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Renaud EA, Maupin AJM, Bordat Y, Graindorge A, Berry L, Besteiro S. Iron depletion has different consequences on the growth and survival of Toxoplasma gondii strains. Virulence 2024; 15:2329566. [PMID: 38509723 PMCID: PMC10962585 DOI: 10.1080/21505594.2024.2329566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 03/07/2024] [Indexed: 03/22/2024] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite responsible for a pathology called toxoplasmosis, which primarily affects immunocompromised individuals and developing foetuses. The parasite can scavenge essential nutrients from its host to support its growth and survival. Among them, iron is one of the most important elements needed to sustain basic cellular functions as it is involved in a number of key metabolic processes, including oxygen transport, redox balance, and electron transport. We evaluated the effects of an iron chelator on the development of several parasite strains and found that they differed in their ability to tolerate iron depletion. The growth of parasites usually associated with a model of acute toxoplasmosis was strongly affected by iron depletion, whereas cystogenic strains were less sensitive as they were able to convert into persisting developmental forms that are associated with the chronic form of the disease. Ultrastructural and biochemical characterization of the impact of iron depletion on parasites also highlighted striking changes in both their metabolism and that of the host, with a marked accumulation of lipid droplets and perturbation of lipid homoeostasis. Overall, our study demonstrates that although acute iron depletion has an important effect on the growth of T. gondii, it has a more profound impact on actively dividing parasites, whereas less metabolically active parasite forms may be able to avoid some of the most detrimental consequences.
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Affiliation(s)
- Eléa A. Renaud
- LPHI, University Montpellier, Inserm, CNRS, Montpellier, France
| | | | - Yann Bordat
- LPHI, University Montpellier, Inserm, CNRS, Montpellier, France
| | | | - Laurence Berry
- LPHI, University Montpellier, Inserm, CNRS, Montpellier, France
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2
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Wang F, Holmes MJ, Hong HJ, Thaprawat P, Kannan G, Huynh MH, Schultz TL, Licon MH, Lourido S, Dong W, Brito Querido J, Sullivan WJ, O'Leary SE, Carruthers VB. Translation initiation factor eIF1.2 promotes Toxoplasma stage conversion by regulating levels of key differentiation factors. Nat Commun 2024; 15:4385. [PMID: 38782906 PMCID: PMC11116398 DOI: 10.1038/s41467-024-48685-4] [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: 11/16/2023] [Accepted: 05/07/2024] [Indexed: 05/25/2024] Open
Abstract
The parasite Toxoplasma gondii persists in its hosts by converting from replicating tachyzoites to latent bradyzoites housed in tissue cysts. The molecular mechanisms that mediate T. gondii differentiation remain poorly understood. Through a mutagenesis screen, we identified translation initiation factor eIF1.2 as a critical factor for T. gondii differentiation. A F97L mutation in eIF1.2 or the genetic ablation of eIF1.2 (∆eif1.2) markedly impeded bradyzoite cyst formation in vitro and in vivo. We demonstrated, at single-molecule level, that the eIF1.2 F97L mutation impacts the scanning process of the ribosome preinitiation complex on a model mRNA. RNA sequencing and ribosome profiling experiments unveiled that ∆eif1.2 parasites are defective in upregulating bradyzoite induction factors BFD1 and BFD2 during stress-induced differentiation. Forced expression of BFD1 or BFD2 significantly restored differentiation in ∆eif1.2 parasites. Together, our findings suggest that eIF1.2 functions by regulating the translation of key differentiation factors necessary to establish chronic toxoplasmosis.
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Affiliation(s)
- Fengrong Wang
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Michael J Holmes
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Hea Jin Hong
- Department of Biochemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Pariyamon Thaprawat
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
- Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Geetha Kannan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - My-Hang Huynh
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Tracey L Schultz
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | | | - Sebastian Lourido
- Whitehead Institute, Cambridge, MA, 02142, USA
- Biology Department, Massachusetts Institute of Technology, Cambridge, MA, 02142, USA
| | - Wenzhao Dong
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
- Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jailson Brito Querido
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
- Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - William J Sullivan
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Microbiology & Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Seán E O'Leary
- Department of Biochemistry, University of California Riverside, Riverside, CA, 92521, USA
- Center for RNA Biology and Medicine, University of California Riverside, Riverside, CA, 92521, USA
| | - Vern B Carruthers
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
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Yang X, Yang J, Lyu M, Li Y, Liu A, Shen B. The α subunit of AMP-activated protein kinase is critical for the metabolic success and tachyzoite proliferation of Toxoplasma gondii. Microb Biotechnol 2024; 17:e14455. [PMID: 38635138 PMCID: PMC11025617 DOI: 10.1111/1751-7915.14455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/06/2024] [Accepted: 03/09/2024] [Indexed: 04/19/2024] Open
Abstract
Toxoplasma gondii is a zoonotic parasite infecting humans and nearly all warm-blooded animals. Successful parasitism in diverse hosts at various developmental stages requires the parasites to fine tune their metabolism according to environmental cues and the parasite's needs. By manipulating the β and γ subunits, we have previously shown that AMP-activated protein kinase (AMPK) has critical roles in regulating the metabolic and developmental programmes. However, the biological functions of the α catalytic subunit have not been established. T. gondii encodes a canonical AMPKα, as well as a KIN kinase whose kinase domain has high sequence similarities to those of classic AMPKα proteins. Here, we found that TgKIN is dispensable for tachyzoite growth, whereas TgAMPKα is essential. Depletion of TgAMPKα expression resulted in decreased ATP levels and reduced metabolic flux in glycolysis and the tricarboxylic acid cycle, confirming that TgAMPK is involved in metabolic regulation and energy homeostasis in the parasite. Sequential truncations at the C-terminus found an α-helix that is key for the function of TgAMPKα. The amino acid sequences of this α-helix are not conserved among various AMPKα proteins, likely because it is involved in interactions with TgAMPKβ, which only have limited sequence similarities to AMPKβ in other eukaryotes. The essential role of the less conserved C-terminus of TgAMPKα provides opportunities for parasite specific drug designs targeting TgAMPKα.
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Affiliation(s)
- Xuke Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary MedicineHuazhong Agricultural UniversityWuhanHubei ProvinceChina
- Research Center for Infectious Diseases, Department of Pathogen Biology, School of Basic Medical SciencesAnhui Medical UniversityHefeiChina
| | - Jichao Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary MedicineHuazhong Agricultural UniversityWuhanHubei ProvinceChina
| | - Mengyu Lyu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary MedicineHuazhong Agricultural UniversityWuhanHubei ProvinceChina
| | - Yaqiong Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary MedicineHuazhong Agricultural UniversityWuhanHubei ProvinceChina
| | - Anqi Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary MedicineHuazhong Agricultural UniversityWuhanHubei ProvinceChina
| | - Bang Shen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary MedicineHuazhong Agricultural UniversityWuhanHubei ProvinceChina
- Hubei Hongshan LaboratoryWuhanHubei ProvinceChina
- Key Laboratory of Preventive Medicine in Hubei ProvinceHuazhong Agricultural UniversityWuhanHubei ProvinceChina
- Shenzhen Institute of Nutrition and HealthHuazhong Agricultural UniversityShenzhenGuangdong ProvinceChina
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Xu R, Beatty WL, Greigert V, Witola WH, Sibley LD. Multiple pathways for glucose phosphate transport and utilization support growth of Cryptosporidium parvum. Nat Commun 2024; 15:380. [PMID: 38191884 PMCID: PMC10774378 DOI: 10.1038/s41467-024-44696-3] [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: 07/25/2023] [Accepted: 12/21/2023] [Indexed: 01/10/2024] Open
Abstract
Cryptosporidium parvum is an obligate intracellular parasite with a highly reduced mitochondrion that lacks the tricarboxylic acid cycle and the ability to generate ATP, making the parasite reliant on glycolysis. Genetic ablation experiments demonstrated that neither of the two putative glucose transporters CpGT1 and CpGT2 were essential for growth. Surprisingly, hexokinase was also dispensable for parasite growth while the downstream enzyme aldolase was required, suggesting the parasite has an alternative way of obtaining phosphorylated hexose. Complementation studies in E. coli support a role for direct transport of glucose-6-phosphate from the host cell by the parasite transporters CpGT1 and CpGT2, thus bypassing a requirement for hexokinase. Additionally, the parasite obtains phosphorylated glucose from amylopectin stores that are released by the action of the essential enzyme glycogen phosphorylase. Collectively, these findings reveal that C. parvum relies on multiple pathways to obtain phosphorylated glucose both for glycolysis and to restore carbohydrate reserves.
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Affiliation(s)
- Rui Xu
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63130, USA
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Wandy L Beatty
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63130, USA
| | - Valentin Greigert
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63130, USA
| | - William H Witola
- Department of Pathobiology, University of Illinois Urbana-Champaign, Urbana, IL, 61802, USA
| | - L David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63130, USA.
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5
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Murphy RD, Troublefield CA, Miracle JS, Young LEA, Brizzee CO, Dhara A, Sun RC, Vander Kooi CW, Gentry MS, Sinai AP. TgLaforin, a glucan phosphatase, reveals the dynamic role of storage polysaccharides in Toxoplasma gondii tachyzoites and bradyzoites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.29.560185. [PMID: 37808860 PMCID: PMC10557770 DOI: 10.1101/2023.09.29.560185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
The asexual stages of Toxoplasma gondii are defined by the rapidly growing tachyzoite during the acute infection and by the slow growing bradyzoite housed within tissue cysts during the chronic infection. These stages represent unique physiological states, each with distinct glucans reflecting differing metabolic needs. A defining feature of T. gondii bradyzoites is the presence of insoluble storage glucans known as amylopectin granules (AGs) that are believed to play a role in reactivation, but their functions during the chronic infection remain largely unexplored. More recently, the presence of storage glucans has been recognized in tachyzoites where their precise function and architecture have yet to be fully defined. Importantly, the T. gondii genome encodes activities needed for glucan turnover: a glucan phosphatase (TgLaforin; TGME49_205290) and a glucan kinase (TgGWD; TGME49_214260) that catalyze a cycle of reversible glucan phosphorylation required for glucan degradation by amylases. The expression of these enzymes in tachyzoites supports the existence of a storage glucan, evidence that is corroborated by specific labeling with the anti-glycogen antibody IV58B6. Disruption of reversible glucan phosphorylation via a CRISPR/Cas9 knockout (KO) of TgLaforin revealed no growth defects under nutrient-replete conditions in tachyzoites. However, the growth of TgLaforin-KO tachyzoites was severely stunted when starved of glutamine, even under glucose replete conditions. The loss of TgLaforin also resulted in the attenuation of acute virulence in mice accompanied by a lower cyst burden. Defective cyst formation due to profound changes in AG morphology was also observed in TgLaforin-KO parasites, both in vitro and in vivo. Together, these data demonstrate the importance of glucan turnover across the T. gondii asexual cycle. These findings, alongside our previously identified class of small molecules that inhibit TgLaforin, implicate reversible glucan phosphorylation as a legitimate target for the development of new drugs against chronic T. gondii infections.
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Affiliation(s)
- Robert D Murphy
- Department of Microbiology, Immunology, and Molecular Genetics, College of Medicine, University of Kentucky
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky
| | - Cortni A Troublefield
- Department of Microbiology, Immunology, and Molecular Genetics, College of Medicine, University of Kentucky
| | - Joy S Miracle
- Department of Microbiology, Immunology, and Molecular Genetics, College of Medicine, University of Kentucky
| | - Lyndsay E A Young
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky
| | - Corey O Brizzee
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky
| | - Animesh Dhara
- Department of Microbiology, Immunology, and Molecular Genetics, College of Medicine, University of Kentucky
| | - Ramon C Sun
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky
| | - Craig W Vander Kooi
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky
| | - Matthew S Gentry
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky
| | - Anthony P Sinai
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky
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6
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Xu R, Beatty WL, Greigert V, Witola WH, Sibley LD. Multiple pathways for glucose phosphate transport and utilization support growth of Cryptosporidium parvum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.27.546703. [PMID: 37425855 PMCID: PMC10327089 DOI: 10.1101/2023.06.27.546703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Cryptosporidium parvum is an obligate intracellular parasite with a highly reduced mitochondrion that lacks the TCA cycle and the ability to generate ATP, making the parasite reliant on glycolysis. Genetic ablation experiments demonstrated that neither of the two putative glucose transporters CpGT1 and CpGT2 were essential for growth. Surprisingly, hexokinase was also dispensable for parasite growth while the downstream enzyme aldolase was required, suggesting the parasite has an alternative way of obtaining phosphorylated hexose. Complementation studies in E. coli support a role for direct transport of glucose-6-phosphate from the host cell by the parasite transporters CpGT1 and CpGT2, thus bypassing a requirement for hexokinase. Additionally, the parasite obtains phosphorylated glucose from amylopectin stores that are released by the action of the essential enzyme glycogen phosphorylase. Collectively, these findings reveal that C. parvum relies on multiple pathways to obtain phosphorylated glucose both for glycolysis and to restore carbohydrate reserves.
