1
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Pasquarelli RR, Quan JJ, Cheng ES, Yang V, Britton TA, Sha J, Wohlschlegel JA, Bradley PJ. Characterization and functional analysis of Toxoplasma Golgi-associated proteins identified by proximity labeling. mBio 2024:e0238024. [PMID: 39345210 DOI: 10.1128/mbio.02380-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2024] [Accepted: 08/26/2024] [Indexed: 10/01/2024] Open
Abstract
Toxoplasma gondii possesses a highly polarized secretory pathway that contains both broadly conserved eukaryotic organelles and unique apicomplexan organelles, which play essential roles in the parasite's lytic cycle. As in other eukaryotes, the T. gondii Golgi apparatus sorts and modifies proteins prior to their distribution to downstream organelles. Many of the typical trafficking factors found involved in these processes are missing from apicomplexan genomes, suggesting that these parasites have evolved unique proteins to fill these roles. Here, we identify a Golgi-localizing protein (ULP1), which is structurally similar to the eukaryotic trafficking factor p115/Uso1. We demonstrate that depletion of ULP1 leads to a dramatic reduction in parasite fitness that is the result of defects in microneme secretion, invasion, replication, and egress. Using ULP1 as bait for TurboID proximity labeling and immunoprecipitation, we identify 11 more Golgi-associated proteins and demonstrate that ULP1 interacts with the T. gondii-conserved oligomeric Golgi (COG) complex. These proteins include both conserved trafficking factors and parasite-specific proteins. Using a conditional knockdown approach, we assess the effect of each of these 11 proteins on parasite fitness. Together, this work reveals a diverse set of T. gondii Golgi-associated proteins that play distinct roles in the secretory pathway. As several of these proteins are absent outside of the Apicomplexa, they represent potential targets for the development of novel therapeutics against these parasites. IMPORTANCE Apicomplexan parasites such as Toxoplasma gondii infect a large percentage of the world's population and cause substantial human disease. These widespread pathogens use specialized secretory organelles to infect their host cells, modulate host cell functions, and cause disease. While the functions of the secretory organelles are now better understood, the Golgi apparatus of the parasite remains largely unexplored, particularly regarding parasite-specific innovations that may help direct traffic intracellularly. In this work, we characterize ULP1, a protein that is unique to parasites but shares structural similarity to the eukaryotic trafficking factor p115/Uso1. We show that ULP1 plays an important role in parasite fitness and demonstrate that it interacts with the conserved oligomeric Golgi (COG) complex. We then use ULP1 proximity labeling to identify 11 additional Golgi-associated proteins, which we functionally analyze via conditional knockdown. This work expands our knowledge of the Toxoplasma Golgi apparatus and identifies potential targets for therapeutic intervention.
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Affiliation(s)
| | - Justin J Quan
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Emily S Cheng
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Vivian Yang
- Molecular Biology Institute, University of California, Los Angeles, California, USA
| | - Timmie A Britton
- Molecular Biology Institute, University of California, Los Angeles, California, USA
| | - Jihui Sha
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, USA
| | - James A Wohlschlegel
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, USA
| | - Peter J Bradley
- Molecular Biology Institute, University of California, Los Angeles, California, USA
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, USA
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2
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Bondarenko K, Limoge F, Pedram K, Gissot M, Young JC. Enzymatically enhanced ultrastructure expansion microscopy unlocks expansion of in vitro Toxoplasma gondii cysts. mSphere 2024; 9:e0032224. [PMID: 39189782 PMCID: PMC11423595 DOI: 10.1128/msphere.00322-24] [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: 04/24/2024] [Accepted: 07/16/2024] [Indexed: 08/28/2024] Open
Abstract
Expansion microscopy (ExM) is an innovative approach to achieve super-resolution images without using super-resolution microscopes, based on the physical expansion of the sample. The advent of ExM has unlocked the detail of super-resolution images for a broader scientific circle, lowering the cost and entry skill requirements for the field. One of its branches, ultrastructure expansion microscopy (U-ExM), has become popular among research groups studying apicomplexan parasites, including the acute stage of Toxoplasma gondii infection. Here, we show that the chronic cyst-forming stage of Toxoplasma, however, resists U-ExM expansion, impeding precise protein localization. We then solve the in vitro cyst's resistance to denaturation required for successful U-ExM. As the cyst's main structural protein CST1 contains a mucin domain, we added an enzymatic digestion step using the pan-mucinase StcE prior to the expansion protocol. This allowed full expansion of the cysts in fibroblasts and primary neuronal cell culture without disrupting immunofluorescence analysis of parasite proteins. Using StcE-enhanced U-ExM, we clarified the localization of the GRA2 protein, which is important for establishing a normal cyst, observing GRA2 granules spanning across the CST1 cyst wall. The StcE-U-ExM protocol allows accurate pinpointing of proteins in the bradyzoite cyst, which will greatly facilitate investigation of the underlying biology of cyst formation and its vulnerabilities. IMPORTANCE Toxoplasma gondii is an intracellular parasite capable of establishing long-term chronic infection in nearly all warm-blooded animals. During the chronic stage, parasites encapsulate to form cysts predominantly in neurons and skeletal muscle. Current anti-Toxoplasma drugs do not eradicate chronic parasites, leaving a reservoir of infection. The cyst is critical for disease transmission and pathology, yet it is harder to study, with the function of many chronic-stage proteins still unknown. Ultrastructure expansion microscopy, a new method to overcome the light microscopy's diffraction limit by physically expanding the sample, allowed in-depth studies of acute Toxoplasma infection. We show that Toxoplasma cysts resist expansion using standard protocol, but an additional enzymatic digestion with the mucinase StcE allows full expansion. This protocol offers new avenues for examining the chronic stage, including precise spatial organization of cyst-specific proteins, linking these locations to morphological structures, and detailed investigations of components of the durable cyst wall.
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Affiliation(s)
- Kseniia Bondarenko
- Institute of Immunology and Infection Research, School of Biological Sciences, Ashworth laboratories, University of Edinburgh, Edinburgh, United Kingdom
| | - Floriane Limoge
- U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, University of Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Kayvon Pedram
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Mathieu Gissot
- U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, University of Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Joanna C. Young
- Institute of Immunology and Infection Research, School of Biological Sciences, Ashworth laboratories, University of Edinburgh, Edinburgh, United Kingdom
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3
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Wu W, Chen Q, Zou W, Chen J, Zhu D, Yang H, Ouyang L, Liu X, Peng H. Toxoplasma gondii bradyzoite-specific BAG1 is nonessential for cyst formation due to compensation by other heat-shock proteins. Parasit Vectors 2024; 17:322. [PMID: 39080770 PMCID: PMC11290284 DOI: 10.1186/s13071-024-06339-w] [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: 03/29/2024] [Accepted: 05/30/2024] [Indexed: 08/02/2024] Open
Abstract
BACKGROUND Toxoplasma gondii is an opportunistic pathogenic protozoan that infects all warm-blooded animals, including humans, and causes zoonotic toxoplasmosis. The bradyzoite antigen 1 (BAG1), known as heat-shock protein (HSP)30, is a specific antigen expressed during the early stage of T. gondii tachyzoite-bradyzoite conversion. METHODS A bag1 gene knockout strain based on the T. gondii type II ME49 was constructed and designated as ME49Δbag1. The invasion, proliferation, and cyst formation efficiency in the cell model and survival in the mouse model were compared between the ME49 and ME49Δbag1 strains after infection. Quantitative polymerase chain reaction (qPCR) was used to detect the transcriptional level of important genes, and western-blot was used to detect protein levels. RESULTS ME49Δbag1 displayed significantly inhibited cyst formation, although it was not completely blocked. During early differentiation induced by alkaline and starvation conditions in vitro, the proliferation of ME49Δbag1 was significantly accelerated relative to the ME49 strain. Meanwhile, the transcription of the HSP family and bradyzoite formation deficient 1 (bfd1) were significantly enhanced. The observed upregulation suggests a compensatory mechanism to counterbalance the impaired stress responses of T. gondii following bag1 knockout. On the other hand, the elevated transcription levels of several HSP family members, including HSP20, HSP21, HSP40, HSP60, HSP70, and HSP90, along with BFD1, implied the involvement of alternative regulatory factors in bradyzoite differentiation aside from BAG1. CONCLUSIONS The data suggested that when bag1 was absent, the stress response of T. gondii was partially compensated by increased levels of other HSPs, resulting in the formation of fewer cysts. This highlighted a complex regulatory network beyond BAG1 influencing the parasite's transformation into bradyzoites, emphasizing the vital compensatory function of HSPs in the T. gondii life cycle adaptation.
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Affiliation(s)
- Weiling Wu
- Department of Anesthesiology, The Key Laboratory of Precision Anesthesia & Perioperative Organ Protection, Baiyun Branch, Nanfang Hospital, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Diseases Research, School of Public Health, Ministry of Education, Key Laboratory of Infectious Diseases Research in South China (Southern Medical University), 1023-1063 South Shatai Rd, Guangzhou, Guangdong, People's Republic of China, 510515
| | - Qiqi Chen
- Department of Anesthesiology, The Key Laboratory of Precision Anesthesia & Perioperative Organ Protection, Baiyun Branch, Nanfang Hospital, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China
| | - Weihao Zou
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Diseases Research, School of Public Health, Ministry of Education, Key Laboratory of Infectious Diseases Research in South China (Southern Medical University), 1023-1063 South Shatai Rd, Guangzhou, Guangdong, People's Republic of China, 510515
| | - Jiating Chen
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Diseases Research, School of Public Health, Ministry of Education, Key Laboratory of Infectious Diseases Research in South China (Southern Medical University), 1023-1063 South Shatai Rd, Guangzhou, Guangdong, People's Republic of China, 510515
| | - Di Zhu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Diseases Research, School of Public Health, Ministry of Education, Key Laboratory of Infectious Diseases Research in South China (Southern Medical University), 1023-1063 South Shatai Rd, Guangzhou, Guangdong, People's Republic of China, 510515
| | - Huijing Yang
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Diseases Research, School of Public Health, Ministry of Education, Key Laboratory of Infectious Diseases Research in South China (Southern Medical University), 1023-1063 South Shatai Rd, Guangzhou, Guangdong, People's Republic of China, 510515
| | - Lishan Ouyang
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Diseases Research, School of Public Health, Ministry of Education, Key Laboratory of Infectious Diseases Research in South China (Southern Medical University), 1023-1063 South Shatai Rd, Guangzhou, Guangdong, People's Republic of China, 510515
| | - Xiaojun Liu
- Department of Anesthesiology, The Key Laboratory of Precision Anesthesia & Perioperative Organ Protection, Baiyun Branch, Nanfang Hospital, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China.
| | - Hongjuan Peng
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Diseases Research, School of Public Health, Ministry of Education, Key Laboratory of Infectious Diseases Research in South China (Southern Medical University), 1023-1063 South Shatai Rd, Guangzhou, Guangdong, People's Republic of China, 510515.
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4
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Alberione MP, González-Ruiz V, von Rohr O, Rudaz S, Soldati-Favre D, Izquierdo L, Kloehn J. N-acetylglucosamine supplementation fails to bypass the critical acetylation of glucosamine-6-phosphate required for Toxoplasma gondii replication and invasion. PLoS Pathog 2024; 20:e1011979. [PMID: 38900808 PMCID: PMC11218972 DOI: 10.1371/journal.ppat.1011979] [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: 01/17/2024] [Revised: 07/02/2024] [Accepted: 06/03/2024] [Indexed: 06/22/2024] Open
Abstract
The cell surface of Toxoplasma gondii is rich in glycoconjugates which hold diverse and vital functions in the lytic cycle of this obligate intracellular parasite. Additionally, the cyst wall of bradyzoites, that shields the persistent form responsible for chronic infection from the immune system, is heavily glycosylated. Formation of glycoconjugates relies on activated sugar nucleotides, such as uridine diphosphate N-acetylglucosamine (UDP-GlcNAc). The glucosamine-phosphate-N-acetyltransferase (GNA1) generates N-acetylglucosamine-6-phosphate critical to produce UDP-GlcNAc. Here, we demonstrate that downregulation of T. gondii GNA1 results in a severe reduction of UDP-GlcNAc and a concomitant drop in glycosylphosphatidylinositols (GPIs), leading to impairment of the parasite's ability to invade and replicate in the host cell. Surprisingly, attempts to rescue this defect through exogenous GlcNAc supplementation fail to completely restore these vital functions. In depth metabolomic analyses elucidate diverse causes underlying the failed rescue: utilization of GlcNAc is inefficient under glucose-replete conditions and fails to restore UDP-GlcNAc levels in GNA1-depleted parasites. In contrast, GlcNAc-supplementation under glucose-deplete conditions fully restores UDP-GlcNAc levels but fails to rescue the defects associated with GNA1 depletion. Our results underscore the importance of glucosamine-6-phosphate acetylation in governing T. gondii replication and invasion and highlight the potential of the evolutionary divergent GNA1 in Apicomplexa as a target for the development of much-needed new therapeutic strategies.
