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Wulansari D, Jeelani G, Yazaki E, Nozaki T. Identification and characterization of archaeal-type FAD synthase as a novel tractable drug target from the parasitic protozoa Entamoeba histolytica. mSphere 2024; 9:e0034724. [PMID: 39189775 PMCID: PMC11423594 DOI: 10.1128/msphere.00347-24] [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: 04/25/2024] [Accepted: 07/29/2024] [Indexed: 08/28/2024] Open
Abstract
Flavin adenine dinucleotide (FAD) is an essential cofactor for numerous flavoenzymes present in all living organisms. The biosynthesis of FAD from riboflavin involves two sequential reactions catalyzed by riboflavin kinase and flavin adenine dinucleotide synthase (FADS). Entamoeba histolytica, the protozoan parasite responsible for amebiasis, apparently lacks a gene encoding FADS that share similarity with bacterial and eukaryotic canonical FADS, yet it can synthesize FAD. In this study, we have identified the gene responsible for FADS and thoroughly characterized physiological and biochemical properties of FADS from E. histolytica. Phylogenetic analysis revealed that the gene was likely laterally transferred from archaea. The kinetic properties of recombinant EhFADS were consistent with the notion that EhFADS is of archaeal origin, exhibiting KM and kcat values similar to those of the arachaeal enzyme while significantly differing from the human counterpart. Repression of gene expression of EhFADS by epigenetic gene silencing caused substantial reduction in FAD levels and parasite growth, underscoring the importance of EhFADS for the parasite. Furthermore, we demonstrated that EhFADS gene silencing reduced thioredoxin reductase activity, which requires FAD as a cofactor and makes the ameba more susceptible to metronidazole. In summary, this study unveils unique evolutionary and biochemical features of EhFADS and underscores its significance as a promising drug target in combating human amebiasis.IMPORTANCEFAD is important for all forms of life, yet its role and metabolism are still poorly studied in E. histolytica, the protozoan parasite causing human amebiasis. Our study uncovers the evolutionary unique key enzyme, archaeal-type FADS for FAD biosynthesis from E. histolytica for the first time. Additionally, we showed the essentiality of this enzyme for parasite survival, highlighting its potential as target for drug development against E. histolytica infections.
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Affiliation(s)
- Dewi Wulansari
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- National Research and Innovation Agency, Jakarta, Indonesia
| | - Ghulam Jeelani
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Euki Yazaki
- Research Center for Advanced Analysis, National Agriculture and Food Research Organization, Ibaraki, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Watanabe N, Saito-Nakano Y, Kurisawa N, Otomo K, Suenaga K, Nakano K, Nozaki T. Fumagillin inhibits growth of the enteric protozoan parasite Entamoeba histolytica by covalently binding to and selectively inhibiting methionine aminopeptidase 2. Antimicrob Agents Chemother 2023; 67:e0056023. [PMID: 37874291 PMCID: PMC10648944 DOI: 10.1128/aac.00560-23] [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: 05/02/2023] [Accepted: 08/27/2023] [Indexed: 10/25/2023] Open
Abstract
Amebiasis is an important cause of morbidity and mortality worldwide, and caused by infection with the protozoan parasite Entamoeba histolytica. Metronidazole is currently the first-line drug despite adverse effects and concerns on the emergence of drug resistance. Fumagillin, a fungal metabolite from Aspergillus fumigatus, and its structurally related natural and synthetic compounds have been previously explored as potential anti-angiogenesis inhibitors for cancers, anti-microbial, and anti-obese compounds. Although fumagillin was used for human amebiasis in clinical trials in 1950s, the mode of action of fumagillin remains elusive until now. In this report, we showed that fumagillin covalently binds to methionine aminopeptidase 2 (MetAP2) and non-covalently but abundantly binds to patatin family phospholipase A (PLA). Susceptibility against fumagillin of the amebic strains in which expression of E. histolytica MetAP2 (EhMetAP2) gene was silenced increased compared to control strain. Conversely, overexpression of EhMetAP2 mutants that harbors amino acid substitutions responsible for resistance to ovalicin, a fumagillin analog, in human MetAP2, also resulted in decrease in fumagillin susceptibility. In contrast, neither gene silencing nor overexpression of E. histolytica PLA (EhPLA) affected fumagillin susceptibility. These data suggest that EhPLA is not essential and not the target of fumagillin for its amebicidal activity. Taken together, our data have demonstrated that EhMetAP2 is the primary target for amebicidal activity of fumagillin, and EhMetAP2 represents a rational explorable target for the development of alternative therapeutic agents against amebiasis.
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Affiliation(s)
- Natsuki Watanabe
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yumiko Saito-Nakano
- Department of Parasitology and Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Naoaki Kurisawa
- Department of Chemistry, Faculty of Science and Technology, Keio University, Kanagawa, Japan
| | - Keisuke Otomo
- Department of Chemistry, Faculty of Science and Technology, Keio University, Kanagawa, Japan
| | - Kiyotake Suenaga
- Department of Chemistry, Faculty of Science and Technology, Keio University, Kanagawa, Japan
| | - Kentaro Nakano
- Degree Programs in Biology, Graduate School of Science and Technology, University of Tsukuba, Ibaraki, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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3
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Jeelani G, Balogun EO, Husain A, Nozaki T. Glycerol biosynthetic pathway plays an essential role in proliferation and antioxidative defense in the human enteric protozoan parasite Entamoeba histolytica. Sci Rep 2023; 13:14596. [PMID: 37669981 PMCID: PMC10480196 DOI: 10.1038/s41598-023-40670-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 08/16/2023] [Indexed: 09/07/2023] Open
Abstract
Amebiasis is caused by the protozoan parasite Entamoeba histolytica. Treatment options other than metronidazole and its derivatives are few, and their low efficacy against asymptomatic cyst carriers, and experimental evidence of resistance in vitro justify the discovery/repurposing campaign for new drugs against amebiasis. Global metabolic responses to oxidative stress and cysteine deprivation by E. histolytica revealed glycerol metabolism may represent a rational target for drug development. In this study using 14C-labelled glucose, only 11% of the total glucose taken up by E. histolytica trophozoites is incorporated to lipids. To better understand the role of glycerol metabolism in this parasite, we focused on characterizing two important enzymes, glycerol kinase (GK) and glycerol 3-phosphate dehydrogenase (G3PDH). Recombinant GK was biochemically characterized in detail, while G3PDH was not due to failure of protein expression and purification. GK revealed novel characteristics and unprecedented kinetic properties in reverse reaction. Gene silencing revealed that GK is essential for optimum growth, whereas G3PDH is not. Gene silencing of G3PDH caused upregulated GK expression, while that of GK resulted in upregulation of antioxidant enzymes as shown by RNA-seq analysis. Although the precise molecular link between GK and the upregulation of antioxidant enzymes was not demonstrated, the observed increase in antioxidant enzyme expression upon GK gene silencing suggests a potential connection between GK and the cellular response to oxidative stress. Together, these results provide the first direct evidence of the biological importance and coordinated regulation of the glycerol metabolic pathways for proliferation and antioxidative defense in E. histolytica, justifying the exploitation of these enzymes as future drug targets.
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Affiliation(s)
- Ghulam Jeelani
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Emmanuel Oluwadare Balogun
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria
| | - Afzal Husain
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, India
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
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Lozano-Mendoza J, Ramírez-Montiel F, Rangel-Serrano Á, Páramo-Pérez I, Mendoza-Macías CL, Saavedra-Salazar F, Franco B, Vargas-Maya N, Jeelani G, Saito-Nakano Y, Anaya-Velázquez F, Nozaki T, Padilla-Vaca F. Attenuation of In Vitro and In Vivo Virulence Is Associated with Repression of Gene Expression of AIG1 Gene in Entamoeba histolytica. Pathogens 2023; 12:pathogens12030489. [PMID: 36986411 PMCID: PMC10051847 DOI: 10.3390/pathogens12030489] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 02/27/2023] [Accepted: 03/02/2023] [Indexed: 03/30/2023] Open
Abstract
Entamoeba histolytica virulence results from complex host-parasite interactions implicating multiple amoebic components (e.g., Gal/GalNAc lectin, cysteine proteinases, and amoebapores) and host factors (microbiota and immune response). UG10 is a strain derived from E. histolytica virulent HM-1:IMSS strain that has lost its virulence in vitro and in vivo as determined by a decrease of hemolytic, cytopathic, and cytotoxic activities, increased susceptibility to human complement, and its inability to form liver abscesses in hamsters. We compared the transcriptome of nonvirulent UG10 and its parental HM-1:IMSS strain. No differences in gene expression of the classical virulence factors were observed. Genes downregulated in the UG10 trophozoites encode for proteins that belong to small GTPases, such as Rab and AIG1. Several protein-coding genes, including iron-sulfur flavoproteins and heat shock protein 70, were also upregulated in UG10. Overexpression of the EhAIG1 gene (EHI_180390) in nonvirulent UG10 trophozoites resulted in augmented virulence in vitro and in vivo. Cocultivation of HM-1:IMSS with E. coli O55 bacteria cells reduced virulence in vitro, and the EhAIG1 gene expression was downregulated. In contrast, virulence was increased in the monoxenic strain UG10, and the EhAIG1 gene expression was upregulated. Therefore, the EhAIG1 gene (EHI_180390) represents a novel virulence determinant in E. histolytica.
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Affiliation(s)
- Janeth Lozano-Mendoza
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato 36050, Mexico
| | - Fátima Ramírez-Montiel
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato 36050, Mexico
| | - Ángeles Rangel-Serrano
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato 36050, Mexico
| | - Itzel Páramo-Pérez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato 36050, Mexico
| | | | - Faridi Saavedra-Salazar
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato 36050, Mexico
| | - Bernardo Franco
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato 36050, Mexico
| | - Naurú Vargas-Maya
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato 36050, Mexico
| | - Ghulam Jeelani
- Graduate School of Medicine, The University of Tokyo, Tokyo 113-8654, Japan
| | - Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo 162-0052, Japan
| | - Fernando Anaya-Velázquez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato 36050, Mexico
| | - Tomoyoshi Nozaki
- Graduate School of Medicine, The University of Tokyo, Tokyo 113-8654, Japan
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo 162-0052, Japan
| | - Felipe Padilla-Vaca
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato 36050, Mexico
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Nakada-Tsukui K, Watanabe N, Shibata K, Wahyuni R, Miyamoto E, Nozaki T. Proteomic analysis of Atg8-dependent recruitment of phagosomal proteins in the enteric protozoan parasite Entamoeba histolytica. Front Cell Infect Microbiol 2022; 12:961645. [PMID: 36262186 PMCID: PMC9575557 DOI: 10.3389/fcimb.2022.961645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
Autophagy is one of the bulk degradation systems and is conserved throughout eukaryotes. In the enteric protozoan parasite Entamoeba histolytica, the causative agent of human amebiasis, Atg8 is not exclusively involved in autophagy per se but also in other membrane traffic-related pathways such as phagosome biogenesis. We previously reported that repression of atg8 gene expression by antisense small RNA-mediated transcriptional gene silencing (gs) resulted in growth retardation, delayed endocytosis, and reduced acidification of endosomes and phagosomes. In this study, to better understand the role of Atg8 in phagocytosis and trogocytosis, we conducted a comparative proteomic analysis of phagosomes isolated from wild type and atg8-gs strains. We found that 127 and 107 proteins were detected >1.5-fold less or more abundantly, respectively, in phagosomes isolated from the atg8-gs strain, compared to the control strain. Among 127 proteins whose abundance was reduced in phagosomes from atg8-gs, a panel of proteins related to fatty acid metabolism, phagocytosis, and endoplasmic reticulum (ER) homeostasis was identified. Various lysosomal hydrolases and their receptors also tend to be excluded from phagosomes by atg8-gs, reinforcing the notion that Atg8 is involved in phagosomal acidification and digestion. On the contrary, among 107 proteins whose abundance increased in phagosomes from atg8-gs strain, ribosome-related proteins and metabolite interconversion enzymes are enriched. We further investigated the localization of several representative proteins, including adenylyl cyclase-associated protein and plasma membrane calcium pump, both of which were demonstrated to be recruited to phagosomes and trogosomes via an Atg8-dependent mechanism. Taken together, our study has provided the basis of the phagosome proteome to further elucidate molecular events in the Atg8-dependent regulatory network of phagosome/trogosome biogenesis in E. histolytica.
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Affiliation(s)
- Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
- *Correspondence: Kumiko Nakada-Tsukui, ; Tomoyoshi Nozaki,
| | - Natsuki Watanabe
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kumiko Shibata
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Ratna Wahyuni
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Eri Miyamoto
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- *Correspondence: Kumiko Nakada-Tsukui, ; Tomoyoshi Nozaki,
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Idrees D, Naqvi AAT, Hassan MI, Ahmad F, Gourinath S. Insight into the Conformational Transitions of Serine Acetyl Transferase Isoforms in E. histolytica: Implications for Structural and Functional Balance. ACS OMEGA 2022; 7:24626-24637. [PMID: 35874230 PMCID: PMC9301732 DOI: 10.1021/acsomega.2c02467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Serine acetyl transferase (SAT) is one of the crucial enzymes in the cysteine biosynthetic pathway and an essential enzyme for the survival of Entamoeba histolytica, the causative agent of amoebiasis. E. histolytica expresses three isoforms of SAT, where SAT1 and SAT2 are inhibited by the final product cysteine, while SAT3 is not inhibited. SAT3 has a slightly elongated C-terminus compared to SAT1. To understand the stability and conformational transition between two secondary structures of proteins, we measured the effect of urea, a chemical denaturant, on two isoforms of SAT (SAT1 and SAT3) of E. histolytica. The effect of urea on the structure and stability of SAT1 and SAT3 was determined by measuring changes in their far-UV circular dichroism (CD), Trp fluorescence, and near-UV absorption spectra. The urea-induced normal transition curves suggested that the structural transition is reversible and follows a two-state process. Analysis of the urea-induced transition of all optical properties for the stability parameters ΔG D° (Gibbs free energy change (ΔG D) in the absence of urea), m (dependence of ΔG D on urea concentration), and C m (midpoint of urea transition) suggested that SAT1 is more stable than SAT3. Characterization of the end product of the urea-induced transition of both proteins by the far-UV CD and Trp-fluorescence and near-UV absorbance suggested that urea causes α-helix to β-sheet transition and burial of Trp residues, respectively. To support the in vitro findings, 100 ns molecular dynamics simulations (in silico study) were performed. Both the spectroscopic and molecular dynamics approaches clearly indicated that SAT1 is more stable than SAT3. SAT3 has evolved to escape the feedback inhibition to keep producing cysteine, but in the process, it compromises its structural stability relative to SAT1.