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Affiliation(s)
- Rui Xu
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Wandy L. Beatty
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Valentin Greigert
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - William H. Witola
- Department of Pathobiology, University of Illinois Urbana-Champaign, Urbana, IL 61802, USA
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
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7
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dos Santos DA, Souza HFS, Silber AM, de Souza TDACB, Ávila AR. Protein kinases on carbon metabolism: potential targets for alternative chemotherapies against toxoplasmosis. Front Cell Infect Microbiol 2023; 13:1175409. [PMID: 37287468 PMCID: PMC10242022 DOI: 10.3389/fcimb.2023.1175409] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/02/2023] [Indexed: 06/09/2023] Open
Abstract
The apicomplexan parasite Toxoplasma gondii is the causative agent of toxoplasmosis, a global disease that significantly impacts human health. The clinical manifestations are mainly observed in immunocompromised patients, including ocular damage and neuronal alterations leading to psychiatric disorders. The congenital infection leads to miscarriage or severe alterations in the development of newborns. The conventional treatment is limited to the acute phase of illness, without effects in latent parasites; consequently, a cure is not available yet. Furthermore, considerable toxic effects and long-term therapy contribute to high treatment abandonment rates. The investigation of exclusive parasite pathways would provide new drug targets for more effective therapies, eliminating or reducing the side effects of conventional pharmacological approaches. Protein kinases (PKs) have emerged as promising targets for developing specific inhibitors with high selectivity and efficiency against diseases. Studies in T. gondii have indicated the presence of exclusive PKs without homologs in human cells, which could become important targets for developing new drugs. Knockout of specific kinases linked to energy metabolism have shown to impair the parasite development, reinforcing the essentiality of these enzymes in parasite metabolism. In addition, the specificities found in the PKs that regulate the energy metabolism in this parasite could bring new perspectives for safer and more efficient therapies for treating toxoplasmosis. Therefore, this review provides an overview of the limitations for reaching an efficient treatment and explores the role of PKs in regulating carbon metabolism in Toxoplasma, discussing their potential as targets for more applied and efficient pharmacological approaches.
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Affiliation(s)
| | - Higo Fernando Santos Souza
- Laboratory of Biochemistry of Trypanosomes (LabTryp), Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Ariel M. Silber
- Laboratory of Biochemistry of Trypanosomes (LabTryp), Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | | | - Andréa Rodrigues Ávila
- Laboratório de Pesquisa em Apicomplexa, Instituto Carlos Chagas, Fiocruz, Curitiba, Brazil
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Romano JD, Mayoral J, Guevara RB, Rivera-Cuevas Y, Carruthers VB, Weiss LM, Coppens I. Toxoplasma gondii scavenges mammalian host organelles through the usurpation of host ESCRT-III and Vps4A. J Cell Sci 2023; 136:jcs260159. [PMID: 36718630 PMCID: PMC10022688 DOI: 10.1242/jcs.260159] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 01/19/2023] [Indexed: 02/01/2023] Open
Abstract
Intracellular pathogens exploit cellular resources through host cell manipulation. Within its nonfusogenic parasitophorous vacuole (PV), Toxoplasma gondii targets host nutrient-filled organelles and sequesters them into the PV through deep invaginations of the PV membrane (PVM) that ultimately detach from this membrane. Some of these invaginations are generated by an intravacuolar network (IVN) of parasite-derived tubules attached to the PVM. Here, we examined the usurpation of host ESCRT-III and Vps4A by the parasite to create PVM buds and vesicles. CHMP4B associated with the PVM/IVN, and dominant-negative (DN) CHMP4B formed many long PVM invaginations containing CHMP4B filaments. These invaginations were shorter in IVN-deficient parasites, suggesting cooperation between the IVN and ESCRT. In infected cells expressing Vps4A-DN, enlarged intra-PV structures containing host endolysosomes accumulated, reflecting defects in PVM scission. Parasite mutants lacking T. gondii (Tg)GRA14 or TgGRA64, which interact with ESCRT, reduced CHMP4B-DN-induced PVM invaginations and intra-PV host organelles, with greater defects in a double knockout, revealing the exploitation of ESCRT to scavenge host organelles by Toxoplasma.
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Affiliation(s)
- Julia D. Romano
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Joshua Mayoral
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Rebekah B. Guevara
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Yolanda Rivera-Cuevas
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Vern B. Carruthers
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Louis M. Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
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Holzer I, Desiatkina O, Anghel N, Johns SK, Boubaker G, Hemphill A, Furrer J, Păunescu E. Synthesis and Antiparasitic Activity of New Trithiolato-Bridged Dinuclear Ruthenium(II)-arene-carbohydrate Conjugates. Molecules 2023; 28:902. [PMID: 36677958 PMCID: PMC9865825 DOI: 10.3390/molecules28020902] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Eight novel carbohydrate-tethered trithiolato dinuclear ruthenium(II)-arene complexes were synthesized using CuAAC ‘click’ (Cu(I)-catalyzed azide-alkyne cycloaddition) reactions, and there in vitro activity against transgenic T. gondii tachyzoites constitutively expressing β-galactosidase (T. gondii β-gal) and in non-infected human foreskin fibroblasts, HFF, was determined at 0.1 and 1 µM. When evaluated at 1 µM, seven diruthenium-carbohydrate conjugates strongly impaired parasite proliferation by >90%, while HFF viability was retained at 50% or more, and they were further subjected to the half-maximal inhibitory concentration (IC50) measurement on T. gondii β-gal. Results revealed that the biological activity of the hybrids was influenced both by the nature of the carbohydrate (glucose vs. galactose) appended on ruthenium complex and the type/length of the linker between the two units. 23 and 26, two galactose-based diruthenium conjugates, exhibited low IC50 values and reduced effect on HFF viability when applied at 2.5 µM (23: IC50 = 0.032 µM/HFF viability 92% and 26: IC50 = 0.153 µM/HFF viability 97%). Remarkably, compounds 23 and 26 performed significantly better than the corresponding carbohydrate non-modified diruthenium complexes, showing that this type of conjugates are a promising approach for obtaining new antiparasitic compounds with reduced toxicity.
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Affiliation(s)
- Isabelle Holzer
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Oksana Desiatkina
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Nicoleta Anghel
- Institute of Parasitology Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, 3012 Bern, Switzerland
| | - Serena K. Johns
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
- School of Chemistry, Cardiff University, Park Place, Cardiff CF103AT, UK
| | - Ghalia Boubaker
- Institute of Parasitology Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, 3012 Bern, Switzerland
| | - Andrew Hemphill
- Institute of Parasitology Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, 3012 Bern, Switzerland
| | - Julien Furrer
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Emilia Păunescu
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
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Wang JL, Li TT, Elsheikha HM, Liang QL, Zhang ZW, Wang M, Sibley LD, Zhu XQ. The protein phosphatase 2A holoenzyme is a key regulator of starch metabolism and bradyzoite differentiation in Toxoplasma gondii. Nat Commun 2022; 13:7560. [PMID: 36476594 PMCID: PMC9729606 DOI: 10.1038/s41467-022-35267-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 11/22/2022] [Indexed: 12/12/2022] Open
Abstract
Phenotypic switching between tachyzoite and bradyzoite is the fundamental mechanism underpinning the pathogenicity and adaptability of the protozoan parasite Toxoplasma gondii. Although accumulation of cytoplasmic starch granules is a hallmark of the quiescent bradyzoite stage, the regulatory factors and mechanisms contributing to amylopectin storage in bradyzoites are incompletely known. Here, we show that T. gondii protein phosphatase 2A (PP2A) holoenzyme is composed of a catalytic subunit PP2A-C, a scaffold subunit PP2A-A and a regulatory subunit PP2A-B. Disruption of any of these subunits increased starch accumulation and blocked the tachyzoite-to-bradyzoite differentiation. PP2A contributes to the regulation of amylopectin metabolism via dephosphorylation of calcium-dependent protein kinase 2 at S679. Phosphoproteomics identified several putative PP2A holoenzyme substrates that are involved in bradyzoite differentiation. Our findings provide novel insight into the role of PP2A as a key regulator of starch metabolism and bradyzoite differentiation in T. gondii.
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Affiliation(s)
- Jin-Lei Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, People's Republic of China.
| | - Ting-Ting Li
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, People's Republic of China
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Qin-Li Liang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, People's Republic of China
| | - Zhi-Wei Zhang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, People's Republic of China
| | - Meng Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, People's Republic of China
| | - L David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Xing-Quan Zhu
- Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, People's Republic of China.
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11
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Keroack CD, Duraisingh MT. Molecular mechanisms of cellular quiescence in apicomplexan parasites. Curr Opin Microbiol 2022; 70:102223. [PMID: 36274498 DOI: 10.1016/j.mib.2022.102223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 01/25/2023]
Abstract
Quiescence is a reversible nonproliferative cellular state that allows organisms to persist through unfavorable conditions. Quiescence can be stimulated by a wide range of external or intrinsic factors. Cells undergo a coordinated molecular program to enter and exit from the quiescent state, which is governed by signaling, transcriptional and translational changes, epigenetic mechanisms, metabolic switches, and changes in cellular architecture. These mechanisms have been extensively studied in model organisms, and a growing number of studies have identified conserved mechanisms in apicomplexan parasites. Quiescence in the context of a parasitic infection has significant clinical impact: quiescent forms may underlie treatment failures, relapsing infections, and stress tolerance. Here, we review the latest understanding of quiescence in apicomplexa, synthesizing these studies to highlight conserved mechanisms, and identifying technologies to assist in further characterization of quiescence. Understanding conserved mechanisms of quiescence in apicomplexans will provide avenues for transmission prevention and radical cure of infections.
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12
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Dissection of Besnoitia besnoiti intermediate host life cycle stages: From morphology to gene expression. PLoS Pathog 2022; 18:e1010955. [DOI: 10.1371/journal.ppat.1010955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 12/01/2022] [Accepted: 10/27/2022] [Indexed: 11/18/2022] Open
Abstract
Cyst-forming Apicomplexa (CFA) of the Sarcocystidae have a ubiquitous presence as pathogens of humans and farm animals transmitted through the food chain between hosts with few notable exceptions. The defining hallmark of this family of obligate intracellular protists consists of their ability to remain for very long periods as infectious tissue cysts in chronically infected intermediate hosts. Nevertheless, each closely related species has evolved unique strategies to maintain distinct reservoirs on global scales and ensuring efficient transmission to definitive hosts as well as between intermediate hosts. Here, we present an in-depth comparative mRNA expression analysis of the tachyzoite and bradyzoite stages of Besnoitia besnoiti strain Lisbon14 isolated from an infected farm animal based on its annotated genome sequence. The B. besnoiti genome is highly syntenic with that of other CFA and also retains the capacity to encode a large majority of known and inferred factors essential for completing a sexual cycle in a yet unknown definitive host. This work introduces Besnoitia besnoiti as a new model for comparative biology of coccidian tissue cysts which can be readily obtained in high purity. This model provides a framework for addressing fundamental questions about the evolution of tissue cysts and the biology of this pharmacologically intractable infectious parasite stage.
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13
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Murphy RD, Chen T, Lin J, He R, Wu L, Pearson CR, Sharma S, Vander Kooi CD, Sinai AP, Zhang ZY, Vander Kooi CW, Gentry MS. The Toxoplasma glucan phosphatase TgLaforin utilizes a distinct functional mechanism that can be exploited by therapeutic inhibitors. J Biol Chem 2022; 298:102089. [PMID: 35640720 PMCID: PMC9254107 DOI: 10.1016/j.jbc.2022.102089] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/21/2022] [Accepted: 05/23/2022] [Indexed: 01/19/2023] Open
Abstract
Toxoplasma gondii is an intracellular parasite that generates amylopectin granules (AGs), a polysaccharide associated with bradyzoites that define chronic T. gondii infection. AGs are postulated to act as an essential energy storage molecule that enable bradyzoite persistence, transmission, and reactivation. Importantly, reactivation can result in the life-threatening symptoms of toxoplasmosis. T. gondii encodes glucan dikinase and glucan phosphatase enzymes that are homologous to the plant and animal enzymes involved in reversible glucan phosphorylation and which are required for efficient polysaccharide degradation and utilization. However, the structural determinants that regulate reversible glucan phosphorylation in T. gondii are unclear. Herein, we define key functional aspects of the T. gondii glucan phosphatase TgLaforin (TGME49_205290). We demonstrate that TgLaforin possesses an atypical split carbohydrate-binding-module domain. AlphaFold2 modeling combined with hydrogen-deuterium exchange mass spectrometry and differential scanning fluorimetry also demonstrate the unique structural dynamics of TgLaforin with regard to glucan binding. Moreover, we show that TgLaforin forms a dual specificity phosphatase domain-mediated dimer. Finally, the distinct properties of the glucan phosphatase catalytic domain were exploited to identify a small molecule inhibitor of TgLaforin catalytic activity. Together, these studies define a distinct mechanism of TgLaforin activity, opening up a new avenue of T. gondii bradyzoite biology as a therapeutic target.