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Affiliation(s)
- María Pía Alberione
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-University of Barcelona, Barcelona, Spain
| | | | - Olivier von Rohr
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Serge Rudaz
- School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Luis Izquierdo
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-University of Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
| | - Joachim Kloehn
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
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5
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Nayeri T, Sarvi S, Daryani A. Effective factors in the pathogenesis of Toxoplasmagondii. Heliyon 2024; 10:e31558. [PMID: 38818168 PMCID: PMC11137575 DOI: 10.1016/j.heliyon.2024.e31558] [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: 01/03/2023] [Revised: 05/11/2024] [Accepted: 05/17/2024] [Indexed: 06/01/2024] Open
Abstract
Toxoplasma gondii (T. gondii) is a cosmopolitan protozoan parasite in humans and animals. It infects about 30 % of the human population worldwide and causes potentially fatal diseases in immunocompromised hosts and neonates. For this study, five English-language databases (ScienceDirect, ProQuest, Web of Science, PubMed, and Scopus) and the internet search engine Google Scholar were searched. This review was accomplished to draw a global perspective of what is known about the pathogenesis of T. gondii and various factors affecting it. Virulence and immune responses can influence the mechanisms of parasite pathogenesis and these factors are in turn influenced by other factors. In addition to the host's genetic background, the type of Toxoplasma strain, the routes of transmission of infection, the number of passages, and different phases of parasite life affect virulence. The identification of virulence factors of the parasite could provide promising insights into the pathogenesis of this parasite. The results of this study can be an incentive to conduct more intensive research to design and develop new anti-Toxoplasma agents (drugs and vaccines) to treat or prevent this infection. In addition, further studies are needed to better understand the key agents in the pathogenesis of T. gondii.
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Affiliation(s)
- Tooran Nayeri
- Infectious and Tropical Diseases Research Center, Dezful University of Medical Sciences, Dezful, Iran
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Shahabeddin Sarvi
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ahmad Daryani
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
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6
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Pasquarelli RR, Quan JJ, Cheng ES, Yang V, Britton TA, Sha J, Wohlschlegel JA, Bradley PJ. Characterization and functional analysis of Toxoplasma Golgi-associated proteins identified by proximity labelling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.02.578703. [PMID: 38352341 PMCID: PMC10862792 DOI: 10.1101/2024.02.02.578703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
Toxoplasma gondii possesses a highly polarized secretory pathway that contains both broadly conserved eukaryotic organelles and unique apicomplexan organelles which play essential roles in the parasite's lytic cycle. As in other eukaryotes, the T. gondii Golgi apparatus sorts and modifies proteins prior to their distribution to downstream organelles. Many of the typical trafficking factors found involved in these processes are missing from apicomplexan genomes, suggesting that these parasites have evolved unique proteins to fill these roles. Here we identify a novel Golgi-localizing protein (ULP1) which contains structural homology to the eukaryotic trafficking factor p115/Uso1. We demonstrate that depletion of ULP1 leads to a dramatic reduction in parasite fitness and replicative ability. Using ULP1 as bait for TurboID proximity labelling and immunoprecipitation, we identify eleven more novel Golgi-associated proteins and demonstrate that ULP1 interacts with the T. gondii COG complex. These proteins include both conserved trafficking factors and parasite-specific proteins. Using a conditional knockdown approach, we assess the effect of each of these eleven proteins on parasite fitness. Together, this work reveals a diverse set of novel T. gondii Golgi-associated proteins that play distinct roles in the secretory pathway. As several of these proteins are absent outside of the Apicomplexa, they represent potential targets for the development of novel therapeutics against these parasites. Importance Apicomplexan parasites such as Toxoplasma gondii infect a large percentage of the world's population and cause substantial human disease. These widespread pathogens use specialized secretory organelles to infect their host cells, modulate host cell functions, and cause disease. While the functions of the secretory organelles are now better understood, the Golgi apparatus of the parasite remains largely unexplored, particularly regarding parasite-specific innovations that may help direct traffic intracellularly. In this work, we characterize ULP1, a protein that is unique to parasites but shares structural similarity to the eukaryotic trafficking factor p115/Uso1. We show that ULP1 plays an important role in parasite replication and demonstrate that it interacts with the conserved oligomeric Golgi (COG) complex. We then use ULP1 proximity labelling to identify eleven additional Golgi-associated proteins which we functionally analyze via conditional knockdown. This work expands our knowledge of the Toxoplasma Golgi apparatus and identifies potential targets for therapeutic intervention.
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7
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Kumar P, Tomita T, Gerken TA, Ballard CJ, Lee YS, Weiss LM, Samara NL. A Toxoplasma gondii O-glycosyltransferase that modulates bradyzoite cyst wall rigidity is distinct from host homologues. Nat Commun 2024; 15:3792. [PMID: 38710711 DOI: 10.1038/s41467-024-48253-w] [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: 09/27/2023] [Accepted: 04/23/2024] [Indexed: 05/08/2024] Open
Abstract
Infection with the apicomplexan protozoan Toxoplasma gondii can be life-threatening in immunocompromised hosts. Transmission frequently occurs through the oral ingestion of T. gondii bradyzoite cysts, which transition to tachyzoites, disseminate, and then form cysts containing bradyzoites in the central nervous system, resulting in latent infection. Encapsulation of bradyzoites by a cyst wall is critical for immune evasion, survival, and transmission. O-glycosylation of the protein CST1 by the mucin-type O-glycosyltransferase T. gondii (Txg) GalNAc-T3 influences cyst wall rigidity and stability. Here, we report X-ray crystal structures of TxgGalNAc-T3, revealing multiple features that are strictly conserved among its apicomplexan homologues. This includes a unique 2nd metal that is coupled to substrate binding and enzymatic activity in vitro and cyst wall O-glycosylation in T. gondii. The study illustrates the divergence of pathogenic protozoan GalNAc-Ts from their host homologues and lays the groundwork for studying apicomplexan GalNAc-Ts as therapeutic targets in disease.
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Affiliation(s)
- Pranav Kumar
- Structural Biochemistry Unit, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD, 20892, USA
| | - Tadakimi Tomita
- Department of Pathology, Albert Einstein College of Medicine, Bronx, 1300 Morris Park Avenue, New York, 10461, USA
| | - Thomas A Gerken
- Departments of Biochemistry and Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Collin J Ballard
- Departments of Biochemistry and Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Yong Sok Lee
- Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, 20892, USA
| | - Louis M Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, 1300 Morris Park Avenue, New York, 10461, USA
- Department of Medicine (Infectious Disease), Albert Einstein College of Medicine, Bronx 1300 Morris Park Avenue, New York, 10461, USA
| | - Nadine L Samara
- Structural Biochemistry Unit, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD, 20892, USA.
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8
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Marsilia C, Batra M, Pokrovskaya ID, Wang C, Chaput D, Naumova DA, Lupashin VV, Suvorova ES. Essential role of the conserved oligomeric Golgi complex in Toxoplasma gondii. mBio 2023; 14:e0251323. [PMID: 37966241 PMCID: PMC10746232 DOI: 10.1128/mbio.02513-23] [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: 09/18/2023] [Accepted: 10/05/2023] [Indexed: 11/16/2023] Open
Abstract
IMPORTANCE The Golgi is an essential eukaryotic organelle and a major place for protein sorting and glycosylation. Among apicomplexan parasites, Toxoplasma gondii retains the most developed Golgi structure and produces many glycosylated factors necessary for parasite survival. Despite its importance, Golgi function received little attention in the past. In the current study, we identified and characterized the conserved oligomeric Golgi complex and its novel partners critical for protein transport in T. gondii tachyzoites. Our results suggest that T. gondii broadened the role of the conserved elements and reinvented the missing components of the trafficking machinery to accommodate the specific needs of the opportunistic parasite T. gondii.
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Affiliation(s)
- Clem Marsilia
- Division of Infectious Diseases, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Mrinalini Batra
- Division of Infectious Diseases, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Irina D. Pokrovskaya
- Department of Physiology and Cell Biology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Changqi Wang
- College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Dale Chaput
- Proteomics Core, College of Arts and Sciences, University of South Florida, Tampa, Florida, USA
| | - Daria A. Naumova
- Division of Infectious Diseases, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Vladimir V. Lupashin
- Department of Physiology and Cell Biology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Elena S. Suvorova
- Division of Infectious Diseases, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
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9
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De Benedetto I, Biagini F, Urbano G, Mongini TE, Cassetta I, Scaglione L, Curtoni A, Calleri G, Calcagno A, De Rosa FG, Corcione S. A case of histological diagnosis of Toxoplasma gondii myositis in a person living with HIV. LE INFEZIONI IN MEDICINA 2023; 31:407-410. [PMID: 37701394 PMCID: PMC10495058 DOI: 10.53854/liim-3103-16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 08/15/2023] [Indexed: 09/14/2023]
Abstract
We report the case of a 58-year-old male with a recent diagnosis of HIV infection admitted for progressive muscular weakness and psychomotor impairment. Cerebrospinal examination documented a mild hyperproteinorrachia, with normal cells count and reduced glycorrhachia. Brain gadolinium-enhanced MRI showed bilateral T2 and FLAIR hyperintensities in the nucleo-capsular region and irregular contrast-enhancement of the globi pallidi and the right putamen. The histologic analysis of a quadriceps biopsy showed several foci of inflammatory infiltrates with concomitant muscular fiber atrophy and degeneration. Scattered intracytoplasmic inclusions were observed in muscle fibers, representing the main pathological feature. A positive PCR for Toxoplasma gondii and a Toxoplasma gondii specific monoclonal antibody immunohistochemical staining confirmed the diagnosis.
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Affiliation(s)
- Ilaria De Benedetto
- Department of Medical Sciences, Infectious Diseases, University of Turin, Turin, Italy
| | - Francesco Biagini
- Internal Medicine Unit, University Hospital Città della Salute e della Scienza di Torino, Turin, Italy
| | - Guido Urbano
- Neuromuscular Center, University Hospital Città della Salute e della Scienza di Torino, Department of Neurosciences RLM, University of Turin, Turin, Italy
| | - Tiziana Enrica Mongini
- Neuromuscular Center, University Hospital Città della Salute e della Scienza di Torino, Department of Neurosciences RLM, University of Turin, Turin, Italy
| | - Ilaria Cassetta
- Internal Medicine Unit, University Hospital Città della Salute e della Scienza di Torino, Turin, Italy
| | - Luca Scaglione
- Internal Medicine Unit, University Hospital Città della Salute e della Scienza di Torino, Turin, Italy
| | - Antonio Curtoni
- Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Turin, Italy
| | - Guido Calleri
- Department of Infectious Diseases, Travel Medicine Unit, Amedeo di Savoia Hospital, Torino, Italy
| | - Andrea Calcagno
- Department of Medical Sciences, Infectious Diseases, University of Turin, Turin, Italy
| | - Francesco Giuseppe De Rosa
- Department of Medical Sciences, Infectious Diseases, University of Turin, Turin, Italy
- Infectious Diseases Unit, Cardinal Massaia Hospital, Asti, Italy
| | - Silvia Corcione
- Department of Medical Sciences, Infectious Diseases, University of Turin, Turin, Italy
- Tufts University School of Medicine, Boston, MA, USA
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10
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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: 21] [Impact Index Per Article: 10.5] [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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Pan M, Ge CC, Fan YM, Jin QW, Shen B, Huang SY. The determinants regulating Toxoplasma gondii bradyzoite development. Front Microbiol 2022; 13:1027073. [PMID: 36439853 PMCID: PMC9691885 DOI: 10.3389/fmicb.2022.1027073] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/24/2022] [Indexed: 11/04/2023] Open
Abstract
Toxoplasma gondii is an obligate intracellular zoonotic pathogen capable of infecting almost all cells of warm-blooded vertebrates. In intermediate hosts, this parasite reproduces asexually in two forms, the tachyzoite form during acute infection that proliferates rapidly and the bradyzoite form during chronic infection that grows slowly. Depending on the growth condition, the two forms can interconvert. The conversion of tachyzoites to bradyzoites is critical for T. gondii transmission, and the reactivation of persistent bradyzoites in intermediate hosts may lead to symptomatic toxoplasmosis. However, the mechanisms that control bradyzoite differentiation have not been well studied. Here, we review recent advances in the study of bradyzoite biology and stage conversion, aiming to highlight the determinants associated with bradyzoite development and provide insights to design better strategies for controlling toxoplasmosis.