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Affiliation(s)
- Danish Idrees
- School
of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
- Faculty
of Allied Health Sciences, Shree Guru Gobind
Tricentenary University, Gurugram, Harayana 122505, India
| | | | - Md Imtaiyaz Hassan
- Centre
for Interdisciplinary Research in Basic Science, Jamia Millia Islamia, New Delhi 110025, India
| | - Faizan Ahmad
- Department
of Biochemistry, Jamia Hamdard, New Delhi 110062, India
| | - Samudrala Gourinath
- School
of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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Kadri S, Nakada-Tsukui K, Watanabe N, Jeelani G, Nozaki T. PTEN differentially regulates endocytosis, migration, and proliferation in the enteric protozoan parasite Entamoeba histolytica. PLoS Pathog 2022; 18:e1010147. [PMID: 35500038 PMCID: PMC9122207 DOI: 10.1371/journal.ppat.1010147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 05/20/2022] [Accepted: 04/04/2022] [Indexed: 11/18/2022] Open
Abstract
PTEN is a lipid phosphatase that is highly conserved and involved in a broad range of biological processes including cytoskeletal reorganization, endocytosis, signal transduction, and cell migration in all eukaryotes. Although regulation of phosphatidylinositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P3] signaling via PTEN has been well established in model organisms and mammals, it remains elusive in the parasitic protist E. histolytica, which heavily relies on PtdIns phosphate(s)-dependent membrane traffic, migration, and phago- and trogocytosis for its pathogenesis. In this study, we characterized the major PTEN from E. histolytica, EhPTEN1, which shows the highest expression at the transcript level in the trophozoite stage among 6 possible PTENs, to understand the significance of PtdIns(3,4,5)P3 signaling in this parasite. Live imaging of GFP-EhPTEN1 expressing amebic trophozoites showed localization mainly in the cytosol with a higher concentration at pseudopods and the extending edge of the phago- and trogocytic cups. Furthermore, quantitative analysis of phago- and trogocytosis using a confocal image cytometer showed that overexpression of EhPTEN1 caused reduction in trogo- and phagocytosis while transcriptional gene silencing of EhPTEN1 gene caused opposite phenotypes. These data suggest that EhPTEN1 has an inhibitory role in these biological processes. Conversely, EhPTEN1 acts as a positive regulator for fluid-phase and receptor-mediated endocytosis in E. histolytica trophozoites. Moreover, we showed that EhPTEN1 was required for optimal growth and migration of this parasite. Finally, the phosphatase activity of EhPTEN1 towards PtdIns(3,4,5)P3 was demonstrated, suggesting that the biological roles of EhPTEN1 are likely linked to its catalytic function. Taken together, these results indicate that EhPTEN1 differentially regulates multiple cellular activities essential for proliferation and pathogenesis of the organism, via PtdIns(3,4,5)P3 signaling. Elucidation of biological roles of PTEN and PtdIns(3,4,5)P3 signaling at the molecular levels promotes our understanding of the pathogenesis of this parasite.
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Affiliation(s)
- Samia Kadri
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Natsuki Watanabe
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Ghulam Jeelani
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- * E-mail:
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Abstract
Interorganellar cross talk is often mediated by membrane contact sites (MCSs), which are zones where participating membranes come within 30 nm of one another. MCSs have been found in organelles, including the endoplasmic reticulum, Golgi bodies, endosomes, and mitochondria. Despite its seeming ubiquity, reports of MCS involving mitochondrion-related organelles (MROs) present in a few anaerobic parasitic protozoa remain lacking. Entamoeba histolytica, the etiological agent of amoebiasis, possesses an MRO called the mitosome. We previously discovered several Entamoeba-specific transmembrane mitosomal proteins (ETMPs) from in silico and cell-biological analyses. One of them, ETMP1 (EHI_175060), was predicted to have one transmembrane domain and two coiled-coil regions and was demonstrated to be mitosome membrane integrated based on carbonate fractionation and immunoelectron microscopy (IEM) data. Immunoprecipitation analysis detected a candidate interacting partner, EH domain-containing protein (EHD1; EHI_105270). We expressed hemagglutinin (HA)-tagged EHD1 in E. histolytica, and subsequent immunofluorescence and IEM data indicated an unprecedented MCS between the mitosome and the endosome. Live imaging of a green fluorescent protein (GFP)-EHD1-expressing strain demonstrated that EHD1 is involved in early endosome formation and is observed in MCS between endosomes of various sizes. In vitro assays using recombinant His-EHD1 demonstrated ATPase activity. MCSs are involved in lipid transfer, ion homeostasis, and organelle dynamics. The serendipitous discovery of the ETMP1-interacting partner EHD1 led to the observation of the mitosome-endosome contact site in E. histolytica. It opened a new view of how the relic mitochondria of Entamoeba may likewise be involved in organelle cross talk, a conserved feature of mitochondria and other organelles in general.
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Promoter-Bound Full-Length Intronic Circular RNAs-RNA Polymerase II Complexes Regulate Gene Expression in the Human Parasite Entamoeba histolytica. Noncoding RNA 2022; 8:ncrna8010012. [PMID: 35202086 PMCID: PMC8876499 DOI: 10.3390/ncrna8010012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 12/12/2022] Open
Abstract
Ubiquitous eukaryotic non-coding circular RNAs are involved in numerous co- and post-transcriptional regulatory mechanisms. Recently, we reported full-length intronic circular RNAs (flicRNAs) in Entamoeba histolytica, with 3′ss–5′ss ligation points and 5′ss GU-rich elements essential for their biogenesis and their suggested role in transcription regulation. Here, we explored how flicRNAs impact gene expression regulation. Using CLIP assays, followed by qRT-PCR, we identified that the RabX13 control flicRNA and virulence-associated flicRNAs were bound to the HA-tagged RNA Pol II C-terminus domain in E. histolytica transformants. The U2 snRNA was also present in such complexes, indicating that they belonged to transcription initiation/elongation complexes. Correspondingly, inhibition of the second step of splicing using boric acid reduced flicRNA formation and modified the expression of their parental genes and non-related genes. flicRNAs were also recovered from chromatin immunoprecipitation eluates, indicating that the flicRNA-Pol II complex was formed in the promoter of their cognate genes. Finally, two flicRNAs were found to be cytosolic, whose functions remain to be uncovered. Here, we provide novel evidence of the role of flicRNAs in gene expression regulation in cis, apparently in a widespread fashion, as an element bound to the RNA polymerase II transcription initiation complex, in E. histolytica.
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Peng R, Yoshinari S, Kawano-Sugaya T, Jeelani G, Nozaki T. Identification and Functional Characterization of Divergent 3'-Phosphate tRNA Ligase From Entamoeba histolytica. Front Cell Infect Microbiol 2022; 11:746261. [PMID: 34976851 PMCID: PMC8718801 DOI: 10.3389/fcimb.2021.746261] [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: 07/23/2021] [Accepted: 11/24/2021] [Indexed: 11/13/2022] Open
Abstract
HSPC117/RtcB, 3'-phosphate tRNA ligase, is a critical enzyme involved in tRNA splicing and maturation. HSPC117/RtcB is also involved in mRNA splicing of some protein-coding genes including XBP-1. Entamoeba histolytica, a protozoan parasite responsible for human amebiasis, possesses two RtcB proteins (EhRtcB1 and 2), but their biological functions remain unknown. Both RtcBs show kinship with mammalian/archaeal type, and all amino acid residues present in the active sites are highly conserved, as suggested by protein alignment and phylogenetic analyses. EhRtcB1 was demonstrated to be localized to the nucleus, while EhRtcB2 was in the cytosol. EhRtcB1, but not EhRtcB2, was required for optimal growth of E. histolytica trophozoites. Both EhRtcB1 (in cooperation with EhArchease) and EhRtcB2 showed RNA ligation activity in vitro. The predominant role of EhRtcB1 in tRNAIle(UAU) processing in vivo was demonstrated in EhRtcB1- and 2-gene silenced strains. Taken together, we have demonstrated the conservation of tRNA splicing and functional diversification of RtcBs in this amoebozoan lineage.
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Affiliation(s)
- Ruofan Peng
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shigeo Yoshinari
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tetsuro Kawano-Sugaya
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Ghulam Jeelani
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tomoyoshi Nozaki
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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11
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Saito-Nakano Y, Makiuchi T, Tochikura M, Gilchrist CA, Petri WA, Nozaki T. ArfX2 GTPase Regulates Trafficking From the Trans-Golgi to Lysosomes and Is Necessary for Liver Abscess Formation in the Protozoan Parasite Entamoeba histolytica. Front Cell Infect Microbiol 2022; 11:794152. [PMID: 34976870 PMCID: PMC8719317 DOI: 10.3389/fcimb.2021.794152] [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: 10/13/2021] [Accepted: 11/24/2021] [Indexed: 02/03/2023] Open
Abstract
Entamoeba histolytica is the causative agent of amoebic dysentery and liver abscess in humans. The parasitic lifestyle and the virulence of the protist require elaborate biological processes, including vesicular traffic and stress management against a variety of reactive oxygen and nitrogen species produced by the host immune response. Although the mechanisms for intracellular traffic of representative virulence factors have been investigated at molecular levels, it remains poorly understood whether and how intracellular traffic is involved in the defense against reactive oxygen and nitrogen species. Here, we demonstrate that EhArfX2, one of the Arf family of GTPases known to be involved in the regulation of vesicular traffic, was identified by comparative transcriptomic analysis of two isogenic strains: an animal-passaged highly virulent HM-1:IMSS Cl6 and in vitro maintained attenuated avirulent strain. EhArfX2 was identified as one of the most highly upregulated genes in the highly virulent strain. EhArfX2 was localized to small vesicle-like structures and largely colocalized with the marker for the trans-Golgi network SNARE, EhYkt6, but neither with the endoplasmic reticulum (ER)-resident chaperon, EhBip, nor the cis-Golgi SNARE, EhSed5, and Golgi-luminal galactosyl transferase, EhGalT. Expression of the dominant-active mutant form of EhArfX2 caused an increase in the number of lysosomes, while expression of the dominant-negative mutant led to a defect in lysosome formation and cysteine protease transport to lysosomes. Expression of the dominant-negative mutant in the virulent E. histolytica strain caused a reduction of the size of liver abscesses in a hamster model. This defect in liver abscess formation was likely at least partially attributed to reduced resistance to nitrosative, but not oxidative stress in vitro. These results showed that the EhArfX2-mediated traffic is necessary for the nitrosative stress response and virulence in the host.
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Affiliation(s)
- Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - Takashi Makiuchi
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Mami Tochikura
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - Carol A Gilchrist
- Department of Medicine, University of Virginia, Charlottesville, VA, United States
| | - William A Petri
- Department of Medicine, University of Virginia, Charlottesville, VA, United States
| | - Tomoyoshi Nozaki
- Graduate School of Medicine, The University of Tokyo, Bunkyo, Tokyo, Japan
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12
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Jeelani G, Nozaki T. Eukaryotic translation initiation factor 5A and its posttranslational modifications play an important role in proliferation and potentially in differentiation of the human enteric protozoan parasite Entamoeba histolytica. PLoS Pathog 2021; 17:e1008909. [PMID: 33592076 PMCID: PMC7909649 DOI: 10.1371/journal.ppat.1008909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 02/26/2021] [Accepted: 01/19/2021] [Indexed: 11/19/2022] Open
Abstract
The eukaryotic translation initiation factor 5A (eIF5A) is a highly conserved protein and is essential in all eukaryotes. However, the specific roles of eIF5A in translation and in other biological processes remain elusive. In the present study, we described the role of eIF5A, its posttranslational modifications (PTM), and the biosynthetic pathway needed for the PTM in Entamoeba histolytica, the protozoan parasite responsible for amoebic dysentery and liver abscess in humans. E. histolytica encodes two isotypes of eIF5A and two isotypes of enzymes, deoxyhypusine synthase (DHS), responsible for their PTM. Both of the two eIF5A isotypes are functional, whereas only one DHS (EhDHS1, but not EhDHS2), is catalytically active. The DHS activity increased ~2000-fold when EhDHS1 was co-expressed with EhDHS2 in Escherichia coli, suggesting that the formation of a heteromeric complex is needed for full enzymatic activity. Both EhDHS1 and 2 genes were required for in vitro growth of E. histolytica trophozoites, indicated by small antisense RNA-mediated gene silencing. In trophozoites, only eIF5A2, but not eIF5A1, gene was actively transcribed. Gene silencing of eIF5A2 caused compensatory induction of expression of eIF5A1 gene, suggesting interchangeable role of the two eIF5A isotypes and also reinforcing the importance of eIF5As for parasite proliferation and survival. Furthermore, using a sibling species, Entamoeba invadens, we found that eIF5A1 gene was upregulated during excystation, while eIF5A2 was downregulated, suggesting that eIF5A1 gene plays an important role during differentiation. Taken together, these results have underscored the essentiality of eIF5A and DHS, for proliferation and potentially in the differentiation of this parasite, and suggest that the hypusination associated pathway represents a novel rational target for drug development against amebiasis.