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Affiliation(s)
- Robert D Murphy
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, Kentucky, USA; Department of Microbiology, Immunology, and Molecular Genetics, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Tiantian Chen
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Jianping Lin
- Departments of Medicinal Chemistry and Molecular Pharmacology and of Chemistry, Purdue Institute for Drug Discovery, Purdue University, West Lafayette, Indiana, USA
| | - Rongjun He
- Departments of Medicinal Chemistry and Molecular Pharmacology and of Chemistry, Purdue Institute for Drug Discovery, Purdue University, West Lafayette, Indiana, USA
| | - Li Wu
- Departments of Medicinal Chemistry and Molecular Pharmacology and of Chemistry, Purdue Institute for Drug Discovery, Purdue University, West Lafayette, Indiana, USA
| | - Caden R Pearson
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Savita Sharma
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Carl D Vander Kooi
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Anthony P Sinai
- Department of Microbiology, Immunology, and Molecular Genetics, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Zhong-Yin Zhang
- Departments of Medicinal Chemistry and Molecular Pharmacology and of Chemistry, Purdue Institute for Drug Discovery, Purdue University, West Lafayette, Indiana, USA.
| | - Craig W Vander Kooi
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, Kentucky, USA.
| | - Matthew S Gentry
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, Kentucky, USA.
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14
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Yang J, He Z, Chen C, Zhao J, Fang R. Starch Branching Enzyme 1 Is Important for Amylopectin Synthesis and Cyst Reactivation in Toxoplasma gondii. Microbiol Spectr 2022; 10:e0189121. [PMID: 35446124 PMCID: PMC9241709 DOI: 10.1128/spectrum.01891-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 03/28/2022] [Indexed: 11/21/2022] Open
Abstract
Toxoplasma gondii (T. gondii) bradyzoites facilitate chronic infections that evade host immune response. Furthermore, reactivation in immunocompromised individuals causes severe toxoplasmosis. The presence of abundant granules containing the branched starch amylopectin is major characteristic of bradyzoites that is nearly absent from tachyzoites that drive acute disease. T. gondii genome encodes to potential Starch branching enzyme 1 (SBE1) that creates branching during amylopectin biosynthesis. However, the physiological function of the amylopectin in T. gondii remains unclear. In this study, we generated a SBE1 knockout parasites and revealed that deletion of SBE1 caused amylopectin synthesis defects while having no significant impact on the growth of tachyzoites under normal culture conditions in vitro as well as virulence and brain cyst formation. Nevertheless, SBE1 knockout decreased the influx of exogenous glucose and reduced tachyzoites proliferation in nutrition-deficient conditions. Deletion of SBE1 together with the α-amylase (α-AMY), responsible for starch digestion, abolished amylopectin production and attenuated virulence while restoring brain cyst formation. In addition, cysts with defective amylopectin metabolism showed abnormal morphology and were avirulent to mice. In conclusion, SBE1 is essential for the synthesis of amylopectin, which serves as energy storage during the development and reactivation of bradyzoites. IMPORTANCE Toxoplasmosis has become a global, serious public health problem due to the extensiveness of the host. There are great differences in the energy metabolism in the different stages of infection. The most typical difference is the abundant accumulation of amylopectin granules in bradyzoites, which is almost absent in tachyzoites. Until now, the physiological functions of amylopectin have not been clearly elucidated. We focused on starch branching enzyme 1 (SBE1) in the synthesis pathway to reveal the exact physiological significance of amylopectin. Our study clarified the role of SBE1 in the synthesis pathway and amylopectin in tachyzoites and bradyzoites, and demonstrated that amylopectin, as an important carbon source, was critical to parasites growth under an unfavorable environment and the reactivation of bradyzoites to tachyzoites. The findings obtained from our study provides a new avenue for the development of Toxoplasma vaccines and anti-chronic toxoplasmosis drugs.
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Affiliation(s)
- Jing Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- College of Veterinary Medicine, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Zhengming He
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Chengjie Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Junlong Zhao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Rui Fang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
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15
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Quach EV, Cao B, Babacarkhial E, Ho D, Sharma J, Guiton PS. Phosphoglucomutase 1 contributes to optimal cyst development in Toxoplasma gondii. BMC Res Notes 2022; 15:188. [PMID: 35597992 PMCID: PMC9123713 DOI: 10.1186/s13104-022-06073-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 05/11/2022] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Toxoplasma gondii is a ubiquitous parasite of medical and veterinary importance; however, there exists no cure for chronic toxoplasmosis. Metabolic enzymes required for the production and maintenance of tissue cysts represent promising targets for novel therapies. Here, we use reverse genetics to investigate the role of Toxoplasma phosphoglucomutase 1, PGM1, in Toxoplasma growth and cystogenesis. RESULTS We found that disruption of pgm1 did not significantly affect Toxoplasma intracellular growth and the lytic cycle. pgm1-defective parasites could differentiate into bradyzoites and produced cysts containing amylopectin in vitro. However, cysts produced in the absence of pgm1 were significantly smaller than wildtype. Together, our findings suggest that PGM1 is dispensable for in vitro growth but contributes to optimal Toxoplasma cyst development in vitro, thereby necessitating further investigation into the function of this enzyme in Toxoplasma persistence in its host.
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Affiliation(s)
- Emily V Quach
- Department of Biology, Laney College, Oakland, CA, USA
| | - Binh Cao
- School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Edres Babacarkhial
- Department of Biological Sciences, California State University East Bay, Hayward, CA, USA
| | - Daniel Ho
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Janak Sharma
- Department of Biological Sciences, California State University East Bay, Hayward, CA, USA
| | - Pascale S Guiton
- Department of Biological Sciences, California State University East Bay, Hayward, CA, USA.
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16
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Ybañez RH, Nishikawa Y. Comparative Performance of Recombinant GRA6, GRA7, and GRA14 for the Serodetection of T. gondii Infection and Analysis of IgG Subclasses in Human Sera from the Philippines. Pathogens 2022; 11:pathogens11020277. [PMID: 35215219 PMCID: PMC8874886 DOI: 10.3390/pathogens11020277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/09/2022] [Accepted: 02/18/2022] [Indexed: 11/16/2022] Open
Abstract
Highly specific and sensitive diagnostic methods are vital for the effective control and treatment of toxoplasmosis. Routine diagnosis is primarily serological because T. gondii infections stimulate persistently high IgG antibody responses. The sensitivity and specificity of methods are crucial factors for the proper diagnosis of toxoplasmosis, primarily dependent on the antigens used in different assays. In the present study, we compared the serodiagnostic performances of three recombinant dense granule antigens, namely, the GRA6, GRA7, and GRA14, to detect IgG antibodies against T. gondii in human sera from the Philippines. Moreover, we evaluated the IgG1, IgG2, IgG3, and IgG4 responses against the different recombinant antigens, which has not been performed previously. Our results revealed that the TgGRA7 has consistently displayed superior diagnostic capability, while TgGRA6 can be a satisfactory alternative antigen among the GRA proteins. Furthermore, IgG1 is the predominant subclass stimulated by the different recombinant antigens. This study's results provide options to researchers and manufacturers to choose recombinant antigens suitable for their purpose.
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Affiliation(s)
- Rochelle Haidee Ybañez
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan;
- Institute of Molecular Parasitology and Protozoan Diseases, Main Campus and College of Veterinary Medicine, Barili Campus, Cebu Technological University, Cebu City 6000, Philippines
| | - Yoshifumi Nishikawa
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan;
- Correspondence:
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17
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Correa Leite PE, de Araujo Portes J, Pereira MR, Russo FB, Martins-Duarte ES, Almeida Dos Santos N, Attias M, Barrantes FJ, Baleeiro Beltrão-Braga PC, de Souza W. Morphological and biochemical repercussions of Toxoplasma gondii infection in a 3D human brain neurospheres model. Brain Behav Immun Health 2021; 11:100190. [PMID: 34589727 PMCID: PMC8474451 DOI: 10.1016/j.bbih.2020.100190] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 12/06/2020] [Indexed: 12/19/2022] Open
Abstract
Background Toxoplasmosis is caused by the parasite Toxoplasma gondii that can infect the central nervous system (CNS), promoting neuroinflammation, neuronal loss, neurotransmitter imbalance and behavioral alterations. T. gondii infection is also related to neuropsychiatric disorders such as schizophrenia. The pathogenicity and inflammatory response in rodents are different to the case of humans, compromising the correlation between the behavioral alterations and physiological modifications observed in the disease. In the present work we used BrainSpheres, a 3D CNS model derived from human pluripotent stem cells (iPSC), to investigate the morphological and biochemical repercussions of T. gondii infection in human neural cells. Methods We evaluated T. gondii ME49 strain proliferation and cyst formation in both 2D cultured human neural cells and BrainSpheres. Aspects of cell morphology, ultrastructure, viability, gene expression of neural phenotype markers, as well as secretion of inflammatory mediators were evaluated for 2 and 4 weeks post infection in BrainSpheres. Results T. gondii can infect BrainSpheres, proliferating and inducing cysts formation, neural cell death, alteration in neural gene expression and triggering the release of several inflammatory mediators. Conclusions BrainSpheres reproduce many aspects of T. gondii infection in human CNS, constituting a useful model to study the neurotoxicity and neuroinflammation mediated by the parasite. In addition, these data could be important for future studies aiming at better understanding possible correlations between psychiatric disorders and human CNS infection with T. gondii. T. gondii infects, proliferates and induce cysts formation in neurospheres. T. gondii infection induces neural cell death in neurospheres. T. gondii infection promotes alteration in neural gene expression in neurospheres. T. gondii infection promotes release of inflammatory mediators in neurospheres.
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Affiliation(s)
- Paulo Emilio Correa Leite
- Institute of Biophysics Carlos Chagas Filho and National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, RJ, Brazil.,Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque de Caxias, RJ, Brazil
| | - Juliana de Araujo Portes
- Institute of Biophysics Carlos Chagas Filho and National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, RJ, Brazil
| | | | - Fabiele Baldino Russo
- Laboratory of Disease Modeling, Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, SP, Brazil
| | - Erica S Martins-Duarte
- Institute of Biophysics Carlos Chagas Filho and National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, RJ, Brazil.,Department of Parasitology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Nathalia Almeida Dos Santos
- Laboratory of Disease Modeling, Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, SP, Brazil.,Centre for Stem Cells and Regenerative Medicine, King's College London, Guy's Hospital, London, UK
| | - Marcia Attias
- Institute of Biophysics Carlos Chagas Filho and National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, RJ, Brazil
| | - Francisco J Barrantes
- Laboratory of Molecular Neurobiology, Institute for Biomedical Research (BIOMED), UCA-CONICET, Buenos Aires, Argentina
| | - Patricia Cristina Baleeiro Beltrão-Braga
- Laboratory of Disease Modeling, Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, SP, Brazil.,Scientific Platform Pasteur-USP, São Paulo, SP, Brazil
| | - Wanderley de Souza
- Institute of Biophysics Carlos Chagas Filho and National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, RJ, Brazil
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18
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Ralton JE, Sernee MF, McConville MJ. Evolution and function of carbohydrate reserve biosynthesis in parasitic protists. Trends Parasitol 2021; 37:988-1001. [PMID: 34266735 DOI: 10.1016/j.pt.2021.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/12/2021] [Accepted: 06/15/2021] [Indexed: 11/28/2022]
Abstract
Nearly all eukaryotic cells synthesize carbohydrate reserves, such as glycogen, starch, or low-molecular-weight oligosaccharides. However, a number of parasitic protists have lost this capacity while others have lost, and subsequently evolved, entirely new pathways. Recent studies suggest that retention, loss, or acquisition of these pathways in different protists is intimately linked to their lifestyle. In particular, parasites with carbohydrate reserves often establish long-lived chronic infections and/or produce environmental cysts, whereas loss of these pathways is associated with parasites that have highly proliferative and metabolically active life-cycle stages. The evolution of mannogen biosynthesis in Leishmania and related parasites indicates that these pathways have played a role in defining the host range and niches occupied by some protists.