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Affiliation(s)
- Ming Pan
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Ceng-Ceng Ge
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Yi-Min Fan
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Qi-Wang Jin
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Bang Shen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Si-Yang Huang
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China
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12
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Rezende-Gondim MM, da Silva AV, Dubey JP, Schares GRM, Gondim LFP. Immunomagnetic separation of Toxoplasma gondii and Hammondia spp. tissue cysts generated in cell culture. Front Vet Sci 2022; 9:1033380. [PMID: 36311681 PMCID: PMC9606798 DOI: 10.3389/fvets.2022.1033380] [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: 08/31/2022] [Accepted: 09/22/2022] [Indexed: 11/04/2022] Open
Abstract
Toxoplasma gondii is commonly transmitted among animals and humans by ingestion of infected animal tissues or by consumption of food and water contaminated with environmentally-resistant oocysts excreted by cats. Tissue cysts and oocysts have different walls, whose structures and compositions are poorly known. Herein, we describe an immunomagnetic separation (IMS) method that was successfully used for purification of T. gondii tissue cysts generated in cell culture. We used an IgG monoclonal antibody (mAb) that reacts against antigens in tissue cyst walls. Many in vitro produced cysts were obtained by this IMS; >2,000 T. gondii cysts were isolated from a single culture flask of 25 cm2. Tissue cysts from two Hammondia spp., H. hammondi, and H. heydorni, produced in cell culture were also separated using this method. As a reference, purification of tissue cysts by Percoll gradients was used. Percoll was able to separate T. gondii tissue cysts produced in mice but was not suitable for purifying T. gondii tissue cysts produced in vitro. The IMS described here should favor proteomic studies involving tissue cysts of T. gondii.
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Affiliation(s)
- Mariana M. Rezende-Gondim
- Departamento de Anatomia, Patologia e Clínicas, Escola de Medicina Veterinária e Zootecnia, Universidade Federal da Bahia, Salvador, Bahia, Brazil
| | - Aristeu V. da Silva
- Departamento de Biologia, Universidade Estadual de Feira de Santana, Feira de Santana, Bahia, Brazil
| | - Jitender P. Dubey
- United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Beltsville, MD, United States
| | - Gereon R. M. Schares
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, National Reference Centre for Toxoplasmosis, Greifswald-Insel Riems, Germany
| | - Luís F. P. Gondim
- Departamento de Anatomia, Patologia e Clínicas, Escola de Medicina Veterinária e Zootecnia, Universidade Federal da Bahia, Salvador, Bahia, Brazil,*Correspondence: Luís F. P. Gondim
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13
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Tian X, Wang M, Xie T, Wan G, Sun H, Mei X, Zhang Z, Li X, Wang S. A recombinant protein vaccine encoding Toxoplasma gondii Cyst wall 2 (dense granule protein 47) provides partial protection against acute and chronic T. gondii infection in BALB/c mice. Acta Trop 2022; 232:106514. [PMID: 35580637 DOI: 10.1016/j.actatropica.2022.106514] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 05/09/2022] [Accepted: 05/10/2022] [Indexed: 11/26/2022]
Abstract
Toxoplasma gondii poses a major threat to economies and public health, and there are still no available vaccines for human against T. gondii infection. T. gondii cyst wall 2 (TgCST2, also known as dense granule protein-47) is a critical molecule in the establishment of chronic infection, making it a potential vaccine candidate. In this research, the recombinant TgCST2 (rTgCST2) was employed to evaluate the protective efficacy of TgCST2 antigen using BALB/c mice model against T. gondii infections via active immunization trials. First, the strong immunogenicity of TgCST2 was indicated by immunoblotting and immunofluorescence, which mean that TgCST2 might elicit robust immune responses in the organism. Then, after triply subcutaneous immunization with rTgCST2/ISA 201 emulsion, high levels of Toxoplasma-specific IgG, IgG1, IgG2a and cytokines (Interferon γ and interleukin 10) further suggested that TgCST2 was a promising immunogenic antigen. More importantly, this antigen could prolong survival in RH strain infected mice and resulted in the lower brain cysts size and number of PRU strain infected mice. These preliminary results demonstrated the immunoprophylactic effects of TgCST2 antigen and will inform new studies in developing subunit recombinant vaccines against T. gondii.
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14
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Fu Y, Brown KM, Jones NG, Moreno SNJ, Sibley LD. Toxoplasma bradyzoites exhibit physiological plasticity of calcium and energy stores controlling motility and egress. eLife 2021; 10:e73011. [PMID: 34860156 PMCID: PMC8683080 DOI: 10.7554/elife.73011] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 12/03/2021] [Indexed: 01/01/2023] Open
Abstract
Toxoplasma gondii has evolved different developmental stages for disseminating during acute infection (i.e., tachyzoites) and establishing chronic infection (i.e., bradyzoites). Calcium ion (Ca2+) signaling tightly regulates the lytic cycle of tachyzoites by controlling microneme secretion and motility to drive egress and cell invasion. However, the roles of Ca2+ signaling pathways in bradyzoites remain largely unexplored. Here, we show that Ca2+ responses are highly restricted in bradyzoites and that they fail to egress in response to agonists. Development of dual-reporter parasites revealed dampened Ca2+ responses and minimal microneme secretion by bradyzoites induced in vitro or harvested from infected mice and tested ex vivo. Ratiometric Ca2+ imaging demonstrated lower Ca2+ basal levels, reduced magnitude, and slower Ca2+ kinetics in bradyzoites compared with tachyzoites stimulated with agonists. Diminished responses in bradyzoites were associated with downregulation of Ca2+-ATPases involved in intracellular Ca2+ storage in the endoplasmic reticulum (ER) and acidocalcisomes. Once liberated from cysts by trypsin digestion, bradyzoites incubated in glucose plus Ca2+ rapidly restored their intracellular Ca2+ and ATP stores, leading to enhanced gliding. Collectively, our findings indicate that intracellular bradyzoites exhibit dampened Ca2+ signaling and lower energy levels that restrict egress, and yet upon release they rapidly respond to changes in the environment to regain motility.
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Affiliation(s)
- Yong Fu
- Department of Molecular Microbiology, Washington University in St. Louis, School of MedicineSt LouisUnited States
| | - Kevin M Brown
- Department of Molecular Microbiology, Washington University in St. Louis, School of MedicineSt LouisUnited States
| | - Nathaniel G Jones
- Department of Molecular Microbiology, Washington University in St. Louis, School of MedicineSt LouisUnited States
| | - Silvia NJ Moreno
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of GeorgiaAthensUnited States
| | - L David Sibley
- Department of Molecular Microbiology, Washington University in St. Louis, School of MedicineSt LouisUnited States
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15
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Multimodal regulation of encystation in Giardia duodenalis revealed by deep proteomics. Int J Parasitol 2021; 51:809-824. [PMID: 34331939 DOI: 10.1016/j.ijpara.2021.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/24/2020] [Accepted: 01/07/2021] [Indexed: 12/21/2022]
Abstract
Cyst formation in the parasitic protist Giardia duodenalis is critical to its transmission. Existing proteomic data quantifies only 17% of coding genes transcribed during encystation and does not cover the complete process from trophozoite to mature cyst. Using high-resolution mass spectrometry, we have quantified proteomic changes across encystation and compared this with published transcriptomic data. We reproducibly identified 3863 (64.5% of Giardia proteins) and quantified 3382 proteins (56.5% of Giardia proteins) over standard trophozoite growth (TY), during low-bile encystation priming (LB), 16 h into encystation (EC), and at cyst maturation (C). This work provides the first known expanded observation of encystation at the proteomic level and triples the coverage of previous encystation proteomes. One-third (1169 proteins) of the quantified proteome is differentially expressed in the mature cyst relative to the trophozoite, including proteasomal machinery, metabolic pathways, and secretory proteins. Changes in lipid metabolism indicated a shift in lipid species dependency during encystation. Consistent with this, we identified the first, putative lipid transporters in this species, representing the steroidogenic acute regulatory protein-related lipid transfer (StARkin), oxysterol binding protein related protein (ORP/Osh) and glycosphingolipid transfer protein (GLTP) families, and follow their differential expression over cyst formation. Lastly, we undertook correlation analyses of the transcriptome and proteome of trophozoites and cysts, and found evidence of post-transcriptional regulation of key protein classes (RNA binding proteins) and stage-specific genes (encystation markers) implicating translation-repression in encystation. We provide the most extensive proteomic analysis of encystation in Giardia to date and the first known exploration across its complete duration. This work identifies encystation as highly coordinated, involving major changes in proteostasis, metabolism and membrane dynamics, and indicates a potential role for post-transcriptional regulation, mediated through RNA-binding proteins. Together our work provides a valuable resource for Giardia research and the development of transmission-blocking anti-giardials.
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16
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Hamie M, Tawil N, El Hajj R, Najm R, Moodad S, Hleihel R, Karam M, El Sayyed S, Besteiro S, El-Sabban M, Dubremetz JF, Lebrun M, El Hajj H. P18 (SRS35/TgSAG4) Plays a Role in the Invasion and Virulence of Toxoplasma gondii. Front Immunol 2021; 12:643292. [PMID: 34262559 PMCID: PMC8273438 DOI: 10.3389/fimmu.2021.643292] [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: 12/17/2020] [Accepted: 06/10/2021] [Indexed: 11/13/2022] Open
Abstract
Toxoplasmosis is a prevalent parasitic disease caused by Toxoplasma gondii (T. gondii). Under the control of the host immune system, T. gondii persists as latent bradyzoite cysts. Immunosuppression leads to their reactivation, a potentially life-threatening condition. Interferon-gamma (IFN-γ) controls the different stages of toxoplasmosis. Here, we addressed the role of the parasite surface antigen P18, belonging to the Surface-Antigen 1 (SAG-1) Related Sequence (SRS) family, in a cyst-forming strain. Deletion of P18 gene (KO P18) impaired the invasion of parasites in macrophages and IFN-γ-mediated activation of macrophages further reduced the invasion capacity of this KO, as compared to WT strain. Mice infected by KO P18, showed a marked decrease in virulence during acute toxoplasmosis. This was consequent to less parasitemia, accompanied by a substantial recruitment of dendritic cells, macrophages and natural killer cells (NK). Furthermore, KO P18 resulted in a higher number of bradyzoite cysts, and a stronger inflammatory response. A prolonged survival of mice was observed upon immunosuppression of KO P18 infected BALB/c mice or upon oral infection of Severe Combined Immunodeficiency (SCID) mice, with intact macrophages and natural killer (NK) cells. In stark contrast, oral infection of NSG (NOD/Shi-scid/IL-2Rγnull) mice, defective in macrophages and NK cells, with KO P18, was as lethal as that of the control strain showing that the conversion from bradyzoites to tachyzoites is intact and, suggesting a role of P18 in the response to host IFN-γ. Collectively, these data demonstrate a role for P18 surface antigen in the invasion of macrophages and in the virulence of the parasite, during acute and chronic toxoplasmosis.
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Affiliation(s)
- Maguy Hamie
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Nadim Tawil
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Rana El Hajj
- Department of Biological Sciences, Beirut Arab University, Beirut, Lebanon
| | - Rania Najm
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Sara Moodad
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Rita Hleihel
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Martin Karam
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Sana El Sayyed
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | | | - Marwan El-Sabban
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | | | - Maryse Lebrun
- LPHI UMR5235, Univ Montpellier, CNRS, Montpellier, France
| | - Hiba El Hajj
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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17
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Tomita T, Mukhopadhyay D, Han B, Yakubu R, Tu V, Mayoral J, Sugi T, Ma Y, Saeij JPJ, Weiss LM. Toxoplasma gondii Matrix Antigen 1 Is a Secreted Immunomodulatory Effector. mBio 2021; 12:mBio.00603-21. [PMID: 34006649 PMCID: PMC8262993 DOI: 10.1128/mbio.00603-21] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Our studies on novel cyst wall proteins serendipitously led us to the discovery that cyst wall and vacuolar matrix protein MAG1, first identified a quarter of a century ago, functions as a secreted immunomodulatory effector. MAG1 is a dense granular protein that is found in the parasitophorous vacuolar matrix in tachyzoite vacuoles and the cyst wall and matrix in bradyzoite vacuoles. In the current study, we demonstrated that MAG1 is secreted beyond the parasitophorous vacuole into the host cytosol in both tachyzoites and bradyzoites. Secretion of MAG1 gradually decreases as the parasitophorous vacuole matures, but prominent MAG1 puncta are present inside host cells even at 4 and 6 days following infection. During acute murine infection, Δmag1 parasites displayed significantly reduced virulence and dissemination. In the chronic stage of infection, Δmag1 parasites generated almost no brain cysts. To identify the mechanism behind the attenuated pathology seen with Δmag1 parasites, various immune responses were screened in vitro using bone marrow-derived macrophages (BMDM). Infection of BMDM with Δmag1 parasites induced a significant increase in interleukin 1β (IL-1β) secretion, which is a hallmark of inflammasome activation. Heterologous complementation of MAG1 in BMDM cells prevented this Δmag1 parasite-induced IL-1β release, indicating that secreted MAG1 in host cytosol dampens inflammasome activation. Furthermore, knocking out GRA15 (an inducer of IL-1β release) in Δmag1 parasites completely inhibited all IL-1β release by host cells following infection. These data suggest that MAG1 has a role as an immunomodulatory molecule and that by suppressing inflammasome activation, it would favor survival of the parasite and the establishment of latent infection.IMPORTANCEToxoplasma gondii is an Apicomplexan that infects a third of humans, causing encephalitis in AIDS patients and intellectual disabilities in congenitally infected patients. We determined that one of the cyst matrix proteins, MAG1, which had been thought to be an innate structural protein, can be secreted into the host cell and suppress the host immune reaction. This particular immune reaction is initiated by another parasite-secreted protein, GRA15. The intricate balance of inflammasome activation by GRA15 and suppression by MAG1 protects mice from acute death while enabling parasites to disseminate and establish chronic cysts. Our finding contributes to our understanding of how parasites persist in the host and how T. gondii modulates the host immune system.