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Affiliation(s)
- Ghulam Jeelani
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Japan
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13
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Low molecular weight protein tyrosine phosphatase (LMW-PTP2) protein can potentially modulate virulence of the parasite Entamoeba histolytica. Mol Biochem Parasitol 2021; 242:111360. [PMID: 33428948 DOI: 10.1016/j.molbiopara.2021.111360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/22/2020] [Accepted: 01/05/2021] [Indexed: 02/06/2023]
Abstract
The Entamoeba histolytica parasite is the causative agent of amebiasis, infecting approximately 1% of the world population and causing 100,000 deaths per year. It binds to Fibronectin (FN), activating signaling pathways regulated by kinases and phosphatases. EhLMW-PTPs genes from E. histolytica encode for Low Molecular Weight Tyrosine Phosphatases expressed in trophozoites and amoebic cysts. The role of these phosphatases in the virulence of the parasite has not yet been well characterized. Our results showed a differential expression of the EhLMW-PTPs, at the mRNA and protein levels, in an asynchronous trophozoites culture. Furthermore, we observed that trophozoites transfected that overexpressed EhLMW-PTP2 phagocytized fewer erythrocytes, possibly due to decreased phagocytic cups, and showed deficiencies in adherence to FN and less cytopathic effect. These analyzes suggest that the parasite's EhLMW-PTPs have an essential role in the mechanisms of proliferation, adhesion, and phagocytosis, regulating its pathogenicity.
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14
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Saito-Nakano Y, Wahyuni R, Nakada-Tsukui K, Tomii K, Nozaki T. Rab7D small GTPase is involved in phago-, trogocytosis and cytoskeletal reorganization in the enteric protozoan Entamoeba histolytica. Cell Microbiol 2020; 23:e13267. [PMID: 32975360 PMCID: PMC7757265 DOI: 10.1111/cmi.13267] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/21/2020] [Accepted: 09/18/2020] [Indexed: 12/12/2022]
Abstract
Rab small GTPases regulate membrane traffic between distinct cellular compartments of all eukaryotes in a tempo‐spatially specific fashion. Rab small GTPases are also involved in the regulation of cytoskeleton and signalling. Membrane traffic and cytoskeletal regulation play pivotal role in the pathogenesis of Entamoeba histolytica, which is a protozoan parasite responsible for human amebiasis. E. histolytica is unique in that its genome encodes over 100 Rab proteins, containing multiple isotypes of conserved members (e.g., Rab7) and Entamoeba‐specific subgroups (e.g., RabA, B, and X). Among them, E. histolytica Rab7 is the most diversified group consisting of nine isotypes. While it was previously demonstrated that EhRab7A and EhRab7B are involved in lysosome and phagosome biogenesis, the individual roles of other Rab7 members and their coordination remain elusive. In this study, we characterised the third member of Rab7, Rab7D, to better understand the significance of the multiplicity of Rab7 isotypes in E. histolytica. Overexpression of EhRab7D caused reduction in phagocytosis of erythrocytes, trogocytosis (meaning nibbling or chewing of a portion) of live mammalian cells, and phagosome acidification and maturation. Conversely, transcriptional gene silencing of EhRab7D gene caused opposite phenotypes in phago/trogocytosis and phagosome maturation. Furthermore, EhRab7D gene silencing caused reduction in the attachment to and the motility on the collagen‐coated surface. Image analysis showed that EhRab7D was occasionally associated with lysosomes and prephagosomal vacuoles, but not with mature phagosomes and trogosomes. Finally, in silico prediction of structural organisation of EhRab7 isotypes identified unique amino acid changes on the effector binding surface of EhRab7D. Taken together, our data suggest that EhRab7D plays coordinated counteracting roles: a inhibitory role in phago/trogocytosis and lyso/phago/trogosome biogenesis, and an stimulatory role in adherence and motility, presumably via interaction with unique effectors. Finally, we propose the model in which three EhRab7 isotypes are sequentially involved in phago/trogocytosis.
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Affiliation(s)
- Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Ratna Wahyuni
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia.,Department of Health, Faculty of Vocational Studies, Universitas Airlangga, Surabaya, Indonesia
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kentaro Tomii
- Artificial Intelligence Research Center (AIRC) and Real World Big-Data Computation Open Innovation Laboratory (RWBC-OIL), National Institute of Advance Industrial Science and Technology (AIST), Tokyo, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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15
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Import of Entamoeba histolytica Mitosomal ATP Sulfurylase Relies on Internal Targeting Sequences. Microorganisms 2020; 8:microorganisms8081229. [PMID: 32806678 PMCID: PMC7465240 DOI: 10.3390/microorganisms8081229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/11/2020] [Accepted: 08/11/2020] [Indexed: 11/17/2022] Open
Abstract
Mitochondrial matrix proteins synthesized in the cytosol often contain amino (N)-terminal targeting sequences (NTSs), or alternately internal targeting sequences (ITSs), which enable them to be properly translocated to the organelle. Such sequences are also required for proteins targeted to mitochondrion-related organelles (MROs) that are present in a few species of anaerobic eukaryotes. Similar to other MROs, the mitosomes of the human intestinal parasite Entamoeba histolytica are highly degenerate, because a majority of the components involved in various processes occurring in the canonical mitochondria are either missing or modified. As of yet, sulfate activation continues to be the only identified role of the relic mitochondria of Entamoeba. Mitosomes influence the parasitic nature of E. histolytica, as the downstream cytosolic products of sulfate activation have been reported to be essential in proliferation and encystation. Here, we investigated the position of the targeting sequence of one of the mitosomal matrix enzymes involved in the sulfate activation pathway, ATP sulfurylase (AS). We confirmed by immunofluorescence assay and subcellular fractionation that hemagluttinin (HA)-tagged EhAS was targeted to mitosomes. However, its ortholog in the δ-proteobacterium Desulfovibrio vulgaris, expressed as DvAS-HA in amoebic trophozoites, indicated cytosolic localization, suggesting a lack of recognizable mitosome targeting sequence in this protein. By expressing chimeric proteins containing swapped sequences between EhAS and DvAS in amoebic cells, we identified the ITSs responsible for mitosome targeting of EhAS. This observation is similar to other parasitic protozoans that harbor MROs, suggesting a convergent feature among various MROs in favoring ITS for the recognition and translocation of targeted proteins.
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Watanabe N, Nakada-Tsukui K, Maehama T, Nozaki T. Dynamism of PI4-Phosphate during Interactions with Human Erythrocytes in Entamoeba histolytica. Microorganisms 2020; 8:microorganisms8071050. [PMID: 32679800 PMCID: PMC7409237 DOI: 10.3390/microorganisms8071050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 12/20/2022] Open
Abstract
Phosphatidylinositol phosphates (PIPs) are involved in many cellular events as important secondary messengers. In Entamoeba histolytica, a human intestinal protozoan parasite, virulence-associated mechanisms such as cell motility, vesicular traffic, trogo- and phagocytosis are regulated by PIPs. It has been well established that PI3P, PI4P, and PI(3,4,5)P3 play specific roles during amoebic trogo- and phagocytosis. In the present study, we demonstrated the nuclear localization of PI4P in E. histolytica trophozoites in steady state with immunofluorescence imaging and immunoelectron microscopy, using anti-PI4P antibodies and PI4P biosensors [substrate of the Icm/ Dot type IV secretion system (SidM)]. We further showed that the nuclear PI4P decreased after a co-culture with human erythrocytes or Chinese hamster ovary (CHO) cells. However, concomitant changes in the localization and the amount of PI(4,5)P2, which is the expected major metabolized (phosphorylated) product of PI4P, were not observed. This phenomenon was specifically caused by whole or ghost erythrocytes and CHO cells, but not artificial beads. The amount of PIP2 and PIP, biochemically estimated by [32P]-phosphate metabolic labeling and thin layer chromatography, was decreased upon erythrocyte adherence. Altogether, our data indicate for the first time in eukaryotes that erythrocyte attachment leads to the metabolism of nuclear PIPs, and metabolites other than PI(4,5)P2 may be involved in the regulation of downstream cellular events such as cytoskeleton rearrangement or transcriptional regulation.
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Affiliation(s)
- Natsuki Watanabe
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan;
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan;
| | - Tomohiko Maehama
- Division of Molecular and Cellular Biology, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan;
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan;
- Correspondence: ; Tel.: +81-3-5841-3526
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17
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Shahzadi Z, Abbas G, Azam SS. Relational dynamics obtained through simulation studies of thioredoxin reductase: From a multi-drug resistant Entamoeba histolytica. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.112939] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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18
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Watanabe N, Nakada-Tsukui K, Nozaki T. Two isotypes of phosphatidylinositol 3-phosphate-binding sorting nexins play distinct roles in trogocytosis in Entamoeba histolytica. Cell Microbiol 2019; 22:e13144. [PMID: 31713312 PMCID: PMC7027479 DOI: 10.1111/cmi.13144] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 09/23/2019] [Accepted: 11/07/2019] [Indexed: 12/27/2022]
Abstract
Phosphatidylinositol phosphates (PIPs) function as important second messengers in many cellular events. In the human intestinal protist Entamoeba histolytica, where phagocytosis/trogocytosis plays an indispensable role in proliferation and pathophysiology during infection, various PIPs are involved in multiple steps of phago/trogocytosis. PI3‐phosphate (PI3P) plays a pivotal role in the biogenesis of phagosome/trogosomes via recruitment of PI3P effectors. Because no known PI3P downstream effectors are conserved in E. histolytica, we exploited a unique method to identify the proteins PI3P dependently recruited to phagosomes. We rationalised that overexpression of PI3P‐binding GFP‐HrsFYVE competes for PI3P on phagosomal membranes and results in dissociation of PI3P effectors from phagosomes. EhVps26 and EhVps35, but not sorting nexins (SNXs), of the retromer complex were detected from phagosomes only without GFP‐HrsFYVE overexpression. Two potential SNXs, EhSNX1 and EhSNX2, identified in the genome, possess only phox homology domain and specifically bound to PI3P, but retromer components, EhVps26 and EhVps35, did not bind to PI3P. Live and immunofluorescence imaging showed that EhSNX1 was recruited to the trogocytic cup and tunnel‐like structures, and subsequently, EhSNX2 was recruited to trogosomes. Furthermore, EhSNX1, but not EhSNX2, specifically bound to Arp2/3 and EhVps26, which were localised to the tunnel‐like structures and the trogosomes, respectively. EhSNX2 gene silencing increased trogocytosis, suggesting that EhSNX2 plays an inhibitory role in trogocytosis.
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Affiliation(s)
- Natsuki Watanabe
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan.,Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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19
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Ramírez-Montiel F, Mendoza-Macías C, Andrade-Guillén S, Rangel-Serrano Á, Páramo-Pérez I, Rivera-Cuéllar PE, España-Sánchez BL, Luna-Bárcenas G, Anaya-Velázquez F, Franco B, Padilla-Vaca F. Plasma membrane damage repair is mediated by an acid sphingomyelinase in Entamoeba histolytica. PLoS Pathog 2019; 15:e1008016. [PMID: 31461501 PMCID: PMC6713333 DOI: 10.1371/journal.ppat.1008016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 08/02/2019] [Indexed: 12/15/2022] Open
Abstract
Entamoeba histolytica is a pathogen that during its infective process confronts the host defenses, which damages the amoebic plasma membrane (PM), resulting in the loss of viability. However, it is unknown whether amoebic trophozoites are able to repair their PM when it is damaged. Acid sphingomyelinases (aSMases) have been reported in mammalian cells to promote endocytosis and removal of PM lesions. In this work, six predicted amoebic genes encoding for aSMases were found to be transcribed in the HM1:IMSS strain, finding that the EhaSM6 gene is the most transcribed in basal growth conditions and rendered a functional protein. The secreted aSMase activity detected was stimulated by Mg+2 and inhibited by Co+2. Trophozoites that overexpress the EhaSM6 gene (HM1-SM6HA) exhibit an increase of 2-fold in the secreted aSMase activity. This transfectant trophozoites exposed to pore-forming molecules (SLO, Magainin, β-Defensin 2 and human complement) exhibited an increase from 6 to 25-fold in the secreted aSMase activity which correlated with higher amoebic viability in a Ca+2 dependent process. However, other agents that affect the PM such as hydrogen peroxide also induced an increase of secreted aSMase, but to a lesser extent. The aSMase6 enzyme is N- and C-terminal processed. Confocal and transmission electron microscopy showed that trophozoites treated with SLO presented a migration of lysosomes containing the aSMase towards the PM, inducing the formation of membrane patches and endosomes in the control strain. These cellular structures were increased in the overexpressing strain, indicating the involvement of the aSMase6 in the PM injury repair. The pore-forming molecules induced an increase in the expression of EhaSM1, 2, 5 and 6 genes, meanwhile, hydrogen peroxide induced an increase in all of them. In all the conditions evaluated, the EhaSM6 gene exhibited the highest levels of induction. Overall, these novel findings show that the aSMase6 enzyme from E. histolytica promotes the repair of the PM damaged with pore-forming molecules to prevent losing cell integrity. This novel system could act when encountered with the lytic defense systems of the host. The host-amoeba relationship is based on a series of interplays between host defense mechanisms and parasite survival strategies. While host cells elaborate diverse mechanisms for pathogen elimination, Entamoeba histolytica trophozoites have also developed complex strategies to counteract host immune response and facilitate its own survival while confronting host defenses. E. histolytica exposed to pore-forming proteins such as β-Defensin 2, human complement and Streptolysin O (SLO), increases the activity of secreted aSMase, which is related to greater amoebic viability. Other agents that affect plasma membrane (PM) may also increase secreted aSMase but to a lesser extent. SLO form pores in the PM of E. histolytica trophozoites that initiates the uncontrolled entry of Ca2+, recognized as the primary trigger for cell responses which favors the migration of the lysosomes to the periphery of the cell, fuses with the PM and release their content, including aSMase to the external side of the cell. The secreted aSMase favoring the internalization of the lesion for its degradation in phagolysosomes. During the early stages of PM damage, the pores are rapidly blocked by patch-like structures that prevent the lysis of the trophozoite and immediately begin internalizing the lesion. The aSMase6 overexpression favors the repair of the lesion and the survival of E. histolytica trophozoites. Pore-forming proteins induced an increase in the expression of EhaSM1, 2, 5 and 6 genes, meanwhile oxidative stress induced an increase in all of them. Here we report, for the first time, that E. histolytica possess a mechanism for PM damage repair mediated by aSMase similar to the system described in mammalian cells.