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Affiliation(s)
- Julie E Ralton
- Department of Biochemistry and Pharmacology, University of Melbourne, Bio21 Institute of Molecular Science and Biotechnology, Parkville, Victoria 3010, Australia
| | - M Fleur Sernee
- Department of Biochemistry and Pharmacology, University of Melbourne, Bio21 Institute of Molecular Science and Biotechnology, Parkville, Victoria 3010, Australia
| | - Malcolm J McConville
- Department of Biochemistry and Pharmacology, University of Melbourne, Bio21 Institute of Molecular Science and Biotechnology, Parkville, Victoria 3010, Australia.
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19
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Lyu C, Yang X, Yang J, Hou L, Zhou Y, Zhao J, Shen B. Role of amylopectin synthesis in Toxoplasma gondii and its implication in vaccine development against toxoplasmosis. Open Biol 2021; 11:200384. [PMID: 34129780 PMCID: PMC8205521 DOI: 10.1098/rsob.200384] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Toxoplasma gondii is a ubiquitous pathogen infecting one-third of the global population. A significant fraction of toxoplasmosis cases is caused by reactivation of existing chronic infections. The encysted bradyzoites during chronic infection accumulate high levels of amylopectin that is barely present in fast-replicating tachyzoites. However, the physiological significance of amylopectin is not fully understood. Here, we identified a starch synthase (SS) that is required for amylopectin synthesis in T. gondii. Genetic ablation of SS abolished amylopectin production, reduced tachyzoite proliferation, and impaired the recrudescence of bradyzoites to tachyzoites. Disruption of the parasite Ca2+-dependent protein kinase 2 (CDPK2) was previously shown to cause massive amylopectin accumulation and bradyzoite death. Therefore, the Δcdpk2 mutant is thought to be a vaccine candidate. Notably, deleting SS in a Δcdpk2 mutant completely abolished starch accrual and restored cyst formation as well as virulence in mice. Together these results suggest that regulated amylopectin production is critical for the optimal growth, development and virulence of Toxoplasma. Not least, our data underscore a potential drawback of the Δcdpk2 mutant as a vaccine candidate as it may regain full virulence by mutating amylopectin synthesis genes like SS.
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Affiliation(s)
- Congcong Lyu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.,Key Laboratory of Preventive Medicine in Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Xuke Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.,Key Laboratory of Preventive Medicine in Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Jichao Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.,Key Laboratory of Preventive Medicine in Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Lun Hou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.,Key Laboratory of Preventive Medicine in Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Yanqin Zhou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.,Key Laboratory of Preventive Medicine in Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Junlong Zhao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.,Key Laboratory of Preventive Medicine in Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.,Hubei Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, People's Republic of China
| | - Bang Shen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.,Key Laboratory of Preventive Medicine in Hubei Province, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
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20
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Yang J, Yang C, Qian J, Li F, Zhao J, Fang R. Toxoplasma gondii α-amylase deletion mutant is a promising vaccine against acute and chronic toxoplasmosis. Microb Biotechnol 2020; 13:2057-2069. [PMID: 32959958 PMCID: PMC7533317 DOI: 10.1111/1751-7915.13668] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/20/2020] [Accepted: 09/01/2020] [Indexed: 12/25/2022] Open
Abstract
Individuals with inhibited immunity may develop lethal toxoplasmosis; thus, a safe and effective vaccine is urged to be developed. Toxoplasma gondii (T. gondii) α-amylase (α-AMY) is one of the enzymes responsible for starch digestion. In the present study, we first generated a ME49Δα-amy mutant and discovered that loss of α-AMY robustly grew in vitro but contributed to significant virulence attenuation in vivo. Therefore, we established a mouse model to explore the protective immunity of Δα-amy mutant against acute and chronic toxoplasmosis. The results indicated that the survival rates of short-term or long-term immunized mice re-infected with the tachyzoites of multiple T. gondii strains were nearly 100%. ME49Δα-amy not only could provide protective immunity against tachyzoites infection but also could resist the infection of tissue cysts. Furthermore, we detected that ME49Δα-amy vaccination could effectively eliminate the proliferation of parasites in mice and prevent the formation of cysts. The significant increases of Th1-type cytokines, Th2-type cytokines and specific total IgG and IgG subclasses (IgG2a and IgG1) confirmed efficiency of a combination of cellular and humoral immunity against infection. In conclusion, ME49Δα-amy attenuated strain can produce strong immune responses to provide efficient protection against toxoplasmosis, which signifies that ME49Δα-amy mutant may be a potential vaccine candidate.
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Affiliation(s)
- Jing Yang
- State Key Laboratory of Agricultural MicrobiologyCollege of Veterinary MedicineHuazhong Agricultural UniversityWuhanHubei430070China
| | - Chenghang Yang
- State Key Laboratory of Agricultural MicrobiologyCollege of Veterinary MedicineHuazhong Agricultural UniversityWuhanHubei430070China
| | - Jiahui Qian
- State Key Laboratory of Agricultural MicrobiologyCollege of Veterinary MedicineHuazhong Agricultural UniversityWuhanHubei430070China
| | - Facai Li
- College of Animal Science and TechnologySouthwest UniversityChongqing400715China
| | - Junlong Zhao
- State Key Laboratory of Agricultural MicrobiologyCollege of Veterinary MedicineHuazhong Agricultural UniversityWuhanHubei430070China
| | - Rui Fang
- State Key Laboratory of Agricultural MicrobiologyCollege of Veterinary MedicineHuazhong Agricultural UniversityWuhanHubei430070China
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21
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Sinai AP, Suvorova ES. The RESTRICTION checkpoint: a window of opportunity governing developmental transitions in Toxoplasma gondii. Curr Opin Microbiol 2020; 58:99-105. [PMID: 33065371 DOI: 10.1016/j.mib.2020.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 01/27/2023]
Abstract
The life cycle of Toxoplasma gondii is characterized by active replication alternating with periods of rest. Encysted dormant sporozoites and bradyzoites initiate active replication as tachyzoites and merozoites. Here we explore the role of the cell cycle with a focus on the canonical G1 RESTRICTION checkpoint (R-point) as the integrator governing developmental decisions in T. gondii. This surveillance mechanism, which licenses replication, creates a window of opportunity in G1 for cellular reorganization in the execution of developmental transitions. We also explore the unique status of the bradyzoite, the only life cycle stage executing both a forward (entry into the sexual cycle) and reverse (recrudescence) developmental transitions as a multipotent cell. These opposing decisions are executed through the common machinery of the RESTRICTION checkpoint.
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Affiliation(s)
- Anthony P Sinai
- Department of Microbiology Immunology and Molecular Genetics, University of Kentucky College of Medicine, 800 Rose Street, Lexington, KY 40536, USA
| | - Elena S Suvorova
- Department of Internal Medicine, Division of Infectious Diseases and International Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Blvd, Tampa, FL 33612, USA.
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22
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Mandalasi M, Kim HW, Thieker D, Sheikh MO, Gas-Pascual E, Rahman K, Zhao P, Daniel NG, van der Wel H, Ichikawa HT, Glushka JN, Wells L, Woods RJ, Wood ZA, West CM. A terminal α3-galactose modification regulates an E3 ubiquitin ligase subunit in Toxoplasma gondii. J Biol Chem 2020; 295:9223-9243. [PMID: 32414843 PMCID: PMC7335778 DOI: 10.1074/jbc.ra120.013792] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/14/2020] [Indexed: 12/29/2022] Open
Abstract
Skp1, a subunit of E3 Skp1/Cullin-1/F-box protein ubiquitin ligases, is modified by a prolyl hydroxylase that mediates O2 regulation of the social amoeba Dictyostelium and the parasite Toxoplasma gondii The full effect of hydroxylation requires modification of the hydroxyproline by a pentasaccharide that, in Dictyostelium, influences Skp1 structure to favor assembly of Skp1/F-box protein subcomplexes. In Toxoplasma, the presence of a contrasting penultimate sugar assembled by a different glycosyltransferase enables testing of the conformational control model. To define the final sugar and its linkage, here we identified the glycosyltransferase that completes the glycan and found that it is closely related to glycogenin, an enzyme that may prime glycogen synthesis in yeast and animals. However, the Toxoplasma enzyme catalyzes formation of a Galα1,3Glcα linkage rather than the Glcα1,4Glcα linkage formed by glycogenin. Kinetic and crystallographic experiments showed that the glycosyltransferase Gat1 is specific for Skp1 in Toxoplasma and also in another protist, the crop pathogen Pythium ultimum The fifth sugar is important for glycan function as indicated by the slow-growth phenotype of gat1Δ parasites. Computational analyses indicated that, despite the sequence difference, the Toxoplasma glycan still assumes an ordered conformation that controls Skp1 structure and revealed the importance of nonpolar packing interactions of the fifth sugar. The substitution of glycosyltransferases in Toxoplasma and Pythium by an unrelated bifunctional enzyme that assembles a distinct but structurally compatible glycan in Dictyostelium is a remarkable case of convergent evolution, which emphasizes the importance of the terminal α-galactose and establishes the phylogenetic breadth of Skp1 glycoregulation.
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Affiliation(s)
- Msano Mandalasi
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Hyun W Kim
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - David Thieker
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - M Osman Sheikh
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Elisabet Gas-Pascual
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Kazi Rahman
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Peng Zhao
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Nitin G Daniel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Hanke van der Wel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - H Travis Ichikawa
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - John N Glushka
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Lance Wells
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Robert J Woods
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Zachary A Wood
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Christopher M West
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA.
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23
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Song X, Lin M, Li M, Yang X, Liu J, Liu Q. Toxoplasma gondii metacaspase 2 is an important factor that influences bradyzoite formation in the Pru strain. Parasitol Res 2020; 119:2287-2298. [PMID: 32468190 DOI: 10.1007/s00436-020-06722-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 05/17/2020] [Indexed: 12/12/2022]
Abstract
Toxoplasma gondii is an important zoonotic protozoan of the phylum Apicomplexa that can infect nearly all warm-blooded animals. The parasite can exist as the interconvertible tachyzoite or bradyzoite forms, leading to acute or latent infection, respectively. No drug has been reported to penetrate the cyst wall and reduce bradyzoite survival and proliferation till now. The transcriptional level of metacaspases 2 (TgMCA2) in T. gondii is significantly upregulated during the formation of bradyzoites in the Pru strain, indicating that it may play an important role in the formation of bradyzoites. To further explore the function of TgMCA2, we constructed a TgMCA2 gene-knockout variant of the Pru strain (Δmca2). Comparative analysis revealed that the proliferative capacity of Pru Δmca2 increased, while the invasion and egressing properties were not affected by the knockout. Further data shows that the tachyzoites of Δmca2 failed to induce differentiation and form bradyzoites in vitro, and the transcriptional levels of some of the bradyzoite-specific genes (such as BAG1, LDH2, and SAG4A) in Δmca2 were significantly lower compared with that in the Pru strain at the bradyzoite stage. In vivo, no cysts were detected in Δmca2-infected mice. Further determination of parasite burden in Δmca2- and Pru-infected mice brain tissue at the genetic level showed that the gene load was significantly lower than that in Pru. In summary, we confirmed that TgMCA2 contributes to the formation of bradyzoites, and could provide an important foundation for the development of attenuated vaccines for the prevention of T. gondii infection.
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Affiliation(s)
- Xingju Song
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Mengyang Lin
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Muzi Li
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xu Yang
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Jing Liu
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China.
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China.
| | - Qun Liu
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China.
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China.
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24
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Guevara RB, Fox BA, Bzik DJ. Succinylated Wheat Germ Agglutinin Colocalizes with the Toxoplasma gondii Cyst Wall Glycoprotein CST1. mSphere 2020; 5:e00031-20. [PMID: 32132158 PMCID: PMC7056803 DOI: 10.1128/msphere.00031-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 02/16/2020] [Indexed: 11/20/2022] Open
Abstract
The glycosylated mucin domain of the Toxoplasma gondii cyst wall glycoprotein CST1 is heavily stained by Dolichos biflorus agglutinin, a lectin that binds to N-acetylgalactosamine. The cyst wall is also heavily stained by the chitin binding lectin succinylated wheat germ agglutinin (s-WGA), which selectively binds to N-acetylglucosamine-decorated structures. Here, we tracked the localization of N-acetylglucosamine-decorated structures that bind to s-WGA in immature and mature in vitro cysts. s-WGA localization was observed at the cyst periphery 6 h after the differentiation of the tachyzoite-stage parasitophorous vacuole. By day 1 and at all later times after differentiation, s-WGA was localized in a continuous staining pattern at the cyst wall. Coinciding with the maturation of the cyst matrix by day 3 of cyst development, s-WGA also localized in a continuous matrix pattern inside the cyst. s-WGA localized in both the outer and inner layer regions of the cyst wall and in a continuous matrix pattern inside mature 7- and 10-day-old cysts. In addition, s-WGA colocalized in the cyst wall with CST1, suggesting that N-acetylglucosamine- and N-acetylgalactosamine-decorated molecules colocalized in the cyst wall. In contrast to CST1, GRA4, and GRA6, the relative accumulation of the molecules that bind s-WGA in the cyst wall was not dependent on the expression of GRA2. Our results suggest that GRA2-dependent and GRA2-independent mechanisms regulate the trafficking and accumulation of glycosylated molecules that colocalize in the cyst wall.IMPORTANCE Chronic Toxoplasma gondii infection is maintained in the central nervous system by thick-walled cysts. If host immunity wanes, cysts recrudesce and cause severe and often lethal toxoplasmic encephalitis. Currently, there are no therapies to eliminate cysts, and little biological information is available regarding cyst structure(s). Here, we investigated cyst wall molecules recognized by succinylated wheat germ agglutinin (s-WGA), a lectin that specifically binds to N-acetylglucosamine-decorated structures. N-Acetylglucosamine regulates cell signaling and plays structural roles at the cell surface in many organisms. The cyst wall and cyst matrix were heavily stained by s-WGA in mature cysts and were differentially stained during cyst development. The relative accumulation of molecules that bind to s-WGA in the cyst wall was not dependent on the expression of GRA2. Our findings suggest that glycosylated cyst wall molecules gain access to the cyst wall via GRA2-dependent and GRA2-independent mechanisms and colocalize in the cyst wall.