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Affiliation(s)
- Tadakimi Tomita
- Department of Pathology, Albert Einstein College of Medicine, New York, New York, USA
| | - Debanjan Mukhopadhyay
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Bing Han
- Department of Pathology, Albert Einstein College of Medicine, New York, New York, USA
| | - Rama Yakubu
- Department of Pathology, Albert Einstein College of Medicine, New York, New York, USA
| | - Vincent Tu
- Department of Pathology, Albert Einstein College of Medicine, New York, New York, USA
| | - Joshua Mayoral
- Department of Pathology, Albert Einstein College of Medicine, New York, New York, USA
| | - Tatsuki Sugi
- Department of Pathology, Albert Einstein College of Medicine, New York, New York, USA
| | - Yanfen Ma
- Department of Pathology, Albert Einstein College of Medicine, New York, New York, USA
| | - Jeroen P J Saeij
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Louis M Weiss
- Department of Pathology, Albert Einstein College of Medicine, New York, New York, USA
- Department of Medicine, Albert Einstein College of Medicine, New York, New York, USA
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18
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Guevara RB, Fox BA, Bzik DJ. A Family of Toxoplasma gondii Genes Related to GRA12 Regulate Cyst Burdens and Cyst Reactivation. mSphere 2021; 6:e00182-21. [PMID: 33883265 PMCID: PMC8546695 DOI: 10.1128/msphere.00182-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 03/26/2021] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii causes a chronic infection that renders the immunocompromised human host susceptible to toxoplasmic encephalitis triggered by cyst reactivation in the central nervous system. The dense granule protein GRA12 is a major parasite virulence factor required for parasite survival during acute infection. Here, we characterized the role of four GRA12-related genes in acute and chronic stages of infection. While GRA12A, GRA12B, and GRA12D were highly expressed in asexual stage tachyzoites and bradyzoites, expression of GRA12C appeared to be restricted to the sexual stages. In contrast to deletion of GRA12 (Δgra12), no major defects in acute virulence were observed in Δgra12A, Δgra12B, or Δgra12D parasites, though Δgra12B parasites exhibited an increased tachyzoite replication rate. Bradyzoites secreted GRA12A, GRA12B, and GRA12D and incorporated these molecules into the developing cyst wall, as well as the cyst matrix in distinct patterns. Similar to GRA12, GRA12A, GRA12B, and GRA12D colocalized with the dense granules in extracellular tachyzoites, with GRA2 and the intravacuolar network in the tachyzoite stage parasitophorous vacuole and with GRA2 in the cyst matrix and cyst wall. Chronic stage cyst burdens were decreased in mice infected with Δgra12A parasites and were increased in mice infected with Δgra12B parasites. However, Δgra12B cysts were not efficiently maintained in vivo Δgra12A, Δgra12B, and Δgra12D in vitro cysts displayed a reduced reactivation efficiency, and reactivation of Δgra12A cysts was delayed. Collectively, our results suggest that a family of genes related to GRA12 play significant roles in the formation, maintenance, and reactivation of chronic stage cysts.IMPORTANCE If host immunity weakens, Toxoplasma gondii cysts recrudesce in the central nervous system and cause a severe toxoplasmic encephalitis. Current therapies target acute stage infection but do not eliminate chronic cysts. Parasite molecules that mediate the development and persistence of chronic infection are poorly characterized. Dense granule (GRA) proteins such as GRA12 are key virulence factors during acute infection. Here, we investigated four GRA12-related genes. GRA12-related genes were not major virulence factors during acute infection. Instead, GRA12-related proteins localized at the cyst wall and cyst matrix and played significant roles in cyst development, persistence, and reactivation during chronic infection. Similar to GRA12, the GRA12-related proteins selectively associated with the intravacuolar network of membranes inside the vacuole. Collectively, our results support the hypothesis that GRA12 proteins associated with the intravacuolar membrane system support parasite virulence during acute infection and cyst development, persistence, and reactivation during chronic infection.
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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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19
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Dard C, Swale C, Brenier-Pinchart MP, Farhat DC, Bellini V, Robert MG, Cannella D, Pelloux H, Tardieux I, Hakimi MA. A brain cyst load-associated antigen is a Toxoplasma gondii biomarker for serodetection of persistent parasites and chronic infection. BMC Biol 2021; 19:25. [PMID: 33557824 PMCID: PMC7871634 DOI: 10.1186/s12915-021-00959-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 01/12/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Biomarker discovery remains a major challenge for predictive medicine, in particular, in the context of chronic diseases. This is true for the widespread protozoan Toxoplasma gondii which establishes long-lasting parasitism in metazoans, humans included. This microbe successively unfolds distinct genetic programs that direct the transition from high to low replicative potential inside host cells. As a slow-replicating cell, the T. gondii bradyzoite developmental stage persists enclosed in a cyst compartment within tissues including the nervous system, being held by a sustained immune equilibrium which accounts for the prolonged clinically silent phase of parasitism. Serological surveys indicate that nearly one third of the human population has been exposed to T. gondii and possibly host bradyzoites. Because any disruption of the immune balance drives the reverse transition from bradyzoite to fast replicating tachyzoite and uncontrolled growth of the latter, these people are at risk for life-threatening disease. While serological tests for discriminating recent from past infection are available, there is yet no immunogenic biomarker used in the serological test to allow ascertaining the presence of persistent bradyzoites. RESULTS Capitalizing on genetically engineered parasites induced to produce mature bradyzoites in vitro, we have identified the BCLA/MAG2 protein being restricted to the bradyzoite and the cyst envelope. Using laboratory mice as relevant T. gondii host models, we demonstrated that BCLA/MAG2 drives the generation of antibodies that recognize bradyzoite and the enveloping cyst structure. We have designed an ELISA assay based on a bacterially produced BCLA recombinant polypeptide, which was validated using a large collection of sera from mice of different genetic backgrounds and infected with bcla+ or bcla-null cystogenic and non-cystogenic T. gondii strains. To refine the design of the ELISA assay, we applied high-resolution BCLA epitope mapping and identified a specific combination of peptides and accordingly set up a selective and sensitive ELISA assay which allowed the detection of anti-BCLA/MAG2 antibodies in the sera of human patients with various forms of toxoplasmosis. CONCLUSIONS We brought proof of principle that anti-BCLA/MAG2 antibodies serve as specific and sensitive serological markers in the perspective of a combinatorial strategy for detection of persistent T. gondii parasitism.
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Affiliation(s)
- Céline Dard
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
- Laboratory of Parasitology and Mycology, Grenoble Alpes University Hospital, CS10217, 38043, Grenoble, France
| | - Christopher Swale
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Marie-Pierre Brenier-Pinchart
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
- Laboratory of Parasitology and Mycology, Grenoble Alpes University Hospital, CS10217, 38043, Grenoble, France
| | - Dayana C Farhat
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Valeria Bellini
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Marie Gladys Robert
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
- Laboratory of Parasitology and Mycology, Grenoble Alpes University Hospital, CS10217, 38043, Grenoble, France
| | - Dominique Cannella
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Hervé Pelloux
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
- Laboratory of Parasitology and Mycology, Grenoble Alpes University Hospital, CS10217, 38043, Grenoble, France
| | - Isabelle Tardieux
- Team Membrane and Cell Dynamics of Host Parasite Interactions, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Mohamed-Ali Hakimi
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France.
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Bandini G, Agop-Nersesian C, van der Wel H, Mandalasi M, Kim HW, West CM, Samuelson J. The nucleocytosolic O-fucosyltransferase SPINDLY affects protein expression and virulence in Toxoplasma gondii. J Biol Chem 2021; 296:100039. [PMID: 33158988 PMCID: PMC7949088 DOI: 10.1074/jbc.ra120.015883] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/23/2020] [Accepted: 11/06/2020] [Indexed: 12/12/2022] Open
Abstract
Once considered unusual, nucleocytoplasmic glycosylation is now recognized as a conserved feature of eukaryotes. While in animals, O-GlcNAc transferase (OGT) modifies thousands of intracellular proteins, the human pathogen Toxoplasma gondii transfers a different sugar, fucose, to proteins involved in transcription, mRNA processing, and signaling. Knockout experiments showed that TgSPY, an ortholog of plant SPINDLY and paralog of host OGT, is required for nuclear O-fucosylation. Here we verify that TgSPY is the nucleocytoplasmic O-fucosyltransferase (OFT) by 1) complementation with TgSPY-MYC3, 2) its functional dependence on amino acids critical for OGT activity, and 3) its ability to O-fucosylate itself and a model substrate and to specifically hydrolyze GDP-Fuc. While many of the endogenous proteins modified by O-Fuc are important for tachyzoite fitness, O-fucosylation by TgSPY is not essential. Growth of Δspy tachyzoites in fibroblasts is modestly affected, despite marked reductions in the levels of ectopically expressed proteins normally modified with O-fucose. Intact TgSPY-MYC3 localizes to the nucleus and cytoplasm, whereas catalytic mutants often displayed reduced abundance. Δspy tachyzoites of a luciferase-expressing type II strain exhibited infection kinetics in mice similar to wild-type but increased persistence in the chronic brain phase, potentially due to an imbalance of regulatory protein levels. The modest changes in parasite fitness in vitro and in mice, despite profound effects on reporter protein accumulation, and the characteristic punctate localization of O-fucosylated proteins suggest that TgSPY controls the levels of proteins to be held in reserve for response to novel stresses.
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Affiliation(s)
- Giulia Bandini
- Department of Molecular and Cell Biology, Boston University Henry Goldman School of Dental Medicine, Boston, Massachusetts, USA.
| | - Carolina Agop-Nersesian
- Department of Molecular and Cell Biology, Boston University Henry Goldman School of Dental Medicine, Boston, Massachusetts, USA
| | - Hanke van der Wel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - 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
| | - 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
| | - John Samuelson
- Department of Molecular and Cell Biology, Boston University Henry Goldman School of Dental Medicine, Boston, Massachusetts, USA
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21
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Daniel EJP, las Rivas M, Lira-Navarrete E, García-García A, Hurtado-Guerrero R, Clausen H, Gerken TA. Ser and Thr acceptor preferences of the GalNAc-Ts vary among isoenzymes to modulate mucin-type O-glycosylation. Glycobiology 2020; 30:910-922. [PMID: 32304323 PMCID: PMC7581654 DOI: 10.1093/glycob/cwaa036] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/30/2020] [Accepted: 04/12/2020] [Indexed: 12/12/2022] Open
Abstract
A family of polypeptide GalNAc-transferases (GalNAc-Ts) initiates mucin-type O-glycosylation, transferring GalNAc onto hydroxyl groups of Ser and Thr residues of target substrates. The 20 GalNAc-T isoenzymes in humans are classified into nine subfamilies according to sequence similarity. GalNAc-Ts select their sites of glycosylation based on weak and overlapping peptide sequence motifs, as well prior substrate O-GalNAc glycosylation at sites both remote (long-range) and neighboring (short-range) the acceptor. Together, these preferences vary among GalNAc-Ts imparting each isoenzyme with its own unique specificity. Studies on the first identified GalNAc-Ts showed Thr acceptors were preferred over Ser acceptors; however studies comparing Thr vs. Ser glycosylation across the GalNAc-T family are lacking. Using a series of identical random peptide substrates, with single Thr or Ser acceptor sites, we determined the rate differences (Thr/Ser rate ratio) between Thr and Ser substrate glycosylation for 12 isoenzymes (representing 7 GalNAc-T subfamilies). These Thr/Ser rate ratios varied across subfamilies, ranging from ~2 to ~18 (for GalNAc-T4/GalNAc-T12 and GalNAc-T3/GalNAc-T6, respectively), while nearly identical Thr/Ser rate ratios were observed for isoenzymes within subfamilies. Furthermore, the Thr/Ser rate ratios did not appreciably vary over a series of fixed sequence substrates of different relative activities, suggesting the ratio is a constant for each isoenzyme against single acceptor substrates. Finally, based on GalNAc-T structures, the different Thr/Ser rate ratios likely reflect differences in the strengths of the Thr acceptor methyl group binding to the active site pocket. With this work, another activity that further differentiates substrate specificity among the GalNAc-Ts has been identified.