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Affiliation(s)
- Fátima Ramírez-Montiel
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - Claudia Mendoza-Macías
- Departmento de Farmacia, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - Sairy Andrade-Guillén
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - Ángeles Rangel-Serrano
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - Itzel Páramo-Pérez
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - Paris E. Rivera-Cuéllar
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - B. Liliana España-Sánchez
- CONACYT_Centro de Investigación y Desarrollo en Electroquímica (CIDETEQ) S.C. Parque Tecnológico, San Fandila, Querétaro, México
| | - Gabriel Luna-Bárcenas
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV) Unidad Querétaro, Fracc. Real de Juriquilla, Querétaro, Querétaro, México
| | - Fernando Anaya-Velázquez
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - Bernardo Franco
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
- * E-mail: (BF); (FPV)
| | - Felipe Padilla-Vaca
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
- * E-mail: (BF); (FPV)
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Structural and functional characterisation of phosphoserine phosphatase, that plays critical role in the oxidative stress response in the parasite Entamoeba histolytica. J Struct Biol 2019; 206:254-266. [DOI: 10.1016/j.jsb.2019.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/25/2019] [Accepted: 03/29/2019] [Indexed: 02/02/2023]
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21
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N-terminal residues are crucial for quaternary structure and active site conformation for the phosphoserine aminotransferase from enteric human parasite E. histolytica. Int J Biol Macromol 2019; 132:1012-1023. [PMID: 30959130 DOI: 10.1016/j.ijbiomac.2019.04.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/04/2019] [Accepted: 04/04/2019] [Indexed: 11/24/2022]
Abstract
Phosphoserine aminotransferase (PSAT) is a pyridoxal-5'phosphate (PLP)-dependent enzyme that catalyzes the second reversible step in the phosphoserine biosynthetic pathway producing serine. The crystal structure of E. histolytica PSAT (EhPSAT) complexed with PLP was elucidated at 3.0 Å resolution and the structures of its mutants, EhPSAT_Δ45 and EhPSAT_Δ4, at 1.8 and 2.4 Å resolution respectively. Deletion of 45 N-terminal residues (EhPSAT_Δ45) resulted in an inactive protein, the structure showed a dimeric arrangement drastically different from that of the wild-type protein, with the two monomers translated and rotated by almost 180° with respect to each other; causing a rearrangement of the active site to which PLP was unable to bind. Deletion of first N-terminal 15 (EhPSAT_Δ15) and four 11th to 14th residues (EhPSAT_Δ4) yielded up to 98% and 90% decrease in the activity respectively. Absence of aldimine linkage between PLP-Lys in the crystal structure of EhPSAT_Δ4 mutant explains for such decrease in activity and describes the importance of these N-terminal residues. Furthermore, a halide-binding site was found in close proximity to the active site. A stretch of six amino acids (146-NNTIYG-151) only conserved in the Entamoeba genus, contributes to halide binding may explain that the halide inhibition could be specific to Entamoeba.
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Control and regulation of the pyrophosphate-dependent glucose metabolism in Entamoeba histolytica. Mol Biochem Parasitol 2019; 229:75-87. [PMID: 30772421 DOI: 10.1016/j.molbiopara.2019.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/31/2019] [Accepted: 02/09/2019] [Indexed: 01/10/2023]
Abstract
Entamoeba histolytica has neither Krebs cycle nor oxidative phosphorylation activities; therefore, glycolysis is the main pathway for ATP supply and provision of carbon skeleton precursors for the synthesis of macromolecules. Glucose is metabolized through fermentative glycolysis, producing ethanol as its main end-product as well as some acetate. Amoebal glycolysis markedly differs from the typical Embden-Meyerhof-Parnas pathway present in human cells: (i) by the use of inorganic pyrophosphate, instead of ATP, as the high-energy phospho group donor; (ii) with one exception, the pathway enzymes can catalyze reversible reactions under physiological conditions; (iii) there is no allosteric regulation and sigmoidal kinetic behavior of key enzymes; and (iv) the presence of some glycolytic and fermentation enzymes similar to those of anaerobic bacteria. These peculiarities bring about alternative mechanisms of control and regulation of the PPi-dependent fermentative glycolysis in the parasite in comparison to the ATP-dependent and allosterically regulated glycolysis in many other eukaryotic cells. In this review, the current knowledge of the carbohydrate metabolism enzymes in E. histolytica is analyzed. Thermodynamics and stoichiometric analyses indicate 2 to 3.5 ATP yield per glucose metabolized, instead of the often presumed 5 ATP/glucose ratio. PPi derived from anabolism seems insufficient for PPi-glycolysis; hence, alternative ways of PPi supply are also discussed. Furthermore, the underlying mechanisms of control and regulation of the E. histolytica carbohydrate metabolism, analyzed by applying integral and systemic approaches such as Metabolic Control Analysis and kinetic modeling, contribute to unveiling alternative and promising drug targets.
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Mori M, Tsuge S, Fukasawa W, Jeelani G, Nakada-Tsukui K, Nonaka K, Matsumoto A, Ōmura S, Nozaki T, Shiomi K. Discovery of Antiamebic Compounds That Inhibit Cysteine Synthase From the Enteric Parasitic Protist Entamoeba histolytica by Screening of Microbial Secondary Metabolites. Front Cell Infect Microbiol 2018; 8:409. [PMID: 30568921 PMCID: PMC6290340 DOI: 10.3389/fcimb.2018.00409] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 11/01/2018] [Indexed: 01/21/2023] Open
Abstract
Amebiasis is caused by infection with the protozoan parasite Entamoeba histolytica. Although metronidazole has been a drug of choice against amebiasis for decades, it shows side effects and low efficacy against asymptomatic cyst carriers. In addition, metronidazole resistance has been documented for bacteria and protozoa that share its targets, anaerobic energy metabolism. Therefore, drugs with new mode of action or targets are urgently needed. L-cysteine is the major thiol and an essential amino acid for proliferation and anti-oxidative defense of E. histolytica trophozoites. E. histolytica possesses the de novo L-cysteine biosynthetic pathway, consisting of two reactions catalyzed by serine acetyltransferase and cysteine synthase (CS, O-acetylserine sulfhydrylase). As the pathway is missing in humans, it is considered to be a rational drug target against amebiasis. In this study, we established a protocol to screen both a library of structurally known compounds and microbial culture extracts to discover compounds that target de novo cysteine biosynthesis of E. histolytica. The new screening system allowed us to identify the compounds that differentially affect the growth of the trophozoites in the cysteine-deprived medium compared to the cysteine-containing medium. A total of 431 structurally defined compounds of the Kitasato Natural Products Library and 6,900 microbial culture broth extracts were screened on the system described above. Five compounds, aspochalasin B, chaetoglobosin A, prochaetoglobosin III, cerulenin, and deoxyfrenolicin, from the Kitasato Natural Products Library, showed differential antiamebic activities in the cysteine-deprived medium when compared to the growth in the cysteine-containing medium. The selectivity of three cytochalasans apparently depends on their structural instability. Eleven microbial extracts showed selective antiamebic activities, and one fungal secondary metabolite, pencolide, was isolated. Pencolide showed cysteine deprivation-dependent antiamebic activity (7.6 times lower IC50 in the absence of cysteine than that in the presence of cysteine), although the IC50 value in the cysteine-deprived medium was rather high (283 μM). Pencolide also showed inhibitory activity against both CS1 and CS3 isoenzymes with comparable IC50 values (233 and 217 μM, respectively). These results indicated that antiamebic activity of pencolide is attributable to inhibition of CS. Cytotoxicity of pencolide was 6.7 times weaker against mammalian MRC-5 cell line than E. histotytica. Pencolide has the maleimide structure, which is easily attacked by Michael donors including the thiol moiety of cysteine. The cysteine-adducts of pencolide were detected by mass spectrometric analysis as predicted. As CS inhibition by the pencolide adducts was weak and their IC50 values to CS was comparable to that to the parasite in the cysteine-containing medium, the cysteine-adducts of pencolide likely contribute to toxicity of pencolide to the parasite in the cysteine-rich conditions. However, we cannot exclude a possibility that pencolide inactivates a variety of targets other than CSs in the absence of cysteine. Taken together, pencolide is the first compound that inhibits CS and amebic cell growth in a cysteine-dependent manner with relatively low mammalian cytotoxicity.
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Affiliation(s)
- Mihoko Mori
- Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan
- Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan
| | - Satoshi Tsuge
- Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan
| | - Wataru Fukasawa
- Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan
| | - Ghulam Jeelani
- Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kenichi Nonaka
- Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan
- Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan
| | - Atsuko Matsumoto
- Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan
- Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan
| | - Satoshi Ōmura
- Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan
| | - Tomoyoshi Nozaki
- Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kazuro Shiomi
- Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan
- Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan
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Nurkanto A, Jeelani G, Yamamoto T, Hishiki T, Naito Y, Suematsu M, Hashimoto T, Nozaki T. Biochemical, Metabolomic, and Genetic Analyses of Dephospho Coenzyme A Kinase Involved in Coenzyme A Biosynthesis in the Human Enteric Parasite Entamoeba histolytica. Front Microbiol 2018; 9:2902. [PMID: 30555442 PMCID: PMC6284149 DOI: 10.3389/fmicb.2018.02902] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/13/2018] [Indexed: 11/14/2022] Open
Abstract
Coenzyme A (CoA) is an essential cofactor for numerous cellular reactions in all living organisms. In the protozoan parasite Entamoeba histolytica, CoA is synthesized in a pathway consisting of four enzymes with dephospho-CoA kinase (DPCK) catalyzing the last step. However, the metabolic and physiological roles of E. histolytica DPCK remain elusive. In this study, we took biochemical, reverse genetic, and metabolomic approaches to elucidate role of DPCK in E. histolytica. The E. histolytica genome encodes two DPCK isotypes (EhDPCK1 and EhDPCK2). Epigenetic gene silencing of Ehdpck1 and Ehdpck2 caused significant reduction of DPCK activity, intracellular CoA concentrations, and also led to growth retardation in vitro, suggesting importance of DPCK for CoA synthesis and proliferation. Furthermore, metabolomic analysis showed that suppression of Ehdpck gene expression also caused decrease in the level of acetyl-CoA, and metabolites involved in amino acid, glycogen, hexosamine, nucleic acid metabolisms, chitin, and polyamine biosynthesis. The kinetic properties of E. histolytica and human DPCK showed remarkable differences, e.g., the Km values of E. histolytica and human DPCK were 58-114 and 5.2 μM toward dephospho-CoA and 15-20 and 192 μM for ATP, respectively. Phylogenetic analysis also supported the uniqueness of the amebic enzyme compared to the human counterpart. These biochemical, evolutionary features, and physiological importance of EhDPCKs indicate that EhDPCK represents the rational target for the development of anti-amebic agents.
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Affiliation(s)
- Arif Nurkanto
- Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
- Research Center for Biology, Indonesia Institute of Sciences (LIPI), Cibinong, Indonesia
| | - Ghulam Jeelani
- Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Takehiro Yamamoto
- Department of Biochemistry, School of Medicine, Keio University, Tokyo, Japan
| | - Takako Hishiki
- Department of Biochemistry, School of Medicine, Keio University, Tokyo, Japan
- Clinical and Translational Research Center, School of Medicine, Keio University, Tokyo, Japan
| | - Yoshiko Naito
- Clinical and Translational Research Center, School of Medicine, Keio University, Tokyo, Japan
| | - Makoto Suematsu
- Department of Biochemistry, School of Medicine, Keio University, Tokyo, Japan
| | - Tetsuo Hashimoto
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Tomoyoshi Nozaki
- Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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25
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Hanadate Y, Saito-Nakano Y, Nakada-Tsukui K, Nozaki T. Identification and Characterization of the Entamoeba Histolytica Rab8a Binding Protein: A Cdc50 Homolog. Int J Mol Sci 2018; 19:ijms19123831. [PMID: 30513690 PMCID: PMC6321534 DOI: 10.3390/ijms19123831] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 11/24/2018] [Accepted: 11/27/2018] [Indexed: 12/31/2022] Open
Abstract
Membrane traffic plays a pivotal role in virulence in the enteric protozoan parasite Entamoeba histolytica. EhRab8A small GTPase is a key regulator of membrane traffic at the endoplasmic reticulum (ER) of this protist and is involved in the transport of plasma membrane proteins. Here we identified the binding proteins of EhRab8A. The Cdc50 homolog, a non-catalytic subunit of lipid flippase, was identified as an EhRab8A binding protein candidate by affinity coimmunoprecipitation. Binding of EhRab8A to EhCdc50 was also confirmed by reciprocal immunoprecipitation and blue-native polyacrylamide gel electrophoresis, the latter of which revealed an 87 kDa complex. Indirect immunofluorescence imaging with and without Triton X100 showed that endogenous EhCdc50 localized on the surface in the absence of permeabilizing agent but was observed on the intracellular structures and overlapped with the ER marker Bip when Triton X100 was used. Overexpression of N-terminal HA-tagged EhCdc50 impaired its translocation to the plasma membrane and caused its accumulation in the ER. As reported previously in other organisms, overexpression and accumulation of Cdc50 in the ER likely inhibited surface transport and function of the plasma membrane lipid flippase P4-ATPase. Interestingly, HA-EhCdc50-expressing trophozoites gained resistance to miltefosine, which is consistent with the prediction that HA-EhCdc50 overexpression caused its accumulation in the ER and mislocalization of the unidentified lipid flippase. Similarly, EhRab8A gene silenced trophozoites showed increased resistance to miltefosine, supporting EhRab8A-dependent transport of EhCdc50. This study demonstrated for the first time that EhRab8A mediates the transport of EhCdc50 and lipid flippase P4-ATPase from the ER to the plasma membrane.
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Affiliation(s)
- Yuki Hanadate
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
| | - Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
- Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan.