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Affiliation(s)
- Rebekah B Guevara
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Barbara A Fox
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - David J Bzik
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
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25
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Cao XZ, Wang JL, Elsheikha HM, Li TT, Sun LX, Liang QL, Zhang ZW, Lin RQ. Characterization of the Role of Amylo-Alpha-1,6-Glucosidase Protein in the Infectivity of Toxoplasma gondii. Front Cell Infect Microbiol 2019; 9:418. [PMID: 31867292 PMCID: PMC6908810 DOI: 10.3389/fcimb.2019.00418] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/22/2019] [Indexed: 11/13/2022] Open
Abstract
In this study, we characterized the role of amylo-alpha-1,6-glucosidase (Aa16GL) in the biology and infectivity of Toxoplasma gondii, using Aa16GL-deficient parasites of type I RH and type II Prugniaud (Pru) strains. The subcellular localization of Aa16GL protein was characterized by tagging a 3 × HA to the 3′ end of the Aa16GL gene endogenous locus. Immunostaining of the expressed Aa16GL protein revealed that it is located in several small cytoplasmic puncta. Functional characterization of ΔAa16GL mutants using plaque assay, egress assay and intracellular replication assay showed that parasites lacking Aa16GL exhibit a slight reduction in the growth rate, but remained virulent to mice. Although PruΔAa16GL tachyzoites retained the ability to differentiate into bradyzoites in vitro, they exhibited slight reduction in their ability to form cysts in mice. These findings reveal new properties of Aa16GL and suggest that while it does not have a substantial role in mediating T. gondii infectivity, this protein can influence the formation of parasite cysts in mice.
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Affiliation(s)
- Xue-Zhen Cao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Veterinary Parasitology of Gansu Province, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou, China
| | - Jin-Lei Wang
- Key Laboratory of Veterinary Parasitology of Gansu Province, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
| | - Ting-Ting Li
- Key Laboratory of Veterinary Parasitology of Gansu Province, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Li-Xiu Sun
- Key Laboratory of Veterinary Parasitology of Gansu Province, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Qin-Li Liang
- Key Laboratory of Veterinary Parasitology of Gansu Province, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Zhi-Wei Zhang
- Key Laboratory of Veterinary Parasitology of Gansu Province, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Rui-Qing Lin
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou, China
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26
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Paredes-Santos T, Wang Y, Waldman B, Lourido S, Saeij JP. The GRA17 Parasitophorous Vacuole Membrane Permeability Pore Contributes to Bradyzoite Viability. Front Cell Infect Microbiol 2019; 9:321. [PMID: 31572690 PMCID: PMC6751312 DOI: 10.3389/fcimb.2019.00321] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 08/27/2019] [Indexed: 01/25/2023] Open
Abstract
The Toxoplasma gondii parasitophorous vacuole membrane (PVM) offers protection from the host immune system but is also a barrier for uptake of nutrients from the host. Previously, we showed that GRA17 mediates the tachyzoite PVM permeability to small molecules. During the conversion from tachyzoites to encysted bradyzoites, the PVM become the cyst membrane that is the outer layer of the cyst wall. Little is known about how small molecules, such as nutrients, enter cysts. To characterize GRA17's role in cysts, we deleted GRA17 in the type II ME49 cyst-forming strain. ME49Δgra17 parasites have reduced growth and formed grossly enlarged "bubble vacuoles," which have reduced PVM small molecule permeability. ME49Δgra17 parasites formed cysts in vitro at rates comparable to the wild-type, but the viability of the bradyzoites inside these cysts was significantly reduced compared to wild-type bradyzoites. Genetic complementation of ME49Δgra17 with GRA17 expressed from the endogenous or tachyzoite-specific SAG1 promoter recovered the viability of bradyzoites. Complementation with the bradyzoite-specific SRS9 promoter drastically increased the viability of bradyzoites, demonstrating the importance of GRA17 in regulating bradyzoite viability inside cysts. Mice infected with a high dose of ME49Δgra17 parasites did not contain parasites in their brain nor did mice infected with ME49Δgra17 complemented with GRA17 expressed from a bradyzoite-specific promoter. Our results suggest that the ME49Δgra17 strain is avirulent and is cleared before it can reach the brain and that GRA17 not only plays an important role during acute infections but is also needed for viability of bradyzoites inside cysts.
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Affiliation(s)
- Tatiana Paredes-Santos
- Department of Pathology, Microbiology and Immunology, University of California, Davis, Davis, CA, United States
| | - Yifan Wang
- Department of Pathology, Microbiology and Immunology, University of California, Davis, Davis, CA, United States
| | - Benjamin Waldman
- Whitehead Institute for Biomedical Research, Cambridge, MA, United States
| | - Sebastian Lourido
- Whitehead Institute for Biomedical Research, Cambridge, MA, United States
- Biology Department, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Jeroen P. Saeij
- Department of Pathology, Microbiology and Immunology, University of California, Davis, Davis, CA, United States
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27
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Pyruvate Homeostasis as a Determinant of Parasite Growth and Metabolic Plasticity in Toxoplasma gondii. mBio 2019; 10:mBio.00898-19. [PMID: 31186321 PMCID: PMC6561023 DOI: 10.1128/mbio.00898-19] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii is a widespread intracellular pathogen infecting humans and a variety of animals. Previous studies have shown that Toxoplasma uses glucose and glutamine as the main carbon sources to support asexual reproduction, but neither nutrient is essential. Such metabolic flexibility may allow it to survive within diverse host cell types. Here, by focusing on the glycolytic enzyme pyruvate kinase (PYK) that converts phosphoenolpyruvate (PEP) into pyruvate, we found that Toxoplasma can also utilize lactate and alanine. We show that catabolism of all indicated carbon sources converges at pyruvate, and maintaining a constant pyruvate supply is critical to parasite growth. Toxoplasma expresses two PYKs: PYK1 in the cytosol and PYK2 in the apicoplast (a chloroplast relict). Genetic deletion of PYK2 did not noticeably affect parasite growth and virulence, which contrasts with the current model of carbon metabolism in the apicoplast. On the other hand, PYK1 was refractory to disruption. Conditional depletion of PYK1 resulted in global alteration of carbon metabolism, amylopectin accumulation, and reduced cellular ATP, leading to severe growth impairment. Notably, the attenuated growth of the PYK1-depleted mutant was partially rescued by lactate or alanine supplementation, and rescue by lactate required lactate dehydrogenase activity to convert it to pyruvate. Moreover, depletion of PYK1 in conjunction with PYK2 ablation led to accentuated loss of apicoplasts and complete growth arrest. Together, our results underline a critical role of pyruvate homeostasis in determining the metabolic flexibility and apicoplast maintenance, and they significantly extend our current understanding of carbon metabolism in T. gondii IMPORTANCE Toxoplasma gondii infects almost all warm-blooded animals, and metabolic flexibility is deemed critical for its successful parasitism in diverse hosts. Glucose and glutamine are the major carbon sources to support parasite growth. In this study, we found that Toxoplasma is also competent in utilizing lactate and alanine and, thus, exhibits exceptional metabolic versatility. Notably, all these nutrients need to be converted to pyruvate to fuel the lytic cycle, and achieving a continued pyruvate supply is vital to parasite survival and metabolic flexibility. Although pyruvate can be generated by two distinct pyruvate kinases, located in cytosol and apicoplast, respectively, the cytosolic enzyme is the main source of subcellular pyruvate, and cooperative usage of pyruvate among multiple organelles is critical for parasite growth and virulence. These findings expand our current understanding of carbon metabolism in Toxoplasma gondii and related parasites while providing a basis for designing novel antiparasitic interventions.
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28
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Xia N, Yang J, Ye S, Zhang L, Zhou Y, Zhao J, David Sibley L, Shen B. Functional analysis of Toxoplasma lactate dehydrogenases suggests critical roles of lactate fermentation for parasite growth in vivo. Cell Microbiol 2017; 20. [PMID: 29028143 DOI: 10.1111/cmi.12794] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 09/25/2017] [Accepted: 10/04/2017] [Indexed: 12/20/2022]
Abstract
Glycolysis was thought to be the major pathway of energy supply in both fast-replicating tachyzoites and slowly growing bradyzoites of Toxoplasma gondii. However, its biological significance has not been clearly verified. The genome of T. gondii encodes two lactate dehydrogenases (LDHs), which are differentially expressed in tachyzoites and bradyzoites. In this study, we knocked out the two LDH genes individually and in combination and found that neither gene was required for tachyzoite growth in vitro under standard growth conditions. However, during infection in mice, Δldh1 and Δldh1 Δldh2 mutants were unable to propagate and displayed significant virulence attenuation and cyst formation defects. LDH2 only played minor roles in these processes. To further elucidate the mechanisms underlying the critical requirement of LDH in vivo, we found that Δldh1 Δldh2 mutants replicated significantly more slowly than wild-type parasites when cultured under conditions with physiological levels of oxygen (3%). In addition, Δldh1 Δldh2 mutants were more susceptible to the oxidative phosphorylation inhibitor oligomycin A. Together these results suggest that lactate fermentation is critical for parasite growth under physiological conditions, likely because energy production from oxidative phosphorylation is insufficient when oxygen is limited and lactate fermentation becomes a key supplementation.
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Affiliation(s)
- Ningbo Xia
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Jichao Yang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Shu Ye
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Lihong Zhang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yanqin Zhou
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Junlong Zhao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China.,Hubei Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China.,Key Laboratory of Preventive Medicine in Hubei Province, Wuhan, Hubei, China
| | - Laurence David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Bang Shen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China.,Key Laboratory of Preventive Medicine in Hubei Province, Wuhan, Hubei, China
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29
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Sinai AP, Watts EA, Dhara A, Murphy RD, Gentry MS, Patwardhan A. Reexamining Chronic Toxoplasma gondii Infection: Surprising Activity for a "Dormant" Parasite. CURRENT CLINICAL MICROBIOLOGY REPORTS 2016; 3:175-185. [PMID: 28191447 PMCID: PMC5295825 DOI: 10.1007/s40588-016-0045-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE OF REVIEW Despite over a third of the world's population being chronically infected with Toxoplasma gondii, little is known about this largely asymptomatic phase of infection. This stage is mediated in vivo by bradyzoites within tissue cysts. The absence of overt symptoms has been attributed to the dormancy of bradyzoites. In this review, we reexamine the conventional view of chronic toxoplasmosis in light of emerging evidence challenging both the nature of dormancy and the consequences of infection in the CNS. RECENT FINDINGS New and emerging data reveal a previously unrecognized level of physiological and replicative capacity of bradyzoites within tissue cysts. These findings have emerged in the context of a reexamination of the chronic infection in the brain that correlates with changes in neuronal architecture, neurochemistry, and behavior that suggest that the chronic infection is not without consequence. SUMMARY The emerging data driven by the development of new approaches to study the progression of chronic toxoplasma infection reveals significant physiological and replicative capacity for what has been viewed as a dormant state. The emergence of bradyzoite and tissue cyst biology from what was viewed as a physiological "black box" offers exciting new areas for investigation with direct implications on the approaches to drug development targeting this drug-refractory state. In addition, new insights from studies on the neurobiology on chronic infection reveal a complex and dynamic interplay between the parasite, brain microenvironment, and the immune response that results in the detente that promotes the life-long persistence of the parasite in the host.