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Affiliation(s)
| | - Matilde las Rivas
- BIFI and Laboratorio de Microscopías Avanzada (LMA), University of Zaragoza, Mariano Esquillor s/n, Campus Rio Ebro, Edificio I+D, Zaragoza, 50018, Spain
| | - Erandi Lira-Navarrete
- BIFI and Laboratorio de Microscopías Avanzada (LMA), University of Zaragoza, Mariano Esquillor s/n, Campus Rio Ebro, Edificio I+D, Zaragoza, 50018, Spain
| | - Ana García-García
- BIFI and Laboratorio de Microscopías Avanzada (LMA), University of Zaragoza, Mariano Esquillor s/n, Campus Rio Ebro, Edificio I+D, Zaragoza, 50018, Spain
| | - Ramon Hurtado-Guerrero
- BIFI and Laboratorio de Microscopías Avanzada (LMA), University of Zaragoza, Mariano Esquillor s/n, Campus Rio Ebro, Edificio I+D, Zaragoza, 50018, Spain
- Department of Cellular and Molecular Medicine, Faculty of Health Sciences, Copenhagen Center for Glycomics (CCG), University of Copenhagen, Copenhagen N DK-2200, Denmark
- Department of Dentistry, Faculty of Health Sciences, Copenhagen Center for Glycomics (CCG), University of Copenhagen, Copenhagen N DK-2200, Denmark
- Fundación ARAID, Zaragoza, 50018, Spain
| | - Henrik Clausen
- Department of Cellular and Molecular Medicine, Faculty of Health Sciences, Copenhagen Center for Glycomics (CCG), University of Copenhagen, Copenhagen N DK-2200, Denmark
- Department of Dentistry, Faculty of Health Sciences, Copenhagen Center for Glycomics (CCG), University of Copenhagen, Copenhagen N DK-2200, Denmark
| | - Thomas A Gerken
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106, USA
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106, USA
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106, USA
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22
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Ortiz-Guerrero G, Gonzalez-Reyes RE, de-la-Torre A, Medina-Rincón G, Nava-Mesa MO. Pathophysiological Mechanisms of Cognitive Impairment and Neurodegeneration by Toxoplasma gondii Infection. Brain Sci 2020; 10:brainsci10060369. [PMID: 32545619 PMCID: PMC7349234 DOI: 10.3390/brainsci10060369] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/09/2020] [Accepted: 06/11/2020] [Indexed: 12/12/2022] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite considered one of the most successful pathogens in the world, owing to its ability to produce long-lasting infections and to persist in the central nervous system (CNS) in most warm-blooded animals, including humans. This parasite has a preference to invade neurons and affect the functioning of glial cells. This could lead to neurological and behavioral changes associated with cognitive impairment. Although several studies in humans and animal models have reported controversial results about the relationship between toxoplasmosis and the onset of dementia as a causal factor, two recent meta-analyses have shown a relative association with Alzheimer’s disease (AD). AD is characterized by amyloid-β (Aβ) peptide accumulation, neurofibrillary tangles, and neuroinflammation. Different authors have found that toxoplasmosis may affect Aβ production in brain areas linked with memory functioning, and can induce a central immune response and neurotransmitter imbalance, which in turn, affect the nervous system microenvironment. In contrast, other studies have revealed a reduction of Aβ plaques and hyperphosphorylated tau protein formation in animal models, which might cause some protective effects. The aim of this article is to summarize and review the newest data in regard to different pathophysiological mechanisms of cerebral toxoplasmosis and their relationship with the development of AD and cognitive impairment. All these associations should be investigated further through clinical and experimental studies.
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Affiliation(s)
- Gloria Ortiz-Guerrero
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA;
| | - Rodrigo E. Gonzalez-Reyes
- GI en Neurociencias-NeURos, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá 111221, Colombia; (R.E.G.-R.); (A.d.-l.-T.); (G.M.-R.)
| | - Alejandra de-la-Torre
- GI en Neurociencias-NeURos, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá 111221, Colombia; (R.E.G.-R.); (A.d.-l.-T.); (G.M.-R.)
| | - German Medina-Rincón
- GI en Neurociencias-NeURos, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá 111221, Colombia; (R.E.G.-R.); (A.d.-l.-T.); (G.M.-R.)
| | - Mauricio O. Nava-Mesa
- GI en Neurociencias-NeURos, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá 111221, Colombia; (R.E.G.-R.); (A.d.-l.-T.); (G.M.-R.)
- Correspondence: ; Tel.: +57-1-2970200 (ext. 3354); Fax: +571-3440351
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23
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Nadipuram SM, Thind AC, Rayatpisheh S, Wohlschlegel JA, Bradley PJ. Proximity biotinylation reveals novel secreted dense granule proteins of Toxoplasma gondii bradyzoites. PLoS One 2020; 15:e0232552. [PMID: 32374791 PMCID: PMC7202600 DOI: 10.1371/journal.pone.0232552] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 04/16/2020] [Indexed: 02/06/2023] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite which is capable of establishing life-long chronic infection in any mammalian host. During the intracellular life cycle, the parasite secretes an array of proteins into the parasitophorous vacuole (PV) where it resides. Specialized organelles called the dense granules secrete GRA proteins that are known to participate in nutrient acquisition, immune evasion, and host cell-cycle manipulation. Although many GRAs have been discovered which are expressed during the acute infection mediated by tachyzoites, little is known about those that participate in the chronic infection mediated by the bradyzoite form of the parasite. In this study, we sought to uncover novel bradyzoite-upregulated GRA proteins using proximity biotinylation, which we previously used to examine the secreted proteome of the tachyzoites. Using a fusion of the bradyzoite upregulated protein MAG1 to BirA* as bait and a strain with improved switch efficiency, we identified a number of novel GRA proteins which are expressed in bradyzoites. After using the CRISPR/Cas9 system to characterize these proteins by gene knockout, we focused on one of these GRAs (GRA55) and found it was important for the establishment or maintenance of cysts in the mouse brain. These findings highlight new components of the GRA proteome of the tissue-cyst life stage of T. gondii and identify potential targets that are important for maintenance of parasite persistence in vivo.
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Affiliation(s)
- Santhosh Mukund Nadipuram
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, United States of America
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Cedar-Sinai Medical Center, Los Angeles, California, United States of America
| | - Amara Cervantes Thind
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, United States of America
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
| | - Shima Rayatpisheh
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, United States of America
| | - James Akira Wohlschlegel
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, United States of America
| | - Peter John Bradley
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, United States of America
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
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24
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The Bradyzoite: A Key Developmental Stage for the Persistence and Pathogenesis of Toxoplasmosis. Pathogens 2020; 9:pathogens9030234. [PMID: 32245165 PMCID: PMC7157559 DOI: 10.3390/pathogens9030234] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 12/19/2022] Open
Abstract
Toxoplasma gondii is a ubiquitous parasitic protist found in a wide variety of hosts, including a large proportion of the human population. Beyond an acute phase which is generally self-limited in immunocompetent individuals, the ability of the parasite to persist as a dormant stage, called bradyzoite, is an important aspect of toxoplasmosis. Not only is this stage not eliminated by current treatments, but it can also reactivate in immunocompromised hosts, leading to a potentially fatal outcome. Yet, despite its critical role in the pathology, the bradyzoite stage is relatively understudied. One main explanation is that it is a considerably challenging model, which essentially has to be derived from in vivo sources. However, recent progress on genetic manipulation and in vitro differentiation models now offers interesting perspectives for tackling key biological questions related to this particularly important developmental stage.
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25
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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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26
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Tu V, Mayoral J, Yakubu RR, Tomita T, Sugi T, Han B, Williams T, Ma Y, Weiss LM. MAG2, a Toxoplasma gondii Bradyzoite Stage-Specific Cyst Matrix Protein. mSphere 2020; 5:e00100-20. [PMID: 32075884 PMCID: PMC7031614 DOI: 10.1128/msphere.00100-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 02/03/2020] [Indexed: 12/21/2022] Open
Abstract
Toxoplasma gondii causes a chronic infection that affects a significant portion of the world's population, and this latent infection is the source of reactivation of toxoplasmosis. An attribute of the slowly growing bradyzoite stage of the parasite is the formation of a cyst within infected cells, allowing the parasite to escape the host's immune response. In this study, a new bradyzoite cyst matrix antigen (MAG) was identified through a hybridoma library screen. This cyst matrix antigen, matrix antigen 2 (MAG2), contains 14 tandem repeats consisting of acidic, basic, and proline residues. Immunoblotting revealed that MAG2 migrates at a level higher than its predicted molecular weight, and computational analysis showed that the structure of MAG2 is highly disordered. Cell fractionation studies indicated that MAG2 was associated with both insoluble and soluble cyst matrix material, suggesting that it interacts with the intracyst network (ICN). Examination of the kinetics of MAG2 within the cyst matrix using fluorescence recovery after photobleaching (FRAP) demonstrated that MAG2 does not readily diffuse within the cyst matrix. Kinetic studies of MAG1 demonstrated that this protein has different diffusion kinetics in tachyzoite and bradyzoite vacuoles and that its mobility is not altered in the absence of MAG2. In addition, deletion of MAG2 does not influence growth, cystogenesis, or cyst morphology.IMPORTANCE This report expands on the list of characterized Toxoplasma gondii cyst matrix proteins. Using fluorescence recovery after photobleaching (FRAP), we have shown that matrix proteins within the cyst matrix are not mainly in a mobile state, providing further evidence of how proteins behave within the cyst matrix. Understanding the proteins expressed during the bradyzoite stage of the parasite reveals how the parasite functions during chronic infection.
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Affiliation(s)
- Vincent Tu
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Joshua Mayoral
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Rama R Yakubu
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Tadakimi Tomita
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Tatsuki Sugi
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Bing Han
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Tere Williams
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Yanfen Ma
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Louis M Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
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27
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Tu V, Tomita T, Sugi T, Mayoral J, Han B, Yakubu RR, Williams T, Horta A, Ma Y, Weiss LM. The Toxoplasma gondii Cyst Wall Interactome. mBio 2020; 11:e02699-19. [PMID: 32019789 PMCID: PMC7002340 DOI: 10.1128/mbio.02699-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/23/2019] [Indexed: 12/17/2022] Open
Abstract
A characteristic of the latent cyst stage of Toxoplasma gondii is a thick cyst wall that forms underneath the membrane of the bradyzoite vacuole. Previously, our laboratory group published a proteomic analysis of purified in vitro cyst wall fragments that identified an inventory of cyst wall components. To further refine our understanding of the composition of the cyst wall, several cyst wall proteins were tagged with a promiscuous biotin ligase (BirA*), and their interacting partners were screened by streptavidin affinity purification. Within the cyst wall pulldowns, previously described cyst wall proteins, dense granule proteins, and uncharacterized hypothetical proteins were identified. Several of the newly identified hypothetical proteins were validated to be novel components of the cyst wall and tagged with BirA* to expand the model of the cyst wall interactome. Community detection of the cyst wall interactome model revealed three distinct clusters: a dense granule, a cyst matrix, and a cyst wall cluster. Characterization of several of the identified cyst wall proteins using genetic strategies revealed that MCP3 affects in vivo cyst sizes. This study provides a model of the potential protein interactions within the cyst wall and the groundwork to understand cyst wall formation.IMPORTANCE A model of the cyst wall interactome was constructed using proteins identified through BioID. The proteins within this cyst wall interactome model encompass several proteins identified in a prior characterization of the cyst wall proteome. This model provides a more comprehensive understanding of the composition of the cyst wall and may lead to insights on how the cyst wall is formed.
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Affiliation(s)
- Vincent Tu
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Tadakimi Tomita
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Tatsuki Sugi
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Joshua Mayoral
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Bing Han
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Rama R Yakubu
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Tere Williams
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Aline Horta
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Yanfen Ma
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Louis M Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
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28
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Waldman BS, Schwarz D, Wadsworth MH, Saeij JP, Shalek AK, Lourido S. Identification of a Master Regulator of Differentiation in Toxoplasma. Cell 2020; 180:359-372.e16. [PMID: 31955846 PMCID: PMC6978799 DOI: 10.1016/j.cell.2019.12.013] [Citation(s) in RCA: 137] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 10/28/2019] [Accepted: 12/10/2019] [Indexed: 01/06/2023]
Abstract
Toxoplasma gondii chronically infects a quarter of the world's population, and its recrudescence can cause life-threatening disease in immunocompromised individuals and recurrent ocular lesions in the immunocompetent. Acute-stage tachyzoites differentiate into chronic-stage bradyzoites, which form intracellular cysts resistant to immune clearance and existing therapies. The molecular basis of this differentiation is unknown, despite being efficiently triggered by stresses in culture. Through Cas9-mediated screening and single-cell profiling, we identify a Myb-like transcription factor (BFD1) necessary for differentiation in cell culture and in mice. BFD1 accumulates during stress and its synthetic expression is sufficient to drive differentiation. Consistent with its function as a transcription factor, BFD1 binds the promoters of many stage-specific genes and represents a counterpoint to the ApiAP2 factors that dominate our current view of parasite gene regulation. BFD1 provides a genetic switch to study and control Toxoplasma differentiation and will inform prevention and treatment of chronic infections.