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Wu D, Feng M, Wang ZX, Qiao K, Tachibana H, Cheng XJ. Molecular and biochemical characterization of key enzymes in the cysteine and serine metabolic pathways of Acanthamoeba castellanii. Parasit Vectors 2018; 11:604. [PMID: 30477573 PMCID: PMC6257972 DOI: 10.1186/s13071-018-3188-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/06/2018] [Indexed: 11/30/2022] Open
Abstract
Background Acanthamoeba spp. can cause serious human infections, including Acanthamoeba keratitis, granulomatous amoebic encephalitis and cutaneous acanthamoebiasis. Cysteine biosynthesis and the L-serine metabolic pathway play important roles in the energy metabolism of Acanthamoeba spp. However, no study has confirmed the functions of cysteine synthase (AcCS) in the cysteine pathway and phosphoglycerate dehydrogenase (AcGDH) or phosphoserine aminotransferase (AcSPAT) in the non-phosphorylation serine metabolic pathway of Acanthamoeba. Methods The AcCS, AcGDH and AcSPAT genes were amplified by PCR, and their recombinant proteins were expressed in Escherichia coli. Polyclonal antibodies against the recombinant proteins were prepared in mice and used to determine the subcellular localisation of each native protein by confocal laser scanning microscopy. The enzymatic activity of each recombinant protein was also analysed. Furthermore, each gene expression level was analysed by quantitative PCR after treatment with different concentrations of cysteine or L-serine. Results The AcCS gene encodes a 382-amino acid protein with a predicted molecular mass of 43.1 kDa and an isoelectric point (pI) of 8.11. The AcGDH gene encodes a 350-amino acid protein with a predicted molecular mass of 39.1 kDa and a pI of 5.51. The AcSPAT gene encodes a 354-amino acid protein with a predicted molecular mass of 38.3 kDa and a pI of 6.26. Recombinant AcCS exhibited a high cysteine synthesis activity using O-acetylserine and Na2S as substrates. Both GDH and SPAT catalysed degradation, rather than synthesis, of serine. Exogenous L-serine or cysteine inhibited the expression of all three enzymes in a time- and dose-dependent manner. Conclusions This study demonstrated that AcCS participates in cysteine biosynthesis and serine degradation via the non-phosphorylation serine metabolic pathway, providing a molecular basis for the discovery of novel anti-Acanthamoeba drugs. Electronic supplementary material The online version of this article (10.1186/s13071-018-3188-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Duo Wu
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Meng Feng
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Zhi-Xin Wang
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Ke Qiao
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Hiroshi Tachibana
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa, 259-1193, Japan
| | - Xun-Jia Cheng
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.
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27
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Mendoza-Figueroa MS, Alfonso-Maqueira EE, Vélez C, Azuara-Liceaga EI, Zárate S, Villegas-Sepúlveda N, Saucedo-Cárdenas O, Valdés J. Postsplicing-Derived Full-Length Intron Circles in the Protozoan Parasite Entamoeba histolytica. Front Cell Infect Microbiol 2018; 8:255. [PMID: 30123775 PMCID: PMC6085484 DOI: 10.3389/fcimb.2018.00255] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022] Open
Abstract
Noncoding circular RNAs are widespread in the tree of life. Particularly, intron-containing circular RNAs which apparently upregulate their parental gene expression. Entamoeba histolytica, the causative agent of dysentery and liver abscesses in humans, codes for several noncoding RNAs, including circular ribosomal RNAs, but no intron containing circular RNAs have been described to date. Divergent RT-PCR and diverse molecular approaches, allowed us to detect bona fide full-length intronic circular RNA (flicRNA) molecules. Self-splicing reactions, RNA polymerase II inhibition with Actinomycin D, and second step of splicing-inhibition with boric acid showed that the production of flicRX13 (one of the flicRNAs found in this work, and our test model) depends on mRNA synthesis and pre-mRNA processing instead of self-splicing. To explore the cues and factors involved in flicRX13 biogenesis in vivo, splicing assays were carried out in amoeba transformants where splicing factors and Dbr1 (intron lariat debranching enzyme 1) were silenced or overexpressed, or where Rabx13 wild-type and mutant 5'ss (splice site) and branch site minigene constructs were overexpressed. Whereas SF1 (splicing factor 1) is not involved, the U2 auxiliary splicing factor, Dbr1, and the GU-rich 5'ss are involved in postsplicing flicRX13 biogenesis, probably by Dbr1 stalling, in a similar fashion to the formation of ciRNAs (circular intronic RNAs), but with distinctive 5'-3'ss ligation points. Different from the reported functions of ciRNAs, the 5'ss GU-rich element of flicRX13 possibly interacts with transcription machinery to silence its own gene in cis. Furthermore, introns of E. histolytica virulence-related genes are also processed as flicRNAs.
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Affiliation(s)
- María S Mendoza-Figueroa
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Eddy E Alfonso-Maqueira
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Cristina Vélez
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Elisa I Azuara-Liceaga
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de Mexico, Mexico City, Mexico
| | - Selene Zárate
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de Mexico, Mexico City, Mexico
| | - Nicolás Villegas-Sepúlveda
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Odila Saucedo-Cárdenas
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico.,División de Genética, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Mexico
| | - Jesús Valdés
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
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28
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Functional Characterization and Structure-Guided Mutational Analysis of the Transsulfuration Enzyme Cystathionine γ-Lyase from Toxoplasma gondii. Int J Mol Sci 2018; 19:ijms19072111. [PMID: 30036991 PMCID: PMC6073527 DOI: 10.3390/ijms19072111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 07/13/2018] [Accepted: 07/17/2018] [Indexed: 11/17/2022] Open
Abstract
Sulfur-containing amino acids play essential roles in many organisms. The protozoan parasite Toxoplasma gondii includes the genes for cystathionine β-synthase and cystathionine γ-lyase (TgCGL), as well as for cysteine synthase, which are crucial enzymes of the transsulfuration and de novo pathways for cysteine biosynthesis, respectively. These enzymes are specifically expressed in the oocyst stage of T. gondii. However, their functionality has not been investigated. Herein, we expressed and characterized the putative CGL from T. gondii. Recombinant TgCGL almost exclusively catalyses the α,γ-hydrolysis of l-cystathionine to form l-cysteine and displays marginal reactivity toward l-cysteine. Structure-guided homology modelling revealed two striking amino acid differences between the human and parasite CGL active-sites (Glu59 and Ser340 in human to Ser77 and Asn360 in toxoplasma). Mutation of Asn360 to Ser demonstrated the importance of this residue in modulating the specificity for the catalysis of α,β- versus α,γ-elimination of l-cystathionine. Replacement of Ser77 by Glu completely abolished activity towards l-cystathionine. Our results suggest that CGL is an important functional enzyme in T. gondii, likely implying that the reverse transsulfuration pathway is operative in the parasite; we also probed the roles of active-site architecture and substrate binding conformations as determinants of reaction specificity in transsulfuration enzymes.
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29
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Torres-Cifuentes DM, Galindo-Rosales JM, Saucedo-Cárdenas O, Valdés J. The Entamoeba histolytica Syf1 Homolog Is Involved in the Splicing of AG-Dependent and AG-Independent Transcripts. Front Cell Infect Microbiol 2018; 8:229. [PMID: 30038900 PMCID: PMC6046404 DOI: 10.3389/fcimb.2018.00229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 06/18/2018] [Indexed: 02/04/2023] Open
Abstract
Syf1 is a tetratricopeptide repeat (TPR) protein implicated in transcription elongation, spliceosome conformation, mRNA nuclear-cytoplasmic export and transcription-coupled DNA repair. Recently, we identified the spliceosomal components of the human parasite Entamoeba histolytica, among them is EhSyf. Molecular predictions confirmed that EhSyf contains 15 type 1 TPR tandem α-antiparallel array motifs. Amoeba transformants carrying plasmids overexpressing HA-tagged or EhSyf silencing plasmids were established to monitor the impact of EhSyf on the splicing of several test Entamoeba transcripts. EhSyf Entamoeba transformants efficiently silenced or overexpressed the proteins in the nucleus. The overexpression or absence of EhSyf notably enhanced or blocked splicing of transcripts irrespective of the strength of their 3′ splice site. Finally, the absence of EhSyf negatively affected the transcription of an intron-less transcript. Altogether our data suggest that EhSyf is a bona fide Syf1 ortholog involved in transcription and splicing.
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Affiliation(s)
- Diana M Torres-Cifuentes
- RNA Laboratory, Department of Biochemistry, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - José M Galindo-Rosales
- RNA Laboratory, Department of Biochemistry, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Odila Saucedo-Cárdenas
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico.,División de Genética, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Mexico
| | - Jesús Valdés
- RNA Laboratory, Department of Biochemistry, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
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30
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Leitsch D, Williams CF, Hrdý I. Redox Pathways as Drug Targets in Microaerophilic Parasites. Trends Parasitol 2018; 34:576-589. [PMID: 29807758 DOI: 10.1016/j.pt.2018.04.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 04/27/2018] [Accepted: 04/28/2018] [Indexed: 01/06/2023]
Abstract
The microaerophilic parasites Entamoeba histolytica, Trichomonas vaginalis, and Giardia lamblia jointly cause hundreds of millions of infections in humans every year. Other microaerophilic parasites such as Tritrichomonas foetus and Spironucleus spp. pose a relevant health problem in veterinary medicine. Unfortunately, vaccines against these pathogens are unavailable, but their microaerophilic lifestyle opens opportunities for specifically developed chemotherapeutics. In particular, their high sensitivity towards oxygen can be exploited by targeting redox enzymes. This review focusses on the redox pathways of microaerophilic parasites and on drugs, either already in use or currently in the state of development, which target these pathways.
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Affiliation(s)
- David Leitsch
- Institute for Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology, and Immunology, Medical University of Vienna, Austria.
| | - Catrin F Williams
- School of Engineering, Cardiff University, Cardiff, Wales, United Kingdom
| | - Ivan Hrdý
- Department of Parasitology, Charles University, Faculty of Science, Prague, Czech Republic
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31
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Nurkanto A, Jeelani G, Yamamoto T, Naito Y, Hishiki T, Mori M, Suematsu M, Shiomi K, Hashimoto T, Nozaki T. Characterization and validation of Entamoeba histolytica pantothenate kinase as a novel anti-amebic drug target. Int J Parasitol Drugs Drug Resist 2018; 8:125-136. [PMID: 29518650 PMCID: PMC6114107 DOI: 10.1016/j.ijpddr.2018.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 02/19/2018] [Accepted: 02/22/2018] [Indexed: 11/02/2022]
Abstract
The Coenzyme A (CoA), as a cofactor involved in >100 metabolic reactions, is essential to the basic biochemistry of life. Here, we investigated the CoA biosynthetic pathway of Entamoeba histolytica (E. histolytica), an enteric protozoan parasite responsible for human amebiasis. We identified four key enzymes involved in the CoA pathway: pantothenate kinase (PanK, EC 2.7.1.33), bifunctional phosphopantothenate-cysteine ligase/decarboxylase (PPCS-PPCDC), phosphopantetheine adenylyltransferase (PPAT) and dephospho-CoA kinase (DPCK). Cytosolic enzyme PanK, was selected for further biochemical, genetic, and phylogenetic characterization. Since E. histolytica PanK (EhPanK) is physiologically important and sufficiently divergent from its human orthologs, this enzyme represents an attractive target for the development of novel anti-amebic chemotherapies. Epigenetic gene silencing of PanK resulted in a significant reduction of PanK activity, intracellular CoA concentrations, and growth retardation in vitro, reinforcing the importance of this gene in E. histolytica. Furthermore, we screened the Kitasato Natural Products Library for inhibitors of recombinant EhPanK, and identified 14 such compounds. One compound demonstrated moderate inhibition of PanK activity and cell growth at a low concentration, as well as differential toxicity towards E. histolytica and human cells.
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Affiliation(s)
- Arif Nurkanto
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan; Department of Parasitology, National Institute of Infectious Diseases (NIID), Tokyo, Japan; Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Japan; Research Center for Biology, Indonesia Institute of Sciences (LIPI), Cibinong, Indonesia
| | - Ghulam Jeelani
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Japan
| | - Takehiro Yamamoto
- Department of Biochemistry, School of Medicine, Keio University, Tokyo, Japan
| | - Yoshiko Naito
- Clinical and Translational Research Center, Keio University School of Medicine, Japan
| | - Takako Hishiki
- Department of Biochemistry, School of Medicine, Keio University, Tokyo, Japan; Clinical and Translational Research Center, Keio University School of Medicine, Japan
| | - Mihoko Mori
- Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan
| | - Makoto Suematsu
- Department of Biochemistry, School of Medicine, Keio University, Tokyo, Japan
| | - Kazuro Shiomi
- Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan
| | - Tetsuo Hashimoto
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Japan.
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Nakada-Tsukui K, Sekizuka T, Sato-Ebine E, Escueta-de Cadiz A, Ji DD, Tomii K, Kuroda M, Nozaki T. AIG1 affects in vitro and in vivo virulence in clinical isolates of Entamoeba histolytica. PLoS Pathog 2018; 14:e1006882. [PMID: 29554130 PMCID: PMC5884625 DOI: 10.1371/journal.ppat.1006882] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 04/04/2018] [Accepted: 01/17/2018] [Indexed: 11/17/2022] Open
Abstract
The disease state of amebiasis, caused by Entamoeba histolytica, varies from asymptomatic to severe manifestations that include dysentery and extraintestinal abscesses. The virulence factors of the pathogen, and host defense mechanisms, contribute to the outcomes of infection; however, the underlying genetic factors, which affect clinical outcomes, remain to be fully elucidated. To identify these genetic factors in E. histolytica, we used Illumina next-generation sequencing to conduct a comparative genomic analysis of two clinical isolates obtained from diarrheal and asymptomatic patients (strains KU50 and KU27, respectively). By mapping KU50 and KU27 reads to the genome of a reference HM-1:IMSS strain, we identified two genes (EHI_089440 and EHI_176590) that were absent in strain KU27. In KU27, a single AIG1 (avrRpt2-induced gene 1) family gene (EHI_176590) was found to be deleted, from a tandem array of three AIG1 genes, by homologous recombination between the two flanking genes. Overexpression of the EHI_176590 gene, in strain HM-1:IMSS cl6, resulted in increased formation of cell-surface protrusions and enhanced adhesion to human erythrocytes. The EHI_176590 gene was detected by PCR in 56% of stool samples from symptomatic patients infected with E. histolytica, but only in 15% of stool samples from asymptomatic individuals. This suggests that the presence of the EHI_176590 gene is correlated with the outcomes of infection. Taken together, these data strongly indicate that the AIG1 family protein plays a pivotal role in E. histolytica virulence via regulation of host cell adhesion. Our in-vivo experiments, using a hamster liver abscess model, showed that overexpression or gene silencing of EHI_176590 reduced and increased liver abscess formation, respectively. This suggests that the AIG1 genes may have contrasting roles in virulence depending on the genetic background of the parasite and host environment.