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Affiliation(s)
- Anthony P Sinai
- Department of Microbiology Immunology and Molecular Genetics, Lexington, KY, USA
| | - Elizabeth A Watts
- Department of Microbiology Immunology and Molecular Genetics, Lexington, KY, USA
| | - Animesh Dhara
- Department of Microbiology Immunology and Molecular Genetics, Lexington, KY, USA
| | - Robert D Murphy
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
| | - Matthew S Gentry
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
| | - Abhijit Patwardhan
- Department of Biomedical Engineering, College of Engineering, University of Kentucky, Lexington, KY 40506, USA
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30
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Xin CF, Kim HS, Sato A, Lee HJ, Lee YW, Pyo KH, Shin EH. In vitro inhibition of Toxoplasma gondii by the anti-malarial candidate, 6-(1,2,6,7-tetraoxaspiro[7.11]nonadec-4-yl)hexan-1-ol. Parasitol Int 2016; 65:494-9. [PMID: 27380994 DOI: 10.1016/j.parint.2016.06.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 06/27/2016] [Accepted: 06/29/2016] [Indexed: 10/21/2022]
Abstract
An anti-malarial candidate, 6-(1,2,6,7-tetraoxaspiro[7.11]nonadec-4-yl)hexan-1-ol (N-251), was studied to characterize its potential as a novel anti-Toxoplasma gondii drug. In the present study, IC50 and LC50 of N-251 on host cells and T. gondii were compared to those of artemisinin and sulfadiazine. The IC50 on Huh-7 cells was 10.19μg/ml, 67.69μg/ml and 310.17μg/ml for N-251, artemisinin, and sulfadiazine, respectively. The LC50 for anti-T. gondii effect was shown to be 1.11μg/ml, 5.79μg/ml, and 5.45μg/ml for N-251, artemisinin and sulfadiazine, respectively. N-251 concentration causing complete parasiticidal effect with minimal cytotoxicity on host cells was determined to be 5μg/ml. Additionally, the anti-T. gondii effect of N-251 was confirmed by ultrastructural changes, loss of organelles, degenerated morphology and the increase of amylopectin as detected by transmission electron microscope (TEM). Accordingly, the present study suggests that the anti-malarial synthetic endoperoxide, N-251, is an emerging drug candidate more effective than artemisinin and sulfadiazine.
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Affiliation(s)
- Chun-Feng Xin
- Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, and Institute of Endemic Diseases, Seoul National University Medical Research Center, Seoul 110-799, Republic of Korea
| | - Hye-Sook Kim
- Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Okayama 700-8530, Japan
| | - Akira Sato
- Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Okayama 700-8530, Japan
| | - Hak-Jae Lee
- Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, and Institute of Endemic Diseases, Seoul National University Medical Research Center, Seoul 110-799, Republic of Korea
| | - You-Won Lee
- Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, and Institute of Endemic Diseases, Seoul National University Medical Research Center, Seoul 110-799, Republic of Korea
| | - Kyoung-Ho Pyo
- Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, and Institute of Endemic Diseases, Seoul National University Medical Research Center, Seoul 110-799, Republic of Korea
| | - Eun-Hee Shin
- Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, and Institute of Endemic Diseases, Seoul National University Medical Research Center, Seoul 110-799, Republic of Korea; Seoul National University Bundang Hospital, Seongnam 463-707, Republic of Korea.
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31
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Ji H, Wang J, Guo J, Li Y, Lian S, Guo W, Yang H, Kong F, Zhen L, Guo L, Liu Y. Progress in the biological function of alpha-enolase. ANIMAL NUTRITION (ZHONGGUO XU MU SHOU YI XUE HUI) 2016; 2:12-17. [PMID: 29767008 PMCID: PMC5941012 DOI: 10.1016/j.aninu.2016.02.005] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/03/2016] [Indexed: 11/25/2022]
Abstract
Alpha-enolase (ENO1), also known as 2-phospho-D-glycerate hydrolase, is a metalloenzyme that catalyzes the conversion of 2-phosphoglyceric acid to phosphoenolpyruvic acid in the glycolytic pathway. It is a multifunctional glycolytic enzyme involved in cellular stress, bacterial and fungal infections, autoantigen activities, the occurrence and metastasis of cancer, parasitic infections, and the growth, development and reproduction of organisms. This article mainly reviews the basic characteristics and biological functions of ENO1.
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Affiliation(s)
| | | | | | | | | | | | - Huanmin Yang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, China
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Almeida F, Sardinha-Silva A, da Silva TA, Pessoni AM, Pinzan CF, Alegre-Maller ACP, Cecílio NT, Moretti NS, Damásio ARL, Pedersoli WR, Mineo JR, Silva RN, Roque-Barreira MC. Toxoplasma gondii Chitinase Induces Macrophage Activation. PLoS One 2015; 10:e0144507. [PMID: 26659253 PMCID: PMC4684212 DOI: 10.1371/journal.pone.0144507] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 11/19/2015] [Indexed: 01/06/2023] Open
Abstract
Toxoplasma gondii is an obligate intracellular protozoan parasite found worldwide that is able to chronically infect almost all vertebrate species, especially birds and mammalians. Chitinases are essential to various biological processes, and some pathogens rely on chitinases for successful parasitization. Here, we purified and characterized a chitinase from T. gondii. The enzyme, provisionally named Tg_chitinase, has a molecular mass of 13.7 kDa and exhibits a Km of 0.34 mM and a Vmax of 2.64. The optimal environmental conditions for enzymatic function were at pH 4.0 and 50 °C. Tg_chitinase was immunolocalized in the cytoplasm of highly virulent T. gondii RH strain tachyzoites, mainly at the apical extremity. Tg_chitinase induced macrophage activation as manifested by the production of high levels of pro-inflammatory cytokines, a pathogenic hallmark of T. gondii infection. In conclusion, to our knowledge, we describe for the first time a chitinase of T. gondii tachyzoites and provide evidence that this enzyme might influence the pathogenesis of T. gondii infection.
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Affiliation(s)
- Fausto Almeida
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP, 14049-900, Brasil
| | - Aline Sardinha-Silva
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP, 14049-900, Brasil
| | - Thiago Aparecido da Silva
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP, 14049-900, Brasil
| | - André Moreira Pessoni
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP, 14049-900, Brasil
| | - Camila Figueiredo Pinzan
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP, 14049-900, Brasil
| | - Ana Claudia Paiva Alegre-Maller
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP, 14049-900, Brasil
| | - Nerry Tatiana Cecílio
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP, 14049-900, Brasil
| | - Nilmar Silvio Moretti
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de Sao Paulo, São Paulo, SP, Brasil
| | - André Ricardo Lima Damásio
- Departamento de Bioquímica e Biologia Tecidual, Instituto de Biologia, Universidade de Campinas, Campinas, SP, Brasil
| | - Wellington Ramos Pedersoli
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP, 14040-900, Brasil
| | - José Roberto Mineo
- Laboratorio de Imunoparasitologia, Departamento de Imunologia, Microbiologia e Parasitologia, Universidade Federal de Uberlândia, Av. Pará, 1720, Uberlândia, MG, 38400 902, Brasil
| | - Roberto Nascimento Silva
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP, 14040-900, Brasil
| | - Maria Cristina Roque-Barreira
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP, 14049-900, Brasil
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Regulation of Starch Stores by a Ca2+-Dependent Protein Kinase Is Essential for Viable Cyst Development in Toxoplasma gondii. Cell Host Microbe 2015; 18:670-81. [DOI: 10.1016/j.chom.2015.11.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 08/10/2015] [Accepted: 11/13/2015] [Indexed: 01/05/2023]
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Nascimento FS, Suzuki LA, Branco N, Franco RMB, Andrade PD, Costa SCB, Pedro MN, Rossi CL. Toxoplasma-SPECIFIC IgG SUBCLASS ANTIBODY RESPONSE IN CEREBROSPINAL FLUID SAMPLES FROM PATIENTS WITH CEREBRAL TOXOPLASMOSIS. Rev Inst Med Trop Sao Paulo 2015; 57:439-42. [PMID: 26603234 PMCID: PMC4660456 DOI: 10.1590/s0036-46652015000500013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 02/05/2015] [Indexed: 11/22/2022] Open
Abstract
Cerebral toxoplasmosis can be highly debilitating and occasionally fatal in persons with immune system deficiencies. In this study, we evaluated the Toxoplasma gondii-specific IgG subclass antibody response in 19 cerebrospinal fluid (CSF) samples from patients with cerebral toxoplasmosis who had a positive IgG anti-T. gondii ELISA standardized with a cyst antigen preparation. There were no significant differences between the rates of positivity and the antibody concentrations (arithmetic means of the ELISA absorbances, MEA) for IgG1 and IgG2, but the rates of positivity and MEA values for these two IgG subclasses were significantly higher than those for IgG3 and IgG4. The marked IgG2 response in CSF from patients with cerebral toxoplasmosis merits further investigation.
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Affiliation(s)
- Fernanda S Nascimento
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brasil
| | - Lisandra A Suzuki
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brasil
| | - Nilson Branco
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brasil
| | - Regina M B Franco
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brasil
| | - Paula D Andrade
- Departamento de Medicina Interna, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brasil
| | - Sandra C B Costa
- Departamento de Medicina Interna, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brasil
| | - Marcelo N Pedro
- Departamento de Medicina Interna, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brasil
| | - Cláudio L Rossi
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brasil
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Dogga SK, Bartošová-Sojková P, Lukeš J, Soldati-Favre D. Phylogeny, Morphology, and Metabolic and Invasive Capabilities of Epicellular Fish Coccidium Goussia janae. Protist 2015; 166:659-76. [PMID: 26599727 DOI: 10.1016/j.protis.2015.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 09/13/2015] [Accepted: 09/15/2015] [Indexed: 01/08/2023]
Abstract
To fill the knowledge gap on the biology of the fish coccidian Goussia janae, RNA extracted from exogenously sporulated oocysts was sequenced. Analysis by Trinity and Trinotate pipelines showed that 84.6% of assembled transcripts share the highest similarity with Toxoplasma gondii and Neospora caninum. Phylogenetic and interpretive analyses from RNA-seq data provide novel insight into the metabolic capabilities, composition of the invasive machinery and the phylogenetic relationships of this parasite of cold-blooded vertebrates with other coccidians. This allows re-evaluation of the phylogenetic position of G. janae and sheds light on the emergence of the highly successful obligatory intracellularity of apicomplexan parasites. G. janae possesses a partial glideosome and along with it, the metabolic capabilities and adaptions of G. janae might provide cues as to how apicomplexans adjusted to extra- or intra-cytoplasmic niches and also to become obligate intracellular parasites. Unlike the similarly localized epicellular Cryptosporidium spp., G. janae lacks the feeder organelle necessary for directly scavenging nutrients from the host. Transcriptome analysis indicates that G. janae possesses metabolic capabilities comparable to T. gondii. Additionally, this enteric coccidium might also access host cell nutrients given the presence of a recently identified gene encoding the molecular sieve at the parasitophorous vacuole membrane.
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Affiliation(s)
- Sunil Kumar Dogga
- Department of Microbiology and Molecular Medicine, University of Geneva. CMU, 1 Rue Michel-Servet, CH-1211 Geneva 4, Switzerland
| | - Pavla Bartošová-Sojková
- Institute of Parasitology, Biology Centre, Branišovská 31, České Budějovice (Budweis), Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Branišovská 31, České Budějovice (Budweis), Czech Republic; Faculty of Science, University of South Bohemia, Branišovská 1645/31A, České Budějovice (Budweis), Czech Republic; Canadian Institute for Advanced Research, 180 Dundas St W, Toronto, ON M5G 1Z8, Canada
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University of Geneva. CMU, 1 Rue Michel-Servet, CH-1211 Geneva 4, Switzerland.
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Ruan J, Mouveaux T, Light SH, Minasov G, Anderson WF, Tomavo S, Ngô HM. The structure of bradyzoite-specific enolase from Toxoplasma gondii reveals insights into its dual cytoplasmic and nuclear functions. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:417-26. [PMID: 25760592 PMCID: PMC4356359 DOI: 10.1107/s1399004714026479] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 12/01/2014] [Indexed: 12/15/2022]
Abstract
In addition to catalyzing a central step in glycolysis, enolase assumes a remarkably diverse set of secondary functions in different organisms, including transcription regulation as documented for the oncogene c-Myc promoter-binding protein 1. The apicomplexan parasite Toxoplasma gondii differentially expresses two nuclear-localized, plant-like enolases: enolase 1 (TgENO1) in the latent bradyzoite cyst stage and enolase 2 (TgENO2) in the rapidly replicative tachyzoite stage. A 2.75 Å resolution crystal structure of bradyzoite enolase 1, the second structure to be reported of a bradyzoite-specific protein in Toxoplasma, captures an open conformational state and reveals that distinctive plant-like insertions are located on surface loops. The enolase 1 structure reveals that a unique residue, Glu164, in catalytic loop 2 may account for the lower activity of this cyst-stage isozyme. Recombinant TgENO1 specifically binds to a TTTTCT DNA motif present in the cyst matrix antigen 1 (TgMAG1) gene promoter as demonstrated by gel retardation. Furthermore, direct physical interactions of both nuclear TgENO1 and TgENO2 with the TgMAG1 gene promoter are demonstrated in vivo using chromatin immunoprecipitation (ChIP) assays. Structural and biochemical studies reveal that T. gondii enolase functions are multifaceted, including the coordination of gene regulation in parasitic stage development. Enolase 1 provides a potential lead in the design of drugs against Toxoplasma brain cysts.