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Affiliation(s)
- Benjamin S Waldman
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Dominic Schwarz
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Marc H Wadsworth
- Institute for Medical Engineering & Science, Department of Chemistry, and Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02319, USA
| | - Jeroen P Saeij
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Alex K Shalek
- Institute for Medical Engineering & Science, Department of Chemistry, and Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02319, USA
| | - Sebastian Lourido
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
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29
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Guevara RB, Fox BA, Bzik DJ. Toxoplasma gondii Parasitophorous Vacuole Membrane-Associated Dense Granule Proteins Regulate Maturation of the Cyst Wall. mSphere 2020; 5:e00851-19. [PMID: 31941814 PMCID: PMC6968655 DOI: 10.1128/msphere.00851-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 12/19/2019] [Indexed: 11/20/2022] Open
Abstract
After differentiation is triggered, the tachyzoite-stage Toxoplasma gondii parasitophorous vacuole membrane (PVM) has been hypothesized to transition into the cyst membrane that surrounds the cyst wall and encloses bradyzoites. Here, we tracked the localization of two PVM dense granule (GRA) proteins (GRA5 and GRA7) after in vitro differentiation of the tachyzoite stage parasitophorous vacuole into the mature cyst. GRA5 and GRA7 were visible at the cyst periphery at 6 h and at all later times after differentiation, suggesting that the PVM remained intact as it transitioned into the cyst membrane. By day 3 postdifferentiation, GRA5 and GRA7 were visible in a continuous pattern at the cyst periphery. In mature 7- and 10-day-old cysts permeabilized with a saponin pulse, GRA5 and GRA7 were localized to the cyst membrane and the cyst wall regions. Cysts at different stages of cyst development exhibited differential susceptibility to saponin permeabilization, and, correspondingly, saponin selectively removed GRA5 from the cyst membrane and cyst wall region in 10-day-old cysts. GRA5 and GRA7 were localized at the cyst membrane and cyst wall region at all times after differentiation of the parasitophorous vacuole, which supports a previous model proposing that the PVM develops into the cyst membrane. In addition, evaluation of Δgra3, Δgra5, Δgra7, Δgra8, and Δgra14 mutants revealed that PVM-localized GRAs were crucial to support the normal rate of accumulation of cyst wall proteins at the cyst periphery.IMPORTANCEToxoplasma gondii establishes chronic infection in humans by forming thick-walled cysts that persist in the brain. Once host immunity wanes, cysts reactivate to cause severe, and often lethal, toxoplasmic encephalitis. There is no available therapy to eliminate cysts or to prevent their reactivation. Furthermore, how the cyst membrane and cyst wall structures develop is poorly understood. Here, we visualized and tracked the localization of Toxoplasma parasitophorous vacuole membrane (PVM) dense granules (GRA) proteins during cyst development in vitro. PVM-localized GRA5 and GRA7 were found at the cyst membrane and cyst wall region throughout cyst development, suggesting that the PVM remains intact and develops into the cyst membrane. In addition, our results show that genetic deletion of PVM GRAs reduced the rate of accumulation of cyst wall cargo at the cyst periphery and suggest that PVM-localized GRAs mediate the development and maturation of the cyst wall and cyst membrane.
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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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Abstract
Toxoplasma gondii, a member of the Apicomplexa, is known for its ability to infect an impressive range of host species. It is a common human infection that causes significant morbidity in congenitally infected children and immunocompromised patients. This parasite can be transmitted by bradyzoites, a slowly replicating life stage found within intracellular tissue cysts, and oocysts, the sexual life cycle stage that develops in domestic cats and other Felidae. T. gondii bradyzoites retain the capacity to revert back to the quickly replicating tachyzoite life stage, and when the host is immune compromised unrestricted replication can lead to significant tissue destruction. Bradyzoites are refractory to currently available Toxoplasma treatments. Improving our understanding of bradyzoite biology is critical for the development of therapeutic strategies to eliminate latent infection. This chapter describes a commonly used protocol for the differentiation of T. gondii tachyzoites into bradyzoites using human foreskin fibroblast cultures and a CO2-limited alkaline cell media, which results in a high proportion of differentiated bradyzoites for further study. Also described are methods for purifying tissue cysts from chronically infected mouse brain using isopycnic centrifugation and a recently developed approach for measuring bradyzoite viability.
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Bandini G, Albuquerque-Wendt A, Hegermann J, Samuelson J, Routier FH. Protein O- and C-Glycosylation pathways in Toxoplasma gondii and Plasmodium falciparum. Parasitology 2019; 146:1755-1766. [PMID: 30773146 PMCID: PMC6939170 DOI: 10.1017/s0031182019000040] [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: 10/23/2018] [Revised: 12/22/2018] [Accepted: 01/10/2019] [Indexed: 12/28/2022]
Abstract
Apicomplexan parasites are amongst the most prevalent and morbidity-causing pathogens worldwide. They are responsible for severe diseases in humans and livestock and are thus of great public health and economic importance. Until the sequencing of apicomplexan genomes at the beginning of this century, the occurrence of N- and O-glycoproteins in these parasites was much debated. The synthesis of rudimentary and divergent N-glycans due to lineage-specific gene loss is now well established and has been recently reviewed. Here, we will focus on recent studies that clarified classical O-glycosylation pathways and described new nucleocytosolic glycosylations in Toxoplasma gondii, the causative agents of toxoplasmosis. We will also review the glycosylation of proteins containing thrombospondin type 1 repeats by O-fucosylation and C-mannosylation, newly discovered in Toxoplasma and the malaria parasite Plasmodium falciparum. The functional significance of these post-translational modifications has only started to emerge, but the evidence points towards roles for these protein glycosylation pathways in tissue cyst wall rigidity and persistence in the host, oxygen sensing, and stability of proteins involved in host invasion.
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Affiliation(s)
- Giulia Bandini
- Department of Molecular and Cell Biology, Boston University, Goldman School of Dental Medicine, 72 East Concord Street, Boston, MA 02118, USA
| | - Andreia Albuquerque-Wendt
- Department of Clinical Biochemistry OE4340, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Jan Hegermann
- Hannover Medical School, Electron Microscopy Facility OE8840, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - John Samuelson
- Department of Molecular and Cell Biology, Boston University, Goldman School of Dental Medicine, 72 East Concord Street, Boston, MA 02118, USA
| | - Françoise H. Routier
- Department of Clinical Biochemistry OE4340, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
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Guevara RB, Fox BA, Falla A, Bzik DJ. Toxoplasma gondii Intravacuolar-Network-Associated Dense Granule Proteins Regulate Maturation of the Cyst Matrix and Cyst Wall. mSphere 2019; 4:e00487-19. [PMID: 31619500 PMCID: PMC6796980 DOI: 10.1128/msphere.00487-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 09/30/2019] [Indexed: 11/21/2022] Open
Abstract
Little is known regarding how the chronic Toxoplasma gondii cyst develops. Here, we investigated intravacuolar-network-associated dense granule (GRA) proteins GRA1, GRA2, GRA4, GRA6, GRA9, and GRA12 during cyst development in vitro after differentiation of the tachyzoite-stage parasitophorous vacuole. By day 1 postdifferentiation, GRA1, GRA4, GRA6, GRA9, and GRA12 colocalized with Dolichos biflorus agglutinin stain at the cyst periphery. In contrast, GRA2 remained in the cyst matrix. By day 2 postdifferentiation, coinciding with localization of GRA2 to the cyst periphery, GRA1, GRA4, GRA6, and GRA9 established a continuous matrix pattern in the cyst. In contrast, GRA2 and GRA12 were colocalized in prominent cyst matrix puncta throughout cyst development. While GRA2, GRA6, and GRA12 localized in outer and inner layers of the cyst wall, GRA1, GRA4, and GRA9 localized predominantly in the inner layers of the cyst wall. GRA2 and GRA12 were colocalized in the cyst wall by day 7 postdifferentiation. However, by day 10 postdifferentiation, GRA12 was relocalized from the cyst wall to puncta in the cyst matrix. Differentiation of Δgra2 parasites revealed a defect in the ability to establish a normal cyst matrix. In addition, the deletion of any intravacuolar-network-associated GRA protein, except GRA1, reduced the rate of accumulation of cyst wall proteins at the cyst periphery relative to the cyst interior. Our findings reveal dynamic patterns of GRA protein localization during cyst development and suggest that intravacuolar-network-associated GRA proteins regulate the formation and maturation of the cyst matrix and cyst wall structures.IMPORTANCEToxoplasma gondii establishes chronic infection in humans by forming thick-walled cysts that persist in the brain. If host immunity wanes, cysts reactivate to cause severe, and often lethal, toxoplasmic encephalitis. There is no available therapy to eliminate cysts or to prevent their reactivation. Moreover, how the vital and characteristic cyst matrix and cyst wall structures develop is poorly understood. Here, we visualized and tracked the localization of Toxoplasma intravacuolar-network-associated dense granule (GRA) proteins during cyst development in vitro Intravacuolar-network GRAs were present within the cyst matrix and at the cyst wall in developing cysts, and genetic deletion of intravacuolar-network-associated GRAs reduced the rate of accumulation of cyst wall material at the cyst periphery. Our results show that intravacuolar-network-associated GRAs, particularly GRA2 and GRA12, play dynamic and essential roles in the development and maturation of the cyst matrix and the cyst wall structures.
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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
| | - Alejandra Falla
- 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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Turupcu A, Poliak P, Margreitter C, Oostenbrink C, Staudacher E. UDP-N-acetyl-α-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase from the snail Biomphalaria glabrata - structural reflections. Glycoconj J 2019; 37:15-25. [PMID: 31396754 PMCID: PMC6994419 DOI: 10.1007/s10719-019-09886-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 07/02/2019] [Accepted: 07/18/2019] [Indexed: 11/26/2022]
Abstract
UDP-GalNAc:polypeptide GalNAc transferase (ppGalNAcT; EC 2.4.1.41) is the initiating enzyme for mucin-type O-glycosylation in animals. Members of this highly conserved glycosyltransferase family catalyse a single glycosidic linkage. They transfer an N-acetylgalactosamine (GalNAc) residue from an activated donor (UDP-GalNAc) to a serine or threonine of an acceptor polypeptide chain. A ppGalNAcT from the freshwater snail Biomphalaria glabrata is the only characterised member of this enzyme family from mollusc origin. In this work, we interpret previously published experimental characterization of this enzyme in the context of in silico models of the enzyme and its acceptor substrates. A homology model of the mollusc ppGalNAcT is created and various substrate peptides are modelled into the active site. We hypothesize about possible molecular interpretations of the available experimental data and offer potential explanations for observed substrate and cofactor specificity. Here, we review and synthesise the current knowledge of Bge-ppGalNAcT, supported by a molecular interpretation of the available data.
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Affiliation(s)
- Aysegül Turupcu
- Institute for Molecular Modeling and Simulation, Department of Material Sciences and Process Engineering, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190, Vienna, Austria
| | - Peter Poliak
- Institute for Molecular Modeling and Simulation, Department of Material Sciences and Process Engineering, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190, Vienna, Austria
- Department of Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovakia
| | - Christian Margreitter
- Randall Centre for Cell & Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, SE1 9RT, UK
| | - Chris Oostenbrink
- Institute for Molecular Modeling and Simulation, Department of Material Sciences and Process Engineering, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190, Vienna, Austria
| | - Erika Staudacher
- Department of Chemistry, Glycobiology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190, Vienna, Austria.
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Fox BA, Guevara RB, Rommereim LM, Falla A, Bellini V, Pètre G, Rak C, Cantillana V, Dubremetz JF, Cesbron-Delauw MF, Taylor GA, Mercier C, Bzik DJ. Toxoplasma gondii Parasitophorous Vacuole Membrane-Associated Dense Granule Proteins Orchestrate Chronic Infection and GRA12 Underpins Resistance to Host Gamma Interferon. mBio 2019; 10:e00589-19. [PMID: 31266861 PMCID: PMC6606796 DOI: 10.1128/mbio.00589-19] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 06/04/2019] [Indexed: 12/29/2022] Open
Abstract
Toxoplasma gondii evades host immunity to establish a chronic infection. Here, we assessed the role of parasitophorous vacuole (PV) membrane (PVM)- and intravacuolar network (IVN) membrane-localized dense granule (GRA) proteins in the development of acute and chronic Toxoplasma infection. Deletion of PVM-associated GRA3, GRA7, GRA8, and GRA14 or IVN membrane-associated GRA2, GRA9, and GRA12 in the low-virulence type II Prugniaud (Pru) strain induced severe defects in the development of chronic-stage cysts in vivo without affecting the parasite growth rate or the ability to differentiate into cysts in vitro Acute virulence of the PruΔgra2, PruΔgra3, and PruΔgra4 mutants was reduced but not abolished. In contrast, the PruΔgra12 mutant was avirulent in mice and PruΔgra12 parasites failed to establish a chronic infection. High-virulence type I strain RHΔgra12 parasites also exhibited a major defect in acute virulence. In gamma interferon (IFN-γ)-activated macrophages, type I RHΔgra12 and type II PruΔgra12 parasites resisted the coating of the PVM with host immunity-related GTPases as effectively as the parental type I RHΔku80 and type II PruΔku80 strains, respectively. Despite this resistance, Δgra12 PVs ultimately succumbed to IFN-γ-activated host cell innate immunity. Our findings uncover a key role for GRA12 in mediating resistance to host IFN-γ and reveal that many other IVN membrane-associated GRA proteins, as well as PVM-localized GRA proteins, play important roles in establishing chronic infection.IMPORTANCEToxoplasma gondii cysts reactivate during immune deficiency and cause fatal encephalitis. Parasite molecules that coordinate the development of acute and chronic infection are poorly characterized. Here, we show that many intravacuolar network membrane and parasitophorous vacuole membrane-associated dense granule (GRA) proteins orchestrate the development of chronic cysts in vivo A subset of these GRA proteins also modulate acute virulence, and one protein that associates with the intravacuolar network membranes, namely GRA12, was identified as a major virulence factor required for parasite resistance to host gamma interferon (IFN-γ). Our results revealed that many parasitophorous vacuole membrane and intravacuolar network membrane-associated GRA proteins are essential for successful chronic infection.