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Affiliation(s)
- Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tsuyoshi Sekizuka
- Laboratory of Bacterial Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Emi Sato-Ebine
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Dar-der Ji
- Center for Research and Diagnostics, Centers for Disease Control, Taipei, Taiwan
| | - Kentaro Tomii
- Artificial Intelligence Research Center (AIRC) and Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| | - Makoto Kuroda
- Laboratory of Bacterial Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Yeon JY, Yoo SJ, Takagi H, Kang HA. A Novel Mitochondrial Serine O-Acetyltransferase, OpSAT1, Plays a Critical Role in Sulfur Metabolism in the Thermotolerant Methylotrophic Yeast Ogataea parapolymorpha. Sci Rep 2018; 8:2377. [PMID: 29402922 PMCID: PMC5799214 DOI: 10.1038/s41598-018-20630-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/22/2018] [Indexed: 12/03/2022] Open
Abstract
In most bacteria and plants, direct biosynthesis of cysteine from sulfide via O-acetylserine (OAS) is essential to produce sulfur amino acids from inorganic sulfur. Here, we report the functional analysis of a novel mitochondrial serine O-acetyltransferase (SAT), responsible for converting serine into OAS, in the thermotolerant methylotrophic yeast Ogataea parapolymorpha. Domain analysis of O. parapolymorpha SAT (OpSat1p) and other fungal SATs revealed that these proteins possess a mitochondrial targeting sequence (MTS) at the N-terminus and an α/β hydrolase 1 domain at the C-terminal region, which is quite different from the classical SATs of bacteria and plants. Noticeably, OpSat1p is functionally interchangeable with Escherichia coli SAT, CysE, despite that it displays much less enzymatic activity, with marginal feedback inhibition by cysteine, compared to CysE. The Opsat1Δ-null mutant showed remarkably reduced intracellular levels of cysteine and glutathione, implying OAS generation defect. The MTS of OpSat1p directs the mitochondrial targeting of a reporter protein, thus, supporting the localization of OpSat1p in the mitochondria. Intriguingly, the OpSat1p variant lacking MTS restores the OAS auxotrophy, but not the cysteine auxotrophy of the Opsat1Δ mutant strain. This is the first study on a mitochondrial SAT with critical function in sulfur assimilatory metabolism in fungal species.
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Affiliation(s)
- Ji Yoon Yeon
- Department of Life Science, Chung-Ang University, Seoul, 06974, Korea
| | - Su Jin Yoo
- Department of Life Science, Chung-Ang University, Seoul, 06974, Korea
| | - Hiroshi Takagi
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0192, Japan.
| | - Hyun Ah Kang
- Department of Life Science, Chung-Ang University, Seoul, 06974, Korea.
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Jeelani G, Sato D, Soga T, Nozaki T. Genetic, metabolomic and transcriptomic analyses of the de novo L-cysteine biosynthetic pathway in the enteric protozoan parasite Entamoeba histolytica. Sci Rep 2017; 7:15649. [PMID: 29142277 PMCID: PMC5688106 DOI: 10.1038/s41598-017-15923-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 11/01/2017] [Indexed: 11/09/2022] Open
Abstract
The de novo L-cysteine biosynthetic pathway is critical for the growth, antioxidative stress defenses, and pathogenesis of bacterial and protozoan pathogens, such as Salmonella typhimurium and Entamoeba histolytica. This pathway involves two key enzymes, serine acetyltransferase (SAT) and cysteine synthase (CS), which are absent in mammals and therefore represent rational drug targets. The human parasite E. histolytica possesses three SAT and CS isozymes; however, the specific roles of individual isoforms and significance of such apparent redundancy remains unclear. In the present study, we generated E. histolytica cell lines in which CS and SAT expression was knocked down by transcriptional gene silencing. The strain in which CS1, 2 and 3 were simultaneously silenced and the SAT3 gene-silenced strain showed impaired growth when cultured in a cysteine lacking BI-S-33 medium, whereas silencing of SAT1 and SAT2 had no effects on growth. Combined transcriptomic and metabolomic analyses revealed that, CS and SAT3 are involved in S-methylcysteine/cysteine synthesis. Furthermore, silencing of the CS1-3 or SAT3 caused upregulation of various iron-sulfur flavoprotein genes. Taken together, these results provide the first direct evidence of the biological importance of SAT3 and CS isoforms in E. histolytica and justify the exploitation of these enzymes as potential drug targets.
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Affiliation(s)
- Ghulam Jeelani
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo, 162-8640, Japan
| | - Dan Sato
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
- Graduate School of Science and Technology, Department of Applied Biology, Kyoto Institute of Technology, Kyoto, 606-8585, Japan
| | - Tomoyoshi Soga
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo, 162-8640, Japan.
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan.
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35
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Kazama M, Ogiwara S, Makiuchi T, Yoshida K, Nakada-Tsukui K, Nozaki T, Tachibana H. Behavior of DNA-lacking mitochondria in Entamoeba histolytica revealed by organelle transplant. Sci Rep 2017; 7:44273. [PMID: 28287148 PMCID: PMC5347163 DOI: 10.1038/srep44273] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 02/07/2017] [Indexed: 12/19/2022] Open
Abstract
The anaerobic protozoan parasite Entamoeba histolytica has mitosomes that are mitochondria lacking some canonical functions and organelle DNA. Mitosomes play an important role in the life cycle of the parasite. The distribution of proteins in mitosomes is not uniform, and how mitosomes are maintained and retained is unknown. To answer these questions, we developed a transplant method for mitosomes with hemagglutinin-tagged protein into recipient cells containing mitosomes with Myc-tagged protein. Immunofluorescence staining showed that the two protein tags colocalized in single mitosomes in some recipient cells. These results suggest that our transplant method can be used in anaerobic protozoa and that donor mitosomes may obtain recipient proteins through fusion with other mitosomes or through de novo synthesis of proteins in recipient cells.
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Affiliation(s)
- Makoto Kazama
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan
| | - Sanae Ogiwara
- Support Center for Medical Research and Education, Tokai University, Isehara, Kanagawa 259-1193, Japan
| | - Takashi Makiuchi
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan
| | - Kazuhiro Yoshida
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8577, Japan
| | - Hiroshi Tachibana
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan
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Singh K, Ali V, Pratap Singh K, Gupta P, Suman SS, Ghosh AK, Bimal S, Pandey K, Das P. Deciphering the interplay between cysteine synthase and thiol cascade proteins in modulating Amphotericin B resistance and survival of Leishmania donovani under oxidative stress. Redox Biol 2017; 12:350-366. [PMID: 28288415 PMCID: PMC5349463 DOI: 10.1016/j.redox.2017.03.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 03/03/2017] [Indexed: 12/13/2022] Open
Abstract
Leishmania donovani is the causative organism of the neglected human disease known as visceral leishmaniasis which is often fatal, if left untreated. The cysteine biosynthesis pathway of Leishmania may serve as a potential drug target because it is different from human host and regulates downstream components of redox metabolism of the parasites; essential for their survival, pathogenicity and drug resistance. However, despite the apparent dependency of redox metabolism of cysteine biosynthesis pathway, the role of L. donovani cysteine synthase (LdCS) in drug resistance and redox homeostasis has been unexplored. Herein, we report that over-expression of LdCS in Amphotericin B (Amp B) sensitive strain (S1-OE) modulates resistance towards oxidative stress and drug pressure. We observed that antioxidant enzyme activities were up-regulated in S1-OE parasites and these parasites alleviate intracellular reactive oxygen species (ROS) efficiently by maintaining the reduced thiol pool. In contrast to S1-OE parasites, Amp B sensitive strain (S1) showed higher levels of ROS which was positively correlated with the protein carbonylation levels and negatively correlated with cell viability. Moreover, further investigations showed that LdCS over-expression also augments the ROS-primed induction of LdCS-GFP as well as endogenous LdCS and thiol pathway proteins (LdTryS, LdTryR and LdcTXN) in L. donovani parasites; which probably aids in stress tolerance and drug resistance. In addition, the expression of LdCS was found to be up-regulated in Amp B resistant isolates and during infective stationary stages of growth and consistent with these observations, our ex vivo infectivity studies confirmed that LdCS over-expression enhances the infectivity of L. donovani parasites. Our results reveal a novel crosstalk between LdCS and thiol metabolic pathway proteins and demonstrate the crucial role of LdCS in drug resistance and redox homeostasis of Leishmania. Over-expression of CS in L. donovani modulates oxidative stress & Amp B resistance. Over-expressing parasite possess higher thiol to counteract the oxidative stress. Over-expressing parasites showed increased activity of TXNPx, GST, SOD, and APx. Expression/activity of LdCS is up-regulated in Amp B resistant clinical isolates. Ex vivo results confirm that LdCS over-expression enhance the parasites infectivity. Over-expressing parasites survived long time under oxidative stress conditions.
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Affiliation(s)
- Kuljit Singh
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India; Department of Biotechnology, National Institute of Pharmaceutical Education and Research, EPIP Complex, Hajipur 844102, India
| | - Vahab Ali
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India; Department of Biotechnology, National Institute of Pharmaceutical Education and Research, EPIP Complex, Hajipur 844102, India.
| | - Krishn Pratap Singh
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| | - Parool Gupta
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| | - Shashi S Suman
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| | - Ayan K Ghosh
- Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| | - Sanjiva Bimal
- Department of Immunology, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| | - Krishna Pandey
- Department of Clinical Medicine, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| | - Pradeep Das
- Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
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37
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Singh K, Singh KP, Equbal A, Suman SS, Zaidi A, Garg G, Pandey K, Das P, Ali V. Interaction between cysteine synthase and serine O-acetyltransferase proteins and their stage specific expression in Leishmania donovani. Biochimie 2016; 131:29-44. [PMID: 27638321 DOI: 10.1016/j.biochi.2016.09.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 09/05/2016] [Accepted: 09/05/2016] [Indexed: 01/14/2023]
Abstract
Leishmania possess a unique trypanothione redox metabolism with undebated roles in protection from oxidative damage and drug resistance. The biosynthesis of trypanothione depends on l-cysteine bioavailability which is regulated by cysteine biosynthesis pathway. The de novo cysteine biosynthesis pathway is comprised of serine O-acetyltransferase (SAT) and cysteine synthase (CS) enzymes which sequentially mediate two consecutive steps of cysteine biosynthesis, and is absent in mammalian host. However, despite the apparent dependency of redox metabolism on cysteine biosynthesis pathway, the role of SAT and CS in redox homeostasis has been unexplored in Leishmania parasites. Herein, we have characterized CS and SAT to investigate their interaction and relative abundance of these proteins in promastigote vs. amastigote growth stages of L. donovani. CS and SAT genes of L. donovani (LdCS and LdSAT) were cloned, expressed, and fusion proteins purified to homogeneity with affinity column chromatography. Purified LdCS contains PLP as cofactor and showed optimum enzymatic activity at pH 7.5. Enzyme kinetics showed that LdCS catalyses the synthesis of cysteine using O-acetylserine and sulfide with a Km of 15.86 mM and 0.17 mM, respectively. Digitonin fractionation and indirect immunofluorescence microscopy showed that LdCS and LdSAT are localized in the cytoplasm of promastigotes. Size exclusion chromatography, co-purification, pull down and immuno-precipitation assays demonstrated a stable complex formation between LdCS and LdSAT proteins. Furthermore, LdCS and LdSAT proteins expression/activity was upregulated in amastigote growth stage of the parasite. Thus, the stage specific differential expression of LdCS and LdSAT suggests that it may have a role in the redox homeostasis of Leishmania.
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Affiliation(s)
- Kuljit Singh
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, 800007, India; Department of Biotechnology, National Institute of Pharmaceutical Education and Research, EPIP Complex, Hajipur, 844102, India
| | - Krishn Pratap Singh
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, 800007, India
| | - Asif Equbal
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, 800007, India
| | - Shashi S Suman
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, 800007, India
| | - Amir Zaidi
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, 800007, India
| | - Gaurav Garg
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, 800007, India; Department of Biotechnology, National Institute of Pharmaceutical Education and Research, EPIP Complex, Hajipur, 844102, India
| | - Krishna Pandey
- Department of Clinical Medicine, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, 800007, India
| | - Pradeep Das
- Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, 800007, India
| | - Vahab Ali
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, 800007, India; Department of Biotechnology, National Institute of Pharmaceutical Education and Research, EPIP Complex, Hajipur, 844102, India.