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Affiliation(s)
- Jiapeng Ruan
- Center for Structural Genomics of Infectious Diseases, Northwestern University, 320 E. Superior Street, Morton 7-601, Chicago, IL 60611, USA
| | - Thomas Mouveaux
- Center for Infection and Immunity of Lille, CNRS UMR 8204, INSERM U1019, Institut Pasteur de Lille, Université Lille Nord de France, France
| | - Samuel H. Light
- Center for Structural Genomics of Infectious Diseases, Northwestern University, 320 E. Superior Street, Morton 7-601, Chicago, IL 60611, USA
| | - George Minasov
- Center for Structural Genomics of Infectious Diseases, Northwestern University, 320 E. Superior Street, Morton 7-601, Chicago, IL 60611, USA
| | - Wayne F. Anderson
- Center for Structural Genomics of Infectious Diseases, Northwestern University, 320 E. Superior Street, Morton 7-601, Chicago, IL 60611, USA
| | - Stanislas Tomavo
- Center for Infection and Immunity of Lille, CNRS UMR 8204, INSERM U1019, Institut Pasteur de Lille, Université Lille Nord de France, France
| | - Huân M. Ngô
- Center for Structural Genomics of Infectious Diseases, Northwestern University, 320 E. Superior Street, Morton 7-601, Chicago, IL 60611, USA
- BrainMicro LLC, 21 Pendleton Street, New Haven, CT 06511, USA
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Yang N, Farrell A, Niedelman W, Melo M, Lu D, Julien L, Marth GT, Gubbels MJ, Saeij JPJ. Genetic basis for phenotypic differences between different Toxoplasma gondii type I strains. BMC Genomics 2013; 14:467. [PMID: 23837824 PMCID: PMC3710486 DOI: 10.1186/1471-2164-14-467] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 07/03/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Toxoplasma gondii has a largely clonal population in North America and Europe, with types I, II and III clonal lineages accounting for the majority of strains isolated from patients. RH, a particular type I strain, is most frequently used to characterize Toxoplasma biology. However, compared to other type I strains, RH has unique characteristics such as faster growth, increased extracellular survival rate and inability to form orally infectious cysts. Thus, to identify candidate genes that could account for these parasite phenotypic differences, we determined genetic differences and differential parasite gene expression between RH and another type I strain, GT1. Moreover, as differences in host cell modulation could affect Toxoplasma replication in the host, we determined differentially modulated host processes among the type I strains through host transcriptional profiling. RESULTS Through whole genome sequencing, we identified 1,394 single nucleotide polymorphisms (SNPs) and insertions/deletions (indels) between RH and GT1. These SNPs/indels together with parasite gene expression differences between RH and GT1 were used to identify candidate genes that could account for type I phenotypic differences. A polymorphism in dense granule protein, GRA2, determined RH and GT1 differences in the evasion of the interferon gamma response. In addition, host transcriptional profiling identified that genes regulated by NF-ĸB, such as interleukin (IL)-12p40, were differentially modulated by the different type I strains. We subsequently showed that this difference in NF-ĸB activation was due to polymorphisms in GRA15. Furthermore, we observed that RH, but not other type I strains, recruited phosphorylated IĸBα (a component of the NF-ĸB complex) to the parasitophorous vacuole membrane and this recruitment of p- IĸBα was partially dependent on GRA2. CONCLUSIONS We identified candidate parasite genes that could be responsible for phenotypic variation among the type I strains through comparative genomics and transcriptomics. We also identified differentially modulated host pathways among the type I strains, and these can serve as a guideline for future studies in examining the phenotypic differences among type I strains.
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Affiliation(s)
- Ninghan Yang
- Biology Department, Massachusetts Institute of Technology, 77 Massachusetts Ave, building 68-270, Cambridge, MA 02139, USA
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Possenti A, Fratini F, Fantozzi L, Pozio E, Dubey JP, Ponzi M, Pizzi E, Spano F. Global proteomic analysis of the oocyst/sporozoite of Toxoplasma gondii reveals commitment to a host-independent lifestyle. BMC Genomics 2013; 14:183. [PMID: 23496850 PMCID: PMC3616887 DOI: 10.1186/1471-2164-14-183] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 03/07/2013] [Indexed: 12/02/2022] Open
Abstract
Background Toxoplasmosis is caused by the apicomplexan parasite Toxoplasma gondii and can be acquired either congenitally or via the oral route. In the latter case, transmission is mediated by two distinct invasive stages, i.e., bradyzoites residing in tissue cysts or sporozoites contained in environmentally resistant oocysts shed by felids in their feces. The oocyst plays a central epidemiological role, yet this stage has been scarcely investigated at the molecular level and the knowledge of its expressed proteome is very limited. Results Using one-dimensional gel electrophoresis coupled to liquid chromatography-linked tandem mass spectrometry, we analysed total or fractionated protein extracts of partially sporulated T. gondii oocysts, producing a dataset of 1304 non reduntant proteins (~18% of the total predicted proteome), ~59% of which were classified according to the MIPS functional catalogue database. Notably, the comparison of the oocyst dataset with the extensively covered proteome of T. gondii tachyzoite, the invasive stage responsible for the clinical signs of toxoplasmosis, identified 154 putative oocyst/sporozoite-specific proteins, some of which were validated by Western blot. The analysis of this protein subset showed that, compared to tachyzoites, oocysts have a greater capability of de novo amino acid biosynthesis and are well equipped to fuel the Krebs cycle with the acetyl-CoA generated through fatty acid β-oxidation and the degradation of branched amino acids. Conclusions The study reported herein significantly expanded our knowledge of the proteome expressed by the oocyst/sporozoite of T. gondii, shedding light on a stage-specifc subset of proteins whose functional profile is consistent with the adaptation of T. gondii oocysts to the nutrient-poor and stressing extracellular environment.
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Affiliation(s)
- Alessia Possenti
- Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
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Fierce competition between Toxoplasma and Chlamydia for host cell structures in dually infected cells. EUKARYOTIC CELL 2012; 12:265-77. [PMID: 23243063 DOI: 10.1128/ec.00313-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The prokaryote Chlamydia trachomatis and the protozoan Toxoplasma gondii, two obligate intracellular pathogens of humans, have evolved a similar modus operandi to colonize their host cell and salvage nutrients from organelles. In order to gain fundamental knowledge on the pathogenicity of these microorganisms, we have established a cell culture model whereby single fibroblasts are coinfected by C. trachomatis and T. gondii. We previously reported that the two pathogens compete for the same nutrient pools in coinfected cells and that Toxoplasma holds a significant competitive advantage over Chlamydia. Here we have expanded our coinfection studies by examining the respective abilities of Chlamydia and Toxoplasma to co-opt the host cytoskeleton and recruit organelles. We demonstrate that the two pathogen-containing vacuoles migrate independently to the host perinuclear region and rearrange the host microtubular network around each vacuole. However, Toxoplasma outcompetes Chlamydia to the host microtubule-organizing center to the detriment of the bacterium, which then shifts to a stress-induced persistent state. Solely in cells preinfected with Chlamydia, the centrosomes become associated with the chlamydial inclusion, while the Toxoplasma parasitophorous vacuole displays growth defects. Both pathogens fragment the host Golgi apparatus and recruit Golgi elements to retrieve sphingolipids. This study demonstrates that the productive infection by both Chlamydia and Toxoplasma depends on the capability of each pathogen to successfully adhere to a finely tuned developmental program that aims to remodel the host cell for the pathogen's benefit. In particular, this investigation emphasizes the essentiality of host organelle interception by intravacuolar pathogens to facilitate access to nutrients.
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Nance JP, Vannella KM, Worth D, David C, Carter D, Noor S, Hubeau C, Fitz L, Lane TE, Wynn TA, Wilson EH. Chitinase dependent control of protozoan cyst burden in the brain. PLoS Pathog 2012; 8:e1002990. [PMID: 23209401 PMCID: PMC3510238 DOI: 10.1371/journal.ppat.1002990] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 09/10/2012] [Indexed: 02/07/2023] Open
Abstract
Chronic infections represent a continuous battle between the host's immune system and pathogen replication. Many protozoan parasites have evolved a cyst lifecycle stage that provides it with increased protection from environmental degradation as well as endogenous host mechanisms of attack. In the case of Toxoplasma gondii, these cysts are predominantly found in the immune protected brain making clearance of the parasite more difficult and resulting in a lifelong infection. Currently, little is known about the nature of the immune response stimulated by the presence of these cysts or how they are able to propagate. Here we establish a novel chitinase-dependent mechanism of cyst control in the infected brain. Despite a dominant Th1 immune response during Toxoplasma infection there exists a population of alternatively activated macrophages (AAMØ) in the infected CNS. These cells are capable of cyst lysis via the production of AMCase as revealed by live imaging, and this chitinase is necessary for protective immunity within the CNS. These data demonstrate chitinase activity in the brain in response to a protozoan pathogen and provide a novel mechanism to facilitate cyst clearance during chronic infections. Described here is a novel mechanism of protozoan cyst clearance in the CNS during chronic infection. These data show the presence of a population of alternatively activated macrophages in the brain that secrete the active chitinase, AMCase, in response to chitin in the cyst wall. Using both chemical and genetic inhibition in vitro, it is revealed that this enzyme is required for efficient degradation and destruction of the cyst. The necessity for AMCase is demonstrated in vivo, as the absence of the enzyme resulted in a significant increase in cyst burden and decrease in survival during chronic infection. Together, these data identify an important mechanism of parasite control and cyst clearance in the CNS. Currently, no therapies exist that lead to the total clearance of this parasite from the brain. Therefore, developing an understanding of the natural mechanisms of cyst clearance has the potential to lead to new and effective therapies for this and other chronic infections.
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Affiliation(s)
- J. Philip Nance
- Division of Biomedical Sciences, University of California, Riverside, California, United States of America
| | - Kevin M. Vannella
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Danielle Worth
- Division of Biomedical Sciences, University of California, Riverside, California, United States of America
| | - Clément David
- Division of Biomedical Sciences, University of California, Riverside, California, United States of America
| | - David Carter
- Institute for Integrative Genome Biology, University of California, Riverside, California, United States of America
| | - Shahani Noor
- Division of Biomedical Sciences, University of California, Riverside, California, United States of America
| | - Cedric Hubeau
- Department of Inflammation and Immunology, Pfizer, Cambridge, Massachusetts, United States of America
| | - Lori Fitz
- Department of Inflammation and Immunology, Pfizer, Cambridge, Massachusetts, United States of America
| | - Thomas E. Lane
- Department of Molecular Biology and Biochemistry, Institute for Immunology, University of California, Irvine, Irvine, California, United States of America
| | - Thomas A. Wynn
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Emma H. Wilson
- Division of Biomedical Sciences, University of California, Riverside, California, United States of America
- * E-mail:
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Adomako-Ankomah Y, Wier GM, Boyle JP. Beyond the genome: recent advances in Toxoplasma gondii functional genomics. Parasite Immunol 2012; 34:80-9. [PMID: 21722143 DOI: 10.1111/j.1365-3024.2011.01312.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent years have witnessed an explosion in the amount of genomic information available for Toxoplasma gondii and other closely related pathogens. These data, many of which have been made publicly available prior to publication, have facilitated a wide variety of functional genomics studies. In this review, we provide a brief overview of existing database tools for querying the Toxoplasma genome and associated genome-wide data and review recent publications that have been facilitated by these data. Topics covered include strain comparisons and quantitative trait loci mapping, gene expression analyses during the cell cycle as well as during parasite differentiation, and proteomics.
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Affiliation(s)
- Y Adomako-Ankomah
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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42
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Identification of tissue cyst wall components by transcriptome analysis of in vivo and in vitro Toxoplasma gondii bradyzoites. EUKARYOTIC CELL 2011; 10:1637-47. [PMID: 22021236 DOI: 10.1128/ec.05182-11] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Toxoplasma gondii bradyzoite is essential to establish persistent infection, yet little is known about what factors this developmental form secretes to establish the cyst or interact with its host cell. To identify candidate bradyzoite-secreted effectors, the transcriptomes of in vitro tachyzoites 2 days postinfection, in vitro bradyzoites 4 days postinfection, and in vivo bradyzoites 21 days postinfection were interrogated by microarray, and the program SignalP was used to identify signal peptides indicating secretion. One hundred two putative bradyzoite-secreted effectors were identified by this approach. Two candidates, bradyzoite pseudokinase 1 and microneme adhesive repeat domain-containing protein 4, were chosen for further investigation and confirmed to be induced and secreted by bradyzoites in vitro and in vivo. Thus, we report the first analysis of the transcriptomes of in vitro and in vivo bradyzoites and identify two new protein components of the Toxoplasma tissue cyst wall.