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Affiliation(s)
- Barbara A Fox
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Rebekah B Guevara
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Leah M Rommereim
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Alejandra Falla
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Valeria Bellini
- Laboratoire Techniques de l'Ingénierie Médicale et de la Complexité-Informatique, Mathématiques, Applications, Grenoble (TIMC-IMAG), Université Grenoble Alpes, Grenoble, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5525, Grenoble, France
| | - Graciane Pètre
- Laboratoire Techniques de l'Ingénierie Médicale et de la Complexité-Informatique, Mathématiques, Applications, Grenoble (TIMC-IMAG), Université Grenoble Alpes, Grenoble, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5525, Grenoble, France
| | - Camille Rak
- Laboratoire Techniques de l'Ingénierie Médicale et de la Complexité-Informatique, Mathématiques, Applications, Grenoble (TIMC-IMAG), Université Grenoble Alpes, Grenoble, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5525, Grenoble, France
| | - Viviana Cantillana
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
- Department of Immunology, Duke University Medical Center, Durham, North Carolina, USA
- Division of Geriatrics, Duke University Medical Center, Durham, North Carolina, USA
- Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, North Carolina, USA
| | - Jean-François Dubremetz
- Université Montpellier 2, Montpellier, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5235, Montpellier, France
| | - Marie-France Cesbron-Delauw
- Laboratoire Techniques de l'Ingénierie Médicale et de la Complexité-Informatique, Mathématiques, Applications, Grenoble (TIMC-IMAG), Université Grenoble Alpes, Grenoble, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5525, Grenoble, France
| | - Gregory A Taylor
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
- Department of Immunology, Duke University Medical Center, Durham, North Carolina, USA
- Division of Geriatrics, Duke University Medical Center, Durham, North Carolina, USA
- Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, North Carolina, USA
- Geriatric Research, Education and Clinical Center, VA Medical Center, Durham, North Carolina, USA
| | - Corinne Mercier
- Laboratoire Techniques de l'Ingénierie Médicale et de la Complexité-Informatique, Mathématiques, Applications, Grenoble (TIMC-IMAG), Université Grenoble Alpes, Grenoble, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5525, Grenoble, France
| | - David J Bzik
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
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Zhang S, Bai L, Chen Q, Ren Y, Zhang K, Wu Q, Huang H, Li W, Zhang Y, Zhang J, Liu Y. Identification of the O-GalNAcylation site(s) on FOXA1 catalyzed by ppGalNAc-T2 enzyme in vitro. Biochem Biophys Res Commun 2019; 514:157-165. [PMID: 31029427 DOI: 10.1016/j.bbrc.2019.04.146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 04/19/2019] [Indexed: 01/05/2023]
Abstract
FOXA1 functions as a pioneer factor of transcriptional regulation that binds to specific sites in the chromatin and recruits other transcription factors, promoting the initiation of gene transcription and mediating the regulation of downstream target gene expression. FOXA1 was reported to facilitate or reprogram ERα binding, thus playing a key function in breast cancer progression. Our previous results indicated that the O-linked N-acetylgalactosamine (O-GalNAc) modification of FOXA1 plays a potentially significant role in the ERα transcription network. However, further investigations are needed to identify the specific mechanism of modification and the specific glycosylation sites on FOXA1. In this study, we first suggested that FOXA1 could be O-GalNAcylated by ppGalNAc-T2 in vitro. By dividing and expressing recombinant FOXA1 as three segments, two O-GalNAcylation sites were found on FOXA1, both located at the C-terminal of the protein. Then, synthesized peptides, including the predicted O-GalNAc sites in the C-terminus of FOXA1, were used in a vitro reaction, and peptides mutated at the predicted O-GalNAc sites were employed as controls. Through an ESI-MS assay, S354 and S355 were identified as probable O-GalNAcylation sites on FOXA1. Additionally, we performed ESI-ETD-MS/MS analysis of the full-length O-GalNAcylated FOXA1 protein and identified S355 as the O-GalNAc modification site on FOXA1, consistent with the peptide reaction. In conclusion, our results demonstrated that FOXA1 can be O-GalNAcylated by ppGalNAc-T2 at S355 in vitro. These results will provide new insights for studying the role of O-GalNAcylation in the development of breast cancer.
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Affiliation(s)
- Siqi Zhang
- School of Life Science & Medicine, Dalian University of Technology, Panjin, China
| | - Lijuan Bai
- School of Life Science & Medicine, Dalian University of Technology, Panjin, China
| | - Qiushi Chen
- BGI-Shenzhen, Yantian District, Shenzhen, China
| | - Yan Ren
- BGI-Shenzhen, Yantian District, Shenzhen, China
| | - Keren Zhang
- BGI-Shenzhen, Yantian District, Shenzhen, China
| | - Qiong Wu
- School of Life Science & Medicine, Dalian University of Technology, Panjin, China
| | - Huang Huang
- School of Life Science & Medicine, Dalian University of Technology, Panjin, China
| | - Wenli Li
- School of Life Science & Medicine, Dalian University of Technology, Panjin, China
| | - Yan Zhang
- Shanghai Center for Systems Biomedicine (SCSB), Shanghai Jiao Tong University, Shanghai, China.
| | - Jianing Zhang
- School of Life Science & Medicine, Dalian University of Technology, Panjin, China.
| | - Yubo Liu
- School of Life Science & Medicine, Dalian University of Technology, Panjin, China.
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Tu V, Mayoral J, Sugi T, Tomita T, Han B, Ma YF, Weiss LM. Enrichment and Proteomic Characterization of the Cyst Wall from In Vitro Toxoplasma gondii Cysts. mBio 2019; 10:e00469-19. [PMID: 31040239 PMCID: PMC6495374 DOI: 10.1128/mbio.00469-19] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 03/25/2019] [Indexed: 01/08/2023] Open
Abstract
The tissue cyst of Toxoplasma gondii, found in latent infection, serves a critical role in both transmission and reactivation of this organism. Within infected cells, slowly replicating parasites (bradyzoites) are surrounded by a cyst matrix, cyst wall, and cyst membrane. The cyst wall is clearly delineated by ultrastructural analysis; however, the composition and function of this layer in host-parasite interactions are not fully understood. In order to understand the composition of the cyst wall, a proteomic analysis of purified cyst wall fragments, that were enriched with Percoll gradients and subsequently immunoprecipitated with CST1 antibody, was performed. Known cyst wall proteins, such as CST1, BPK1, MCP4, MAG1, GRA2, GRA3, and GRA5, were identified in this preparation by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In addition, dense granule proteins (GRAs) not previously shown to associate with the cyst wall, as well as uncharacterized hypothetical proteins, were identified in this cyst wall preparation. Several of these hypothetical cyst wall (CST) proteins were epitope tagged, and immunofluorescence assays confirmed their localization as novel cyst matrix and cyst wall proteins. Expression of two of these newly identified cyst wall proteins was eliminated by gene knockout (CST2-KO and CST3-KO). CST2-KO parasites were highly attenuated in virulence and did not establish detectable cyst burdens. This targeted proteomic approach allowed the identification of new components of the cyst wall that probably have roles in the parasite/host interface.IMPORTANCEToxoplasma gondii is a highly prevalent parasite worldwide that presents life-threatening risks to immunocompromised and pregnant individuals. Whereas the life stage responsible for acute infection can be treated, the life stage responsible for chronic infection is refractory to currently available therapeutics. Little is known about the protein composition of the cyst wall, an amorphous structure formed by parasites that is suspected to facilitate persistence within muscle and nervous tissue during chronic (latent) infection. By implementing a refined approach to selectively purify cyst wall fragments, we identified several known and novel cyst wall proteins from our sample preparations. We confirmed the localizations of several proteins from this data set and identified one that is involved in parasite virulence. These data will propel further studies on cyst wall structure and function, leading to therapeutic strategies that can eliminate the chronic infection stage.
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Affiliation(s)
- Vincent Tu
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Joshua Mayoral
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Tatsuki Sugi
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
- IVD Development Unit, Medical & Biological Laboratories Co. Ltd., Ina, Nagano, Japan
| | - Tadakimi Tomita
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Bing Han
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Yan Fen Ma
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Louis M Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
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Zhu W, Li J, Pappoe F, Shen J, Yu L. Strategies Developed by Toxoplasma gondii to Survive in the Host. Front Microbiol 2019; 10:899. [PMID: 31080445 PMCID: PMC6497798 DOI: 10.3389/fmicb.2019.00899] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 04/09/2019] [Indexed: 12/21/2022] Open
Abstract
One of the most successful intracellular parasites, Toxoplasma gondii has developed several strategies to avoid destruction by the host. These include approaches such as rapid and efficient cell invasion to avoid phagocytic engulfment, negative regulation of the canonical CD40-CD40L-mediated autophagy pathway, impairment of the noncanonical IFN-γ-dependent autophagy pathway, and modulation of host cell survival and death to obtain lifelong parasite survival. Different virulent strains have even evolved different ways to cope with and evade destruction by the host. This review aims to illustrate every aspect of the game between the host and Toxoplasma during the process of infection. A better understanding of all aspects of the battle between Toxoplasma and its hosts will be useful for the development of better strategies and drugs to control the parasite.
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Affiliation(s)
- Wanbo Zhu
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, China.,Graduate School of Affiliated Anhui Provincial Hospital, Anhui Medical University, Hefei, China
| | - Jingyang Li
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, China.,The Clinical Laboratory of the Third People's Hospital of Heifei, Hefei, China
| | - Faustina Pappoe
- Department of Microbiology and Immunology, School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Jilong Shen
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, China
| | - Li Yu
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, China
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Gas-Pascual E, Ichikawa HT, Sheikh MO, Serji MI, Deng B, Mandalasi M, Bandini G, Samuelson J, Wells L, West CM. CRISPR/Cas9 and glycomics tools for Toxoplasma glycobiology. J Biol Chem 2018; 294:1104-1125. [PMID: 30463938 DOI: 10.1074/jbc.ra118.006072] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/12/2018] [Indexed: 01/25/2023] Open
Abstract
Infection with the protozoan parasite Toxoplasma gondii is a major health risk owing to birth defects, its chronic nature, ability to reactivate to cause blindness and encephalitis, and high prevalence in human populations. Unlike most eukaryotes, Toxoplasma propagates in intracellular parasitophorous vacuoles, but like nearly all other eukaryotes, Toxoplasma glycosylates many cellular proteins and lipids and assembles polysaccharides. Toxoplasma glycans resemble those of other eukaryotes, but species-specific variations have prohibited deeper investigations into their roles in parasite biology and virulence. The Toxoplasma genome encodes a suite of likely glycogenes expected to assemble N-glycans, O-glycans, a C-glycan, GPI-anchors, and polysaccharides, along with their precursors and membrane transporters. To investigate the roles of specific glycans in Toxoplasma, here we coupled genetic and glycomics approaches to map the connections between 67 glycogenes, their enzyme products, the glycans to which they contribute, and cellular functions. We applied a double-CRISPR/Cas9 strategy, in which two guide RNAs promote replacement of a candidate gene with a resistance gene; adapted MS-based glycomics workflows to test for effects on glycan formation; and infected fibroblast monolayers to assess cellular effects. By editing 17 glycogenes, we discovered novel Glc0-2-Man6-GlcNAc2-type N-glycans, a novel HexNAc-GalNAc-mucin-type O-glycan, and Tn-antigen; identified the glycosyltransferases for assembling novel nuclear O-Fuc-type and cell surface Glc-Fuc-type O-glycans; and showed that they are important for in vitro growth. The guide sequences, editing constructs, and mutant strains are freely available to researchers to investigate the roles of glycans in their favorite biological processes.