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Role of cysteine residues in the redox-regulated oligomerization and nucleotide binding to EhRabX3. Mol Biochem Parasitol 2016; 208:84-90. [PMID: 27485554 DOI: 10.1016/j.molbiopara.2016.06.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 05/22/2016] [Accepted: 06/28/2016] [Indexed: 11/20/2022]
Abstract
The enteric protozoan parasite, Entamoeba histolytica, an etiological agent of amebiasis, is involved in the adhesion and destruction of human tissues. Worldwide, the parasite causes about 50 million cases of amebiasis and 100,000 deaths annually. EhRabX3, a unique amoebic Rab GTPase with tandem G-domains, possesses an unusually large number of cysteine residues in its N-terminal domain. Crystal structure of EhRabX3 revealed an intra-molecular disulfide bond between C39 and C163 which is critical for maintaining the 3-dimensional architecture and biochemical function of this protein. The remaining six cysteine residues were found to be surface exposed and predicted to be involved in inter-molecular disulfide bonds. In the current study, using biophysical and mutational approaches, we have investigated the role of the cysteine residues in the assembly of EhRabX3 oligomer. The self-association of EhRabX3 is found to be redox sensitive, in vitro. Furthermore, the oligomeric conformation of EhRabX3 failed to bind and exchange the guanine nucleotide, indicating structural re-organization of the active site. Altogether, our results provide valuable insights into the redox-dependent oligomerization of EhRabX3 and its implication on nucleotide binding.
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Chiba Y, Makiuchi T, Jeelani G, Nozaki T. Heterogeneity of the serine synthetic pathway in Entamoeba species. Mol Biochem Parasitol 2016; 207:56-60. [PMID: 27268730 DOI: 10.1016/j.molbiopara.2016.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 11/18/2022]
Abstract
Phosphoserine phosphatase (PSP) catalyzes the third step of the phosphorylated serine biosynthetic pathway, and occurred multiple times in evolution, while enzymes catalyzing the first and second steps in the pathway have single respective origins. In the present study, we examined the existence of PSP among genus Entamoeba including a human enteric parasite, Entamoeba histolytica. E. histolytica as well as majority of Entamoeba species have the first and second enzymes, but lacks PSP. In contrast, a reptilian enteric parasite, Entamoeba invadens possesses canonical PSP. Thus, there are variations in the existence of the serine biosynthetic ability among Entamoeba species.
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Affiliation(s)
- Yoko Chiba
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Takashi Makiuchi
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Ghulam Jeelani
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Tomoyoshi Nozaki
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
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Hanadate Y, Saito-Nakano Y, Nakada-Tsukui K, Nozaki T. Endoplasmic reticulum-resident Rab8A GTPase is involved in phagocytosis in the protozoan parasite Entamoeba histolytica. Cell Microbiol 2016; 18:1358-73. [PMID: 26807810 PMCID: PMC5071775 DOI: 10.1111/cmi.12570] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 12/31/2015] [Accepted: 01/19/2016] [Indexed: 12/20/2022]
Abstract
Phagocytosis is indispensable for the pathogenesis of the intestinal protozoan parasite Entamoeba histolytica. Here, we showed that in E. histolytica Rab8A, which is generally involved in trafficking from the trans‐Golgi network to the plasma membrane in other organisms but was previously identified in phagosomes of the amoeba in the proteomic analysis, primarily resides in the endoplasmic reticulum (ER) and participates in phagocytosis. We demonstrated that down‐regulation of EhRab8A by small antisense RNA‐mediated transcriptional gene silencing remarkably reduced adherence and phagocytosis of erythrocytes, bacteria and carboxylated latex beads. Surface biotinylation followed by SDS‐PAGE analysis revealed that the surface expression of several proteins presumably involved in target recognition was reduced in the EhRab8A gene‐silenced strain. Further, overexpression of wild‐type EhRab8A augmented phagocytosis, whereas expression of the dominant‐negative form of EhRab8A resulted in reduced phagocytosis. These results indicated that EhRab8A regulates transport of surface receptor(s) for the prey from the ER to the plasma membrane. To our knowledge, this is the first report that the ER‐resident Rab GTPase is involved in phagocytosis through the regulation of trafficking of a surface receptor, supporting a premise of direct involvement of the ER in phagocytosis.
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Affiliation(s)
- Yuki Hanadate
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan
| | - Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. .,Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan.
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Pineda E, Vázquez C, Encalada R, Nozaki T, Sato E, Hanadate Y, Néquiz M, Olivos-García A, Moreno-Sánchez R, Saavedra E. Roles of acetyl-CoA synthetase (ADP-forming) and acetate kinase (PPi-forming) in ATP and PPi supply in Entamoeba histolytica. Biochim Biophys Acta Gen Subj 2016; 1860:1163-72. [PMID: 26922831 DOI: 10.1016/j.bbagen.2016.02.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 02/03/2016] [Accepted: 02/21/2016] [Indexed: 10/22/2022]
Abstract
BACKGROUND Acetate is an end-product of the PPi-dependent fermentative glycolysis in Entamoeba histolytica; it is synthesized from acetyl-CoA by ADP-forming acetyl-CoA synthetase (ACS) with net ATP synthesis or from acetyl-phosphate by a unique PPi-forming acetate kinase (AcK). The relevance of these enzymes to the parasite ATP and PPi supply, respectively, are analyzed here. METHODS The recombinant enzymes were kinetically characterized and their physiological roles were analyzed by transcriptional gene silencing and further metabolic analyses in amoebae. RESULTS Recombinant ACS showed higher catalytic efficiencies (Vmax/Km) for acetate formation than for acetyl-CoA formation and high acetyl-CoA levels were found in trophozoites. Gradual ACS gene silencing (49-93%) significantly decreased the acetate flux without affecting the levels of glycolytic metabolites and ATP in trophozoites. However, amoebae lacking ACS activity were unable to reestablish the acetyl-CoA/CoA ratio after an oxidative stress challenge. Recombinant AcK showed activity only in the acetate formation direction; however, its substrate acetyl-phosphate was undetected in axenic parasites. AcK gene silencing did not affect acetate production in the parasites but promoted a slight decrease (10-20%) in the hexose phosphates and PPi levels. CONCLUSIONS These results indicated that the main role of ACS in the parasite energy metabolism is not ATP production but to recycle CoA for glycolysis to proceed under aerobic conditions. AcK does not contribute to acetate production but might be marginally involved in PPi and hexosephosphate homeostasis. SIGNIFICANCE The previous, long-standing hypothesis that these enzymes importantly contribute to ATP and PPi supply in amoebae can now be ruled out.
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Affiliation(s)
- Erika Pineda
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez. Mexico D.F. 14080, Mexico
| | - Citlali Vázquez
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez. Mexico D.F. 14080, Mexico
| | - Rusely Encalada
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez. Mexico D.F. 14080, Mexico
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious Diseases. Tokyo 162-8640, Japan
| | - Emi Sato
- Department of Parasitology, National Institute of Infectious Diseases. Tokyo 162-8640, Japan
| | - Yuki Hanadate
- Department of Parasitology, National Institute of Infectious Diseases. Tokyo 162-8640, Japan
| | - Mario Néquiz
- Departamento de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México. Mexico D.F. 04510, Mexico
| | - Alfonso Olivos-García
- Departamento de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México. Mexico D.F. 04510, Mexico
| | - Rafael Moreno-Sánchez
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez. Mexico D.F. 14080, Mexico
| | - Emma Saavedra
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez. Mexico D.F. 14080, Mexico.
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42
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Srivastava VK, Chandra M, Saito-Nakano Y, Nozaki T, Datta S. Crystal Structure Analysis of Wild Type and Fast Hydrolyzing Mutant of EhRabX3, a Tandem Ras Superfamily GTPase from Entamoeba histolytica. J Mol Biol 2015; 428:41-51. [PMID: 26555751 DOI: 10.1016/j.jmb.2015.11.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 10/30/2015] [Accepted: 11/04/2015] [Indexed: 10/22/2022]
Abstract
The enteric protozoan parasite, Entamoeba histolytica, is the causative agent of amoebic dysentery, liver abscess and colitis in human. Vesicular trafficking plays a key role in the survival and virulence of the protozoan and is regulated by various Rab GTPases. EhRabX3 is a catalytically inefficient amoebic Rab protein, which is unique among the eukaryotic Ras superfamily by virtue of its tandem domain organization. Here, we report the crystal structures of GDP-bound fast hydrolyzing mutant (V71A/K73Q) and GTP-bound wild type EhRabX3 at 3.1 and 2.8Å resolutions, respectively. Though both G-domains possess "phosphate binding loop containing nucleoside triphosphate hydrolases fold", only the N-terminal domain binds to guanine nucleotide. The relative orientation of the N-terminal domain and C-terminal domain is stabilized by numerous inter-domain interactions. Compared to other Ras superfamily members, both the GTPase domains displayed large deviation in switch II perhaps due to non-conservative substitutions in this region. As a result, entire switch II is restructured and moved away from the nucleotide binding pocket, providing a rationale for the diminished GTPase activity of EhRabX3. The N-terminal GTPase domain possesses unusually large number of cysteine residues. X-ray crystal structure of the fast hydrolyzing mutant of EhRabX3 revealed that C39 and C163 formed an intra-molecular disulfide bond. Subsequent mutational and biochemical studies suggest that C39 and C163 are critical for maintaining the structural integrity and function of EhRabX3. Structure-guided functional investigation of cysteine mutants could provide the physiological implications of the disulfide bond and could allow us to design potential inhibitors for the better treatment of intestinal amebiasis.
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Affiliation(s)
- Vijay Kumar Srivastava
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal 462023, India
| | - Mintu Chandra
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal 462023, India
| | - Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases Shinjuku-ku, Tokyo 162-8640, Japan
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious Diseases Shinjuku-ku, Tokyo 162-8640, Japan
| | - Sunando Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal 462023, India,.
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43
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Azam A, Peerzada MN, Ahmad K. Parasitic diarrheal disease: drug development and targets. Front Microbiol 2015; 6:1183. [PMID: 26617574 PMCID: PMC4621754 DOI: 10.3389/fmicb.2015.01183] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 10/12/2015] [Indexed: 12/23/2022] Open
Abstract
Diarrhea is the manifestation of gastrointestinal infection and is one of the major causes of mortality and morbidity specifically among the children of less than 5 years age worldwide. Moreover, in recent years there has been a rise in the number of reports of intestinal infections continuously in the industrialized world. These are largely related to waterborne and food borne outbreaks. These occur by the pathogenesis of both prokaryotic and eukaryotic organisms like bacteria and parasites. The parasitic intestinal infection has remained mostly unexplored and under assessed in terms of therapeutic development. The lack of new drugs and the risk of resistance have led us to carry out this review on drug development for parasitic diarrheal diseases. The major focus has been depicted on commercially available drugs, currently synthesized active heterocyclic compounds and unique drug targets, that are vital for the existence and growth of the parasites and can be further exploited for the search of therapeutically active anti-parasitic agents.
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Affiliation(s)
- Amir Azam
- Medicinal Chemistry Laboratory, Department of Chemistry, Jamia Millia IslamiaNew Delhi, India
| | - Mudasir N. Peerzada
- Medicinal Chemistry Laboratory, Department of Chemistry, Jamia Millia IslamiaNew Delhi, India
| | - Kamal Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia IslamiaNew Delhi, India
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44
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Andrade RM, Reed SL. New drug target in protozoan parasites: the role of thioredoxin reductase. Front Microbiol 2015; 6:975. [PMID: 26483758 PMCID: PMC4588103 DOI: 10.3389/fmicb.2015.00975] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/02/2015] [Indexed: 01/04/2023] Open
Abstract
Amebiasis causes approximately 70,000 deaths annually and is the third cause of death due to parasites worldwide. It is treated primarily with metronidazole, which has adverse side effects, is mutagenic and carcinogenic, and emergence of resistance is an increasing concern. Unfortunately, better therapeutic alternatives are lacking. Re-purposing of older FDA approved drugs is advantageous to drug discovery since safety and pharmacokinetic effects in humans are already known. In high throughput screening studies, we recently demonstrated that auranofin, a gold containing compound originally approved to treat rheumatoid arthritis, has activity against trophozoites of E. histolytica, the causative agent of amebiasis. Auranofin's anti-parasitic activity is attributed to its monovalent gold molecule that readily inhibits E. histolytica thioredoxin reductase. This anti-oxidant enzyme is the only thiol-dependent flavo-reductase present in E. histolytica. Auranofin has also shown promising activity against other protozoans of significant public health importance. Altogether, this evidence suggests that auranofin has the potential to become a broad spectrum alternative therapeutic agent for diseases with a large global burden.
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Affiliation(s)
- Rosa M Andrade
- Division of Infectious Diseases, Department of Medicine, University of California San Diego La Jolla, CA, USA
| | - Sharon L Reed
- Division of Infectious Diseases, Department of Pathology, School of Medicine, University of California San Diego La Jolla, CA, USA
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45
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Mori M, Jeelani G, Masuda Y, Sakai K, Tsukui K, Waluyo D, Tarwadi, Watanabe Y, Nonaka K, Matsumoto A, Ōmura S, Nozaki T, Shiomi K. Identification of natural inhibitors of Entamoeba histolytica cysteine synthase from microbial secondary metabolites. Front Microbiol 2015; 6:962. [PMID: 26441896 PMCID: PMC4568418 DOI: 10.3389/fmicb.2015.00962] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 08/31/2015] [Indexed: 11/13/2022] Open
Abstract
Amebiasis is a common worldwide diarrheal disease, caused by the protozoan parasite, Entamoeba histolytica. Metronidazole has been a drug of choice against amebiasis for decades despite its known side effects and low efficacy against asymptomatic cyst carriers. E. histolytica is also capable of surviving sub-therapeutic levels of metronidazole in vitro. Novel drugs with different mode of action are therefore urgently needed. The sulfur assimilatory de novo L-cysteine biosynthetic pathway is essential for various cellular activities, including the proliferation and anti-oxidative defense of E. histolytica. Since the pathway, consisting of two reactions catalyzed by serine acetyltransferase (SAT) and cysteine synthase (CS, O-acetylserine sulfhydrylase), does not exist in humans, it is a rational drug target against amebiasis. To discover inhibitors against the CS of E. histolytica (EhCS), the compounds of Kitasato Natural Products Library were screened against two recombinant CS isozymes: EhCS1 and EhCS3. Nine compounds inhibited EhCS1 and EhCS3 with IC50 values of 0.31-490 μM. Of those, seven compounds share a naphthoquinone moiety, indicating the structural importance of the moiety for binding to the active site of EhCS1 and EhCS3. We further screened >9,000 microbial broths for CS inhibition and purified two compounds, xanthofulvin and exophillic acid from fungal broths. Xanthofulvin inhibited EhCS1 and EhCS3. Exophillic acid showed high selectivity against EhCS1, but exhibited no inhibition against EhCS3. In vitro anti-amebic activity of the 11 EhCS inhibitors was also examined. Deacetylkinamycin C and nanaomycin A showed more potent amebicidal activity with IC50 values of 18 and 0.8 μM, respectively, in the cysteine deprived conditions. The differential sensitivity of trophozoites against deacetylkinamycin C in the presence or absence of L-cysteine in the medium and the IC50 values against EhCS suggest the amebicidal effect of deacetylkinamycin C is due to CS inhibition.
