microarrays for expression analysis. The total number of positively regulated stationary-phase genes was found to be greater than 100. More than 45 new genes were identified as positively controlled by RpoS. Surprisingly, a similar number of genes were found to be negatively regulated by RpoS, and these included almost all genes required for flagellum biosynthesis, genes encoding enzymes of the TCA cycle, and a physically contiguous group of genes located in the Rac prophage region. Negative regulation by RpoS is thus much more extensive than has previously been recognized, and is likely to be an important contributing factor to the competitive growth advantage of rpoS mutants reported in previous studies.
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Affiliation(s)
- C L Patten
- Department of Biology, McMaster University, Hamilton, Ontario, L8S 4K1, Canada
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