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Prandovszky E, Gaskell E, Martin H, Dubey JP, Webster JP, McConkey GA. The neurotropic parasite Toxoplasma gondii increases dopamine metabolism. PLoS One 2011; 6:e23866. [PMID: 21957440 PMCID: PMC3177840 DOI: 10.1371/journal.pone.0023866] [Citation(s) in RCA: 300] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 07/26/2011] [Indexed: 11/30/2022] Open
Abstract
The highly prevalent parasite Toxoplasma gondii manipulates its host's behavior. In infected rodents, the behavioral changes increase the likelihood that the parasite will be transmitted back to its definitive cat host, an essential step in completion of the parasite's life cycle. The mechanism(s) responsible for behavioral changes in the host is unknown but two lines of published evidence suggest that the parasite alters neurotransmitter signal transduction: the disruption of the parasite-induced behavioral changes with medications used to treat psychiatric disease (specifically dopamine antagonists) and identification of a tyrosine hydroxylase encoded in the parasite genome. In this study, infection of mammalian dopaminergic cells with T. gondii enhanced the levels of K+-induced release of dopamine several-fold, with a direct correlation between the number of infected cells and the quantity of dopamine released. Immunostaining brain sections of infected mice with dopamine antibody showed intense staining of encysted parasites. Based on these analyses, T. gondii orchestrates a significant increase in dopamine metabolism in neural cells. Tyrosine hydroxylase, the rate-limiting enzyme for dopamine synthesis, was also found in intracellular tissue cysts in brain tissue with antibodies specific for the parasite-encoded tyrosine hydroxylase. These observations provide a mechanism for parasite-induced behavioral changes. The observed effects on dopamine metabolism could also be relevant in interpreting reports of psychobehavioral changes in toxoplasmosis-infected humans.
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Affiliation(s)
- Emese Prandovszky
- Institute of Integrative and Comparative Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Elizabeth Gaskell
- Institute of Integrative and Comparative Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Heather Martin
- Institute of Integrative and Comparative Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - J. P. Dubey
- Animal Parasitic Diseases Laboratory, USDA, ARS, ANRI, BARC-East, Beltsville, Maryland, United States of America
| | - Joanne P. Webster
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College, London, United Kingdom
| | - Glenn A. McConkey
- Institute of Integrative and Comparative Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
- * E-mail:
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Mai K, Smith NC, Feng ZP, Katrib M, Šlapeta J, Šlapetova I, Wallach MG, Luxford C, Davies MJ, Zhang X, Norton RS, Belli SI. Peroxidase catalysed cross-linking of an intrinsically unstructured protein via dityrosine bonds in the oocyst wall of the apicomplexan parasite, Eimeria maxima. Int J Parasitol 2011; 41:1157-64. [DOI: 10.1016/j.ijpara.2011.07.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 06/30/2011] [Accepted: 07/02/2011] [Indexed: 10/18/2022]
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Comparison of molecular markers for determining the viability and infectivity of Cryptosporidium oocysts and validation of molecular methods against animal infectivity assay. Int J Infect Dis 2011; 15:e197-200. [DOI: 10.1016/j.ijid.2010.11.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 11/12/2010] [Accepted: 11/16/2010] [Indexed: 11/21/2022] Open
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Abstract
This article is an attempt to identify the most significant highlights of Toxoplasma research over the last 25 years. It has been a period of enormous progress and the top 25 most significant advances, in the view of this author, are described. These range from the bench to the bedside and represent a tremendous body of work from countless investigators. And, having laid out so much that has been discovered, it is impossible not to also reflect on the challenges that lie ahead. These, too, are briefly discussed. Finally, while every effort has been made to view the field as a whole, the molecular biology background of the author almost certainly will have skewed the relative importance attached to past and future advances. Despite this, it is hoped that the reader will agree with, or at least not disagree too strongly with, most of the choices presented here.
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Affiliation(s)
- John C Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, CA 94305-5124, USA.
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Gentry MS, Pace RM. Conservation of the glucan phosphatase laforin is linked to rates of molecular evolution and the glucan metabolism of the organism. BMC Evol Biol 2009; 9:138. [PMID: 19545434 PMCID: PMC2714694 DOI: 10.1186/1471-2148-9-138] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Accepted: 06/22/2009] [Indexed: 02/02/2023] Open
Abstract
Background Lafora disease (LD) is a fatal autosomal recessive neurodegenerative disease. A hallmark of LD is cytoplasmic accumulation of insoluble glucans, called Lafora bodies (LBs). Mutations in the gene encoding the phosphatase laforin account for ~50% of LD cases, and this gene is conserved in all vertebrates. We recently demonstrated that laforin is the founding member of a unique class of phosphatases that dephosphorylate glucans. Results Herein, we identify laforin orthologs in a protist and two invertebrate genomes, and report that laforin is absent in the vast majority of protozoan genomes and it is lacking in all other invertebrate genomes sequenced to date. We biochemically characterized recombinant proteins from the sea anemone Nematostella vectensis and the amphioxus Branchiostoma floridae to demonstrate that they are laforin orthologs. We demonstrate that the laforin gene has a unique evolutionary lineage; it is conserved in all vertebrates, a subclass of protists that metabolize insoluble glucans resembling LBs, and two invertebrates. We analyzed the intron-exon boundaries of the laforin genes in each organism and determine, based on recently published reports describing rates of molecular evolution in Branchiostoma and Nematostella, that the conservation of laforin is linked to the molecular rate of evolution and the glucan metabolism of an organism. Conclusion Our results alter the existing view of glucan phosphorylation/dephosphorylation and strongly suggest that glucan phosphorylation is a multi-Kingdom regulatory mechanism, encompassing at least some invertebrates. These results establish boundaries concerning which organisms contain laforin. Laforin is conserved in all vertebrates, it has been lost in the vast majority of lower organisms, and yet it is an ancient gene that is conserved in a subset of protists and invertebrates that have undergone slower rates of molecular evolution and/or metabolize a carbohydrate similar to LBs. Thus, the laforin gene holds a unique place in evolutionary biology and has yielded insights into glucan metabolism and the molecular etiology of Lafora disease.
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Affiliation(s)
- Matthew S Gentry
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, 741 S, Limestone, BBSRB, B177, Lexington, Kentucky 40536-0509, USA.
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Behnke MS, Radke JB, Smith AT, Sullivan WJ, White MW. The transcription of bradyzoite genes in Toxoplasma gondii is controlled by autonomous promoter elements. Mol Microbiol 2008; 68:1502-18. [PMID: 18433450 PMCID: PMC2440561 DOI: 10.1111/j.1365-2958.2008.06249.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/06/2008] [Indexed: 11/28/2022]
Abstract
Experimental evidence suggests that apicomplexan parasites possess bipartite promoters with basal and regulated cis-elements similar to other eukaryotes. Using a dual luciferase model adapted for recombinational cloning and use in Toxoplasma gondii, we show that genomic regions flanking 16 parasite genes, which encompass examples of constitutive and tachyzoite- and bradyzoite-specific genes, are able to reproduce the appropriate developmental stage expression in a transient luciferase assay. Mapping of cis-acting elements in several bradyzoite promoters led to the identification of short sequence spans that are involved in control of bradyzoite gene expression in multiple strains and under different bradyzoite induction conditions. Promoters that regulate the heat shock protein BAG1 and a novel bradyzoite-specific NTPase during bradyzoite development were fine mapped to a 6-8 bp resolution and these minimal cis-elements were capable of converting a constitutive promoter to one that is induced by bradyzoite conditions. Gel-shift experiments show that mapped cis-elements are bound by parasite protein factors with the appropriate functional sequence specificity. These studies are the first to identify the minimal sequence elements that are required and sufficient for bradyzoite gene expression and to show that bradyzoite promoters are maintained in a 'poised' chromatin state throughout the intermediate host life cycle in low passage strains. Together, these data demonstrate that conventional eukaryotic promoter mechanisms work with epigenetic processes to regulate developmental gene expression during tissue cyst formation.
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Affiliation(s)
- Michael S Behnke
- Department of Veterinary Molecular Biology, Montana State University BozemanMT 59717, USA
| | - Josh B Radke
- Department of Veterinary Molecular Biology, Montana State University BozemanMT 59717, USA
| | - Aaron T Smith
- Department Pharmacology and Toxicology, Indiana University School of MedicineIndianapolis, IN 46202, USA
| | - William J Sullivan
- Department Pharmacology and Toxicology, Indiana University School of MedicineIndianapolis, IN 46202, USA
| | - Michael W White
- Department of Veterinary Molecular Biology, Montana State University BozemanMT 59717, USA
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Guimarães EV, Acquarone M, de Carvalho L, Barbosa HS. Anionic sites on Toxoplasma gondii tissue cyst wall: Expression, uptake and characterization. Micron 2007; 38:651-8. [PMID: 17055277 DOI: 10.1016/j.micron.2006.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 09/05/2006] [Accepted: 09/07/2006] [Indexed: 10/24/2022]
Abstract
Toxoplasmosis, caused by Toxoplasma gondii, is an important parasitic disease worldwide, which causes widespread human and animal diseases. The need for new therapeutic agents along with the biology of these parasites has fueled a keen interest in the understanding of the nutrients acquisition by these parasites. Studies on the characterization of the T. gondii cyst wall as well as the contribution of the host cell to this formation have been little explored. The aim of this paper was to investigate the electric surface charge of the T. gondii tissue cysts by ultrastructural cytochemistry, through polycationic markers, employing ruthenium red (RR) and cationized ferritin (CF). Glycosaminoglycans revealed by RR were localized on the cyst wall as a homogeneous granular layer electrondense, all over its surface. The incubation of living tissue cysts with CF for 20 min at 4 degrees C followed by the increase of temperature to 37 degrees C indicated that T. gondii cyst wall is negatively charged and that occurs an incorporation of anionic sites by the cyst wall, through vesicles and tubules, and their posterior location in the cyst matrix. So, as to identify which group of molecules produces negative charge in the cyst wall, we used enzymes for cleavage on different types of molecules, demonstrating that the negative charge in the cyst wall is mainly produced by phospholipids. Our results, described in this work show, for the first time, the negativities of the cyst wall, the incorporation and the traffic of intracellular surface molecules by T. gondii cyst wall. Our model of study can give an important contribution to the knowledge of the biology and the processes involved in nutrients acquisition by bradyzoites living inside the cysts and, and also be applied as a target for the direct action of drugs against the cyst.
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Affiliation(s)
- Erick Vaz Guimarães
- Laboratório de Biologia Estrutural, Departamento de Ultra-estrutura e Biologia Celular, Instituto Oswaldo Cruz, Fiocruz, Av. Brasil 4365, 21045-900 Rio de Janeiro, RJ, Brazil
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Daher W, Oria G, Fauquenoy S, Cailliau K, Browaeys E, Tomavo S, Khalife J. A Toxoplasma gondii leucine-rich repeat protein binds phosphatase type 1 protein and negatively regulates its activity. EUKARYOTIC CELL 2007; 6:1606-17. [PMID: 17660360 PMCID: PMC2043371 DOI: 10.1128/ec.00260-07] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have characterized the Toxoplasma gondii protein phosphatase type 1 (TgPP1) and a potential regulatory binding protein belonging to the leucine-rich repeat protein family, designated TgLRR1. TgLRR1 is capable of binding to TgPP1 to inhibit its activity and to override a G(2)/M cell cycle checkpoint in Xenopus oocytes. In the parasite, TgLRR1 mRNA and protein are both highly expressed in the rapidly replicating and virulent tachyzoites, while only low levels are detected in the slowly dividing and quiescent bradyzoites. TgPP1 mRNA and protein levels are equally abundant in tachyzoites and bradyzoites. Affinity pull down and immunoprecipitation experiments reveal that the TgLRR1-TgPP1 interaction takes place in the nuclear subcompartment of tachyzoites. These results are consistent with those of localization studies using both indirect immunofluorescence with specific polyclonal antibody and transient transfection of T. gondii vector expressing TgLRR1 and TgPP1. The inability to obtain stable transgenic tachyzoites suggested that overexpression of TgLRR1 and TgPP1 may impair the parasite's growth. Together with the activation of Xenopus oocyte meiosis reinitiation, these data indicate that TgLRR1 protein could play a role in the regulation of the T. gondii cell cycle through the modulation of phosphatase activity.
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Affiliation(s)
- Wassim Daher
- Unité INSERM 547, Institut Pasteur de Lille, 1 rue du Prof. Calmette, 59019 Lille, France
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