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Affiliation(s)
- Mihoko Mori
- Kitasato Institute for Life Sciences, Kitasato UniversityTokyo, Japan
- Graduate School of Infection Control Sciences, Kitasato UniversityTokyo, Japan
| | - Ghulam Jeelani
- Department of Parasitology, National Institute of Infectious DiseasesTokyo, Japan
| | - Yui Masuda
- Graduate School of Infection Control Sciences, Kitasato UniversityTokyo, Japan
| | - Kazunari Sakai
- Graduate School of Infection Control Sciences, Kitasato UniversityTokyo, Japan
| | - Kumiko Tsukui
- Department of Parasitology, National Institute of Infectious DiseasesTokyo, Japan
| | - Danang Waluyo
- Biotech Center, Badan Pengkajian Dan Penerapan TeknologiBanten, Indonesia
| | - Tarwadi
- Biotech Center, Badan Pengkajian Dan Penerapan TeknologiBanten, Indonesia
| | - Yoshio Watanabe
- Research and Development Division, MicroBiopharm Japan Co. LtdIwata, Japan
| | - Kenichi Nonaka
- Kitasato Institute for Life Sciences, Kitasato UniversityTokyo, Japan
- Graduate School of Infection Control Sciences, Kitasato UniversityTokyo, Japan
| | - Atsuko Matsumoto
- Kitasato Institute for Life Sciences, Kitasato UniversityTokyo, Japan
- Graduate School of Infection Control Sciences, Kitasato UniversityTokyo, Japan
| | - Satoshi Ōmura
- Kitasato Institute for Life Sciences, Kitasato UniversityTokyo, Japan
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious DiseasesTokyo, Japan
- Graduate School of Life and Environmental Sciences, University of TsukubaTsukuba, Japan
| | - Kazuro Shiomi
- Kitasato Institute for Life Sciences, Kitasato UniversityTokyo, Japan
- Graduate School of Infection Control Sciences, Kitasato UniversityTokyo, Japan
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46
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Chiba Y, Kamikawa R, Nakada-Tsukui K, Saito-Nakano Y, Nozaki T. Discovery of PPi-type Phosphoenolpyruvate Carboxykinase Genes in Eukaryotes and Bacteria. J Biol Chem 2015; 290:23960-70. [PMID: 26269598 DOI: 10.1074/jbc.m115.672907] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Indexed: 01/15/2023] Open
Abstract
Phosphoenolpyruvate carboxykinase (PEPCK) is one of the pivotal enzymes that regulates the carbon flow of the central metabolism by fixing CO2 to phosphoenolpyruvate (PEP) to produce oxaloacetate or vice versa. Whereas ATP- and GTP-type PEPCKs have been well studied, and their protein identities are established, inorganic pyrophosphate (PPi)-type PEPCK (PPi-PEPCK) is poorly characterized. Despite extensive enzymological studies, its protein identity and encoding gene remain unknown. In this study, PPi-PEPCK has been identified for the first time from a eukaryotic human parasite, Entamoeba histolytica, by conventional purification and mass spectrometric identification of the native enzyme, followed by demonstration of its enzymatic activity. A homolog of the amebic PPi-PEPCK from an anaerobic bacterium Propionibacterium freudenreichii subsp. shermanii also exhibited PPi-PEPCK activity. The primary structure of PPi-PEPCK has no similarity to the functional homologs ATP/GTP-PEPCKs and PEP carboxylase, strongly suggesting that PPi-PEPCK arose independently from the other functional homologues and very likely has unique catalytic sites. PPi-PEPCK homologs were found in a variety of bacteria and some eukaryotes but not in archaea. The molecular identification of this long forgotten enzyme shows us the diversity and functional redundancy of enzymes involved in the central metabolism and can help us to understand the central metabolism more deeply.
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Affiliation(s)
- Yoko Chiba
- From the Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan, the Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan, and
| | - Ryoma Kamikawa
- the Graduate School of Environmental Studies, Graduate School of Human and Environmental Studies, Kyoto University, Yoshida Nihonmatsu cho, Kyoto, Kyoto 606-8501, Japan
| | - Kumiko Nakada-Tsukui
- the Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan, and
| | - Yumiko Saito-Nakano
- the Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan, and
| | - Tomoyoshi Nozaki
- From the Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan, the Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan, and
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47
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Picazarri K, Nakada-Tsukui K, Tsuboi K, Miyamoto E, Watanabe N, Kawakami E, Nozaki T. Atg8 is involved in endosomal and phagosomal acidification in the parasitic protist Entamoeba histolytica. Cell Microbiol 2015; 17:1510-22. [PMID: 25923949 PMCID: PMC4744732 DOI: 10.1111/cmi.12453] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 04/09/2015] [Accepted: 04/23/2015] [Indexed: 01/08/2023]
Abstract
Autophagy is one of two major bulk protein degradation systems and is conserved throughout eukaryotes. The protozoan Entamoeba histolytica, which is a human intestinal parasite, possesses a restricted set of autophagy‐related (Atg) proteins compared with other eukaryotes and thus represents a suitable model organism for studying the minimal essential components and ancestral functions of autophagy. E. histolytica possesses two conjugation systems: Atg8 and Atg5/12, although a gene encoding Atg12 is missing in the genome. Atg8 is considered to be the central and authentic marker of autophagosomes, but recent studies have demonstrated that Atg8 is not exclusively involved in autophagy per se, but other fundamental mechanisms of vesicular traffic. To investigate this question in E. histolytica, we studied on Atg8 during the proliferative stage. Atg8 was constitutively expressed in both laboratory‐maintained and recently established clinical isolates and appeared to be lipid‐modified in logarithmic growth phase, suggesting a role of Atg8 in non‐stress and proliferative conditions. These findings are in contrast to those for Entamoeba invadens, in which autophagy is markedly induced during an early phase of differentiation from the trophozoite into the cyst. The repression of Atg8 gene expression in En. histolytica by antisense small RNA‐mediated transcriptional gene silencing resulted in growth retardation, delayed endocytosis and reduced acidification of endosomes and phagosomes. Taken together, these results suggest that Atg8 and the Atg8 conjugation pathway have some roles in the biogenesis of endosomes and phagosomes in this primitive eukaryote.
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Affiliation(s)
- Karina Picazarri
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kumiko Tsuboi
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Eri Miyamoto
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Department of Biomolecular Science, Faculty of Science, Toho University, Chiba, Japan
| | - Naoko Watanabe
- Department of Biomolecular Science, Faculty of Science, Toho University, Chiba, Japan
| | - Eiryo Kawakami
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Laboratory for Disease Systems Modeling, RIKEN Center for integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, Japan
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
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48
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Upregulation of Cysteine Synthase and Cystathionine β-Synthase Contributes to Leishmania braziliensis Survival under Oxidative Stress. Antimicrob Agents Chemother 2015; 59:4770-81. [PMID: 26033728 DOI: 10.1128/aac.04880-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 05/14/2015] [Indexed: 12/19/2022] Open
Abstract
Cysteine metabolism is considered essential for the crucial maintenance of a reducing environment in trypanosomatids due to its importance as a precursor of trypanothione biosynthesis. Expression, activity, functional rescue, and overexpression of cysteine synthase (CS) and cystathionine β-synthase (CβS) were evaluated in Leishmania braziliensis promastigotes and intracellular amastigotes under in vitro stress conditions induced by hydrogen peroxide (H2O2), S-nitroso-N-acetylpenicillamine, or antimonial compounds. Our results demonstrate a stage-specific increase in the levels of protein expression and activity of L. braziliensis CS (LbrCS) and L. braziliensis CβS (LbrCβS), resulting in an increment of total thiol levels in response to both oxidative and nitrosative stress. The rescue of the CS activity in Trypanosoma rangeli, a trypanosome that does not perform cysteine biosynthesis de novo, resulted in increased rates of survival of epimastigotes expressing the LbrCS under stress conditions compared to those of wild-type parasites. We also found that the ability of L. braziliensis promastigotes and amastigotes overexpressing LbrCS and LbrCβS to resist oxidative stress was significantly enhanced compared to that of nontransfected cells, resulting in a phenotype far more resistant to treatment with the pentavalent form of Sb in vitro. In conclusion, the upregulation of protein expression and increment of the levels of LbrCS and LbrCβS activity alter parasite resistance to antimonials and may influence the efficacy of antimony treatment of New World leishmaniasis.
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49
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Santos F, Nequiz M, Hernández-Cuevas NA, Hernández K, Pineda E, Encalada R, Guillén N, Luis-García E, Saralegui A, Saavedra E, Pérez-Tamayo R, Olivos-García A. Maintenance of intracellular hypoxia and adequate heat shock response are essential requirements for pathogenicity and virulence ofEntamoeba histolytica. Cell Microbiol 2015; 17:1037-51. [DOI: 10.1111/cmi.12419] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 01/05/2015] [Accepted: 01/16/2015] [Indexed: 01/16/2023]
Affiliation(s)
- Fabiola Santos
- Departamento de Medicina Experimental, Facultad de Medicina; Universidad Nacional Autónoma de México; Mexico D.F. 04510 Mexico
- Escuela Nacional de Ciencias Biológicas; Instituto Politécnico Nacional; México D.F. 11340 Mexico
| | - Mario Nequiz
- Departamento de Medicina Experimental, Facultad de Medicina; Universidad Nacional Autónoma de México; Mexico D.F. 04510 Mexico
| | | | - Kahory Hernández
- Departamento de Medicina Experimental, Facultad de Medicina; Universidad Nacional Autónoma de México; Mexico D.F. 04510 Mexico
| | - Erika Pineda
- Departamento de Bioquímica; Instituto Nacional de Cardiología Ignacio Chávez; Mexico D.F. 14080 Mexico
| | - Rusely Encalada
- Departamento de Bioquímica; Instituto Nacional de Cardiología Ignacio Chávez; Mexico D.F. 14080 Mexico
| | - Nancy Guillén
- Unité Biologie Cellulaire du Parasitisme; Institut Pasteur; Paris F-75015 France
- INSERM, U786; Paris F-75015 France
| | - Erika Luis-García
- Departamento de Medicina Experimental, Facultad de Medicina; Universidad Nacional Autónoma de México; Mexico D.F. 04510 Mexico
| | - Andrés Saralegui
- Laboratorio Nacional de Microscopía Avanzada, Instituto de Biotecnología; Universidad Nacional Autónoma de México; Cuernavaca Morelos 62250 Mexico
| | - Emma Saavedra
- Departamento de Bioquímica; Instituto Nacional de Cardiología Ignacio Chávez; Mexico D.F. 14080 Mexico
| | - Ruy Pérez-Tamayo
- Departamento de Medicina Experimental, Facultad de Medicina; Universidad Nacional Autónoma de México; Mexico D.F. 04510 Mexico
| | - Alfonso Olivos-García
- Departamento de Medicina Experimental, Facultad de Medicina; Universidad Nacional Autónoma de México; Mexico D.F. 04510 Mexico
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50
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Lee YA, Saito-Nakano Y, Kim KA, Min A, Nozaki T, Shin MH. Modulation of endogenous Cysteine Protease Inhibitor (ICP) 1 expression in Entamoeba histolytica affects amoebic adhesion to Extracellular Matrix proteins. Exp Parasitol 2014; 149:7-15. [PMID: 25500214 DOI: 10.1016/j.exppara.2014.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 11/07/2014] [Accepted: 12/02/2014] [Indexed: 12/31/2022]
Abstract
Entamoeba histolytica is an enteric tissue-invading protozoan parasite that causes amoebic colitis and occasionally liver abscess in humans. During tissue invasion, amoebic adhesion to host components is an important event for host cell death leading to successful invasion and infection. Among amoebic virulence factors, Gal/GalNAc lectin is known to be major adhesion factor to host cells. In this study, we investigated the role of amoebic secreted CP (Cysteine Proteases) in amoebic adhesion to extracellular matrix (ECM) protein using CP inhibitor and E. histolytica strains in which the endogenous inhibitor of cysteine protease (ICP) 1 gene was overexpressed (ICP1(+)) or repressed by antisense small RNA-mediated gene silencing (ICP1(-)). We found that pretreatment of wild-type amoebae with CP inhibitor E64, or thiol-group modifiers such as diamide and N-Ethylmaleimide resulted in a significant decrease in adhesion to laminin and collagen ECM proteins. Furthermore, ICP1(+) strain, with a reduction of secreted CP activity, exhibited reduced ability by 40% to adhere to laminin. In contrast, ICP1(-) strain, with a 1.9-fold increase of secreted CP activity, showed a two-fold increase in amoebic adherence to laminin compared to the control strain. In addition, total amount of secreted CP5 was decreased in ICP1(+) amoeba. Conversely, total amount of secreted CP1 and mature-form CP5 were increased in ICP1(-) amoeba. We also found that ICP1 was secreted into extracellular milieu. These results suggest that secreted CP activity by E. histolytica may be an important factor affecting adhesion to host proteins, and regulation of CP secretion by ICP plays a major role in pathogenesis. This study provides insight into the CP-mediated tissue pathogenesis in amoeba-invaded lesions during human amoebiasis.
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Affiliation(s)
- Young Ah Lee
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan
| | - Kyeong Ah Kim
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Arim Min
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan
| | - Myeong Heon Shin
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea.
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