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Affiliation(s)
- Elisabet Gas-Pascual
- Department of Biochemistry and Molecular Biology, Athens, Georgia 30602; Center for Tropical and Emerging Global Diseases, Athens, Georgia 30602
| | | | | | | | - Bowen Deng
- Department of Biochemistry and Molecular Biology, Athens, Georgia 30602; Center for Tropical and Emerging Global Diseases, Athens, Georgia 30602
| | - Msano Mandalasi
- Department of Biochemistry and Molecular Biology, Athens, Georgia 30602; Center for Tropical and Emerging Global Diseases, Athens, Georgia 30602
| | - Giulia Bandini
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, Massachusetts 02118
| | - John Samuelson
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, Massachusetts 02118
| | - Lance Wells
- Department of Biochemistry and Molecular Biology, Athens, Georgia 30602; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Christopher M West
- Department of Biochemistry and Molecular Biology, Athens, Georgia 30602; Center for Tropical and Emerging Global Diseases, Athens, Georgia 30602; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602.
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Tu V, Yakubu R, Weiss LM. Observations on bradyzoite biology. Microbes Infect 2018; 20:466-476. [PMID: 29287987 PMCID: PMC6019562 DOI: 10.1016/j.micinf.2017.12.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 12/13/2017] [Accepted: 12/15/2017] [Indexed: 02/06/2023]
Abstract
Tachyzoites of the Apicomplexan Toxoplasma gondii cause acute infection, disseminate widely in their host, and eventually differentiate into a latent encysted form called bradyzoites that are found within tissue cysts. During latent infection, whenever transformation to tachyzoites occurs, any tachyzoites that develop are removed by the immune system. In contrast, cysts containing bradyzoites are sequestered from the immune system. In the absence of an effective immune response released organisms that differentiate into tachyzoites cause acute infection. Tissue cysts, therefore, serve as a reservoir for the reactivation of toxoplasmosis when the host becomes immunocompromised by conditions such as HIV infection, organ transplantation, or due to the impaired immune response that occurs when pathogens are acquired in utero. While tachyzoites and bradyzoites are well defined morphologically, there is no clear consensus on how interconversion occurs or what exact signal(s) mediate this transformation. Advances in research methods have facilitated studies on T. gondii bradyzoites providing important new insights into the biology of latent infection.
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Affiliation(s)
- Vincent Tu
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Rama Yakubu
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, 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.
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40
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Tomita T, Ma Y, Weiss L. Characterization of a SRS13: a new cyst wall mucin-like domain containing protein. Parasitol Res 2018; 117:2457-2466. [PMID: 29911257 DOI: 10.1007/s00436-018-5934-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 05/15/2018] [Indexed: 12/31/2022]
Abstract
Toxoplasma gondii, an obligate intracellular apicomplexan, causes latent infection in about one third of the human population. During latent infection, T. gondii bradyzoites are found within cysts, a modified parasitophorous vacuole. This parasite has a large family of SRS (surface antigen-1 related sequence) proteins which are reported to be involved in attachment of these organisms to their mammalian host cells and in immune subversion during latent infection. We have identified a novel mucin domain containing SRS protein, using a glycoepitope-specific antibody, which recognizes the cyst wall. SRS13 has two SRS domains and between these domains is a threonine-rich tandem repeat mucin-like domain that is similar to the mucin-like domain seen in another cyst wall specific SRS protein CST1 (SRS44). SRS13 is upregulated in bradyzoites and O-GalNAc glycosylated by ppGalNAc-T2 and T3. Similar to the cyst wall protein CST1, SRS13 localizes to the cyst wall, but unlike CST1, SRS13 is dispensable for normal cyst wall formation. Together, these findings elucidate the role of a second SRS mucin domain protein, SRS13, in bradyzoite biology and expands the previously reported functions of the SRS protein family.
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Affiliation(s)
- Tadakimi Tomita
- Department of Pathology, Albert Einstein College of Medicine, Bronx, 1300 Morris Park Avenue, New York, 10461, USA.
| | - Yanfen Ma
- Department of Pathology, Albert Einstein College of Medicine, Bronx, 1300 Morris Park Avenue, New York, 10461, USA
| | - Louis Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, 1300 Morris Park Avenue, New York, 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, 1300 Morris Park Avenue, New York, 10461, USA
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41
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DeCicco RePass MA, Bhat N, Heimburg-Molinaro J, Bunnell S, Cummings RD, Ward HD. Molecular cloning, expression, and characterization of UDP N-acetyl-α-d-galactosamine: Polypeptide N-acetylgalactosaminyltransferase 4 from Cryptosporidium parvum. Mol Biochem Parasitol 2018; 221:56-65. [PMID: 29581010 DOI: 10.1016/j.molbiopara.2018.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 03/21/2018] [Accepted: 03/21/2018] [Indexed: 01/06/2023]
Abstract
Cryptosporidium spp. are the causative agents of diarrheal disease worldwide, but effective treatments are lacking. Cryptosporidium employs mucin-like glycoproteins with O-glycans to attach to and infect host intestinal epithelial cells. The Tn antigen (GalNAcα1-Ser/Thr) is an O-glycan essential for these processes, as Tn-specific lectins and a Tn-specific monoclonal antibody block attachment to and infection of host cells in vitro. The enzymes in Cryptosporidium catalyzing their synthesis, however, have not been studied. Previously, we identified four genes encoding putative UDP N-acetyl-α-d-galactosamine:polypeptide N-acetylgalactosaminyltransferases (ppGalNAc-Ts) in the genomes of three Cryptosporidium spp. Here we report the in silico analysis, cloning, expression, purification, and characterization of one of the four enzymes Cryptosporidium parvum (Cp)-ppGalNAc-T4. This enzyme contains the characteristic domains and motifs conserved in ppGalNAc-Ts and is expressed at multiple time points during in vitro infection. Recombinant soluble Cp-ppGalNAc-T4 was enzymatically active against an unmodified EA2 peptide suggesting that it may function as an "initiating" ppGalNAc-T. Cp-ppGalNAc-T4 also exhibited a strong preference for UDP-GalNAc over other nucleotide sugar donors and was active against unmodified and O-glycosylated versions of the C. parvum gp40-derived peptide, with a preference for the former, suggesting it may play a role in modifying this glycoprotein in vivo. Given the importance of mucin-type O-glycosylation in Cryptosporidium spp., the enzymes that catalyze their synthesis may serve as potential therapeutic targets.
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Affiliation(s)
| | | | | | - Stephen Bunnell
- Tufts University Sackler School of Graduate Biomedical Sciences, Boston, MA, USA
| | - Richard D Cummings
- Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Honorine D Ward
- Tufts University Sackler School of Graduate Biomedical Sciences, Boston, MA, USA; Tufts Medical Center, Boston, MA, USA.
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Cova M, López-Gutiérrez B, Artigas-Jerónimo S, González-Díaz A, Bandini G, Maere S, Carretero-Paulet L, Izquierdo L. The Apicomplexa-specific glucosamine-6-phosphate N-acetyltransferase gene family encodes a key enzyme for glycoconjugate synthesis with potential as therapeutic target. Sci Rep 2018; 8:4005. [PMID: 29507322 PMCID: PMC5838249 DOI: 10.1038/s41598-018-22441-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 02/22/2018] [Indexed: 02/06/2023] Open
Abstract
Apicomplexa form a phylum of obligate parasitic protozoa of great clinical and veterinary importance. These parasites synthesize glycoconjugates for their survival and infectivity, but the enzymatic steps required to generate the glycosylation precursors are not completely characterized. In particular, glucosamine-phosphate N-acetyltransferase (GNA1) activity, needed to produce the essential UDP-N-acetylglucosamine (UDP-GlcNAc) donor, has not been identified in any Apicomplexa. We scanned the genomes of Plasmodium falciparum and representatives from six additional main lineages of the phylum for proteins containing the Gcn5-related N-acetyltransferase (GNAT) domain. One family of GNAT-domain containing proteins, composed by a P. falciparum sequence and its six apicomplexan orthologs, rescued the growth of a yeast temperature-sensitive GNA1 mutant. Heterologous expression and in vitro assays confirmed the GNA1 enzymatic activity in all lineages. Sequence, phylogenetic and synteny analyses suggest an independent origin of the Apicomplexa-specific GNA1 family, parallel to the evolution of a different GNA1 family in other eukaryotes. The inability to disrupt an otherwise modifiable gene target suggests that the enzyme is essential for P. falciparum growth. The relevance of UDP-GlcNAc for parasite viability, together with the independent evolution and unique sequence features of Apicomplexa GNA1, highlights the potential of this enzyme as a selective therapeutic target against apicomplexans.
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Affiliation(s)
- Marta Cova
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Borja López-Gutiérrez
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Sara Artigas-Jerónimo
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Aida González-Díaz
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Giulia Bandini
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, USA
| | - Steven Maere
- Ghent University, Department of Plant Biotechnology and Bioinformatics, B-9052, Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052, Ghent, Belgium
- Bioinformatics Institute Ghent, Ghent University, B-9052, Ghent, Belgium
| | - Lorenzo Carretero-Paulet
- Ghent University, Department of Plant Biotechnology and Bioinformatics, B-9052, Ghent, Belgium.
- VIB Center for Plant Systems Biology, B-9052, Ghent, Belgium.
- Bioinformatics Institute Ghent, Ghent University, B-9052, Ghent, Belgium.
| | - Luis Izquierdo
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.
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43
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Yakubu RR, Weiss LM, Silmon de Monerri NC. Post-translational modifications as key regulators of apicomplexan biology: insights from proteome-wide studies. Mol Microbiol 2017; 107:1-23. [PMID: 29052917 DOI: 10.1111/mmi.13867] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 10/12/2017] [Accepted: 10/16/2017] [Indexed: 12/12/2022]
Abstract
Parasites of the Apicomplexa phylum, such as Plasmodium spp. and Toxoplasma gondii, undergo complex life cycles involving multiple stages with distinct biology and morphologies. Post-translational modifications (PTMs), such as phosphorylation, acetylation and glycosylation, regulate numerous cellular processes, playing a role in every aspect of cell biology. PTMs can occur on proteins at any time in their lifespan and through alterations of target protein activity, localization, protein-protein interactions, among other functions, dramatically increase proteome diversity and complexity. In addition, PTMs can be induced or removed on changes in cellular environment and state. Thus, PTMs are likely to be key regulators of developmental transitions, biology and pathogenesis of apicomplexan parasites. In this review we examine the roles of PTMs in both parasite-specific and conserved eukaryotic processes, and the potential crosstalk between PTMs, that together regulate the intricate lives of these protozoa.
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Affiliation(s)
- Rama R Yakubu
- Department of Pathology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10128, USA.,Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10128, USA
| | - Louis M Weiss
- Department of Pathology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10128, USA.,Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10128, USA
| | - Natalie C Silmon de Monerri
- Department of Pathology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10128, USA.,Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10128, USA
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44
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Wohlfert EA, Blader IJ, Wilson EH. Brains and Brawn: Toxoplasma Infections of the Central Nervous System and Skeletal Muscle. Trends Parasitol 2017; 33:519-531. [PMID: 28483381 PMCID: PMC5549945 DOI: 10.1016/j.pt.2017.04.001] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/29/2017] [Accepted: 04/08/2017] [Indexed: 02/06/2023]
Abstract
Toxoplasma gondii is a widespread parasitic pathogen that infects over a third of the world's population. Following an acute infection, the parasite can persist within its mammalian host as intraneuronal or intramuscular cysts. Cysts will occasionally reactivate, and - depending on the host's immune status and site of reactivation - encephalitis or myositis can develop. Because these diseases have high levels of morbidity and can be lethal, it is important to understand how Toxoplasma traffics to these tissues, how the immune response controls parasite burden and contributes to tissue damage, and what mechanisms underlie neurological and muscular pathologies that toxoplasmosis patients present with. This review aims to summarize recent important developments addressing these critical topics.
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Affiliation(s)
- Elizabeth A Wohlfert
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, NY, USA.
| | - Ira J Blader
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, NY, USA.
| | - Emma H Wilson
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, USA.
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45
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Watts EA, Dhara A, Sinai AP. Purification Toxoplasma gondii Tissue Cysts Using Percoll Gradients. CURRENT PROTOCOLS IN MICROBIOLOGY 2017; 45:20C.2.1-20C.2.19. [PMID: 28510363 PMCID: PMC5568674 DOI: 10.1002/cpmc.30] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The protozoan parasite Toxoplasma gondii is capable of infecting all warm-blooded animals and humans. Infectious, transmissible forms of the parasite include oocysts produced by the sexual cycle within the definitive feline host and tissue cysts that form Toxoplasma in the central nervous system and muscle during the asexual cycle within all chronically infected warm-blooded hosts. These tissue cysts are populated with slow-growing bradyzoites, which until recently have been thought to be dormant entities in the context of immune sufficiency. Reactivation to active growth during immune suppression is of critical clinical importance. However, little is known about tissue cysts or the bradyzoites they house, as the diversity of tissue cysts cannot be replicated in cell culture systems. This protocol for optimization of tissue cyst purification from the brains of infected mice using Percoll gradients provides an efficient means to recover in vivo-derived tissue cysts that can be applied to imaging, cell biological, biochemical, transcriptomic, and proteomic analyses. © 2017 by John Wiley & Sons, Inc.
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Affiliation(s)
- Elizabeth A Watts
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky
- Current Address: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia
| | - Animesh Dhara
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky
| | - Anthony P Sinai
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky
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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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