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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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Kumari P, Agrawal P, Umarao P, Ramachandran V, Gourinath S. Identification of Small Molecule Inhibitors Targeting Phosphoserine Phosphatase: A Novel Target for the Development of Antiamoebic Drugs. ACS OMEGA 2024; 9:27906-27918. [PMID: 38973836 PMCID: PMC11223228 DOI: 10.1021/acsomega.3c09439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/25/2024] [Accepted: 01/31/2024] [Indexed: 07/09/2024]
Abstract
Amoebiasis, a widespread disease caused by the protozoan parasite Entamoeba histolytica, poses challenges due to the adverse effects of existing antiamoebic drugs and rising drug resistance. Novel targeted drugs are in need of the hour to combat the prevalence of this disease. Given the significance of cysteine for Entamoeba survival, the rate-determining step in the serine (the sole substrate of cysteine synthesis) biosynthetic pathway, i.e., the conversion of 3-phosphoserine to l-serine catalyzed by phosphoserine phosphatase (PSP), emerges as a promising drug target. Our previous study unveils the essential role of EhPSP in amoebas' survival, particularly under oxidative stress, by increasing cysteine production. The study also revealed that EhPSP differs significantly from its human counterpart, both structurally and biochemically, highlighting its potential as a viable target for developing new antiamoebic drugs. In the present study, employing in silico screening of vast natural and synthetic small chemical compound libraries, we identified 21 potential EhPSP inhibitor molecules. Out of the 21 compounds examined, only five could inhibit the catalytic activity of EhPSP. The inhibition capability of these five compounds was subsequently validated by in silico binding free energy calculations, SPR-based real-time binding studies, and molecular simulations to assess the stability of the EhPSP-inhibitor complexes. By identifying the five potential inhibitors that can target cysteine synthesis via EhPSP, our findings establish EhPSP as a drug candidate that can serve as a foundation for antiamoebic drug research.
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Affiliation(s)
- Poonam Kumari
- International
Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
- Structural
Biology Lab, School of Life Sciences, Jawaharlal
Nehru University, New Delhi 110067, India
| | - Prakhar Agrawal
- International
Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Preeti Umarao
- Structural
Biology Lab, School of Life Sciences, Jawaharlal
Nehru University, New Delhi 110067, India
| | - Vijayan Ramachandran
- The
Centre for Innovation in Brain Sciences, University of Arizona, Tucson 85721, Arizona, United States
| | - Samudrala Gourinath
- Structural
Biology Lab, School of Life Sciences, Jawaharlal
Nehru University, New Delhi 110067, India
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Nawaz A, Priya B, Singh K, Ali V. Unveiling the role of serine o-acetyltransferase in drug resistance and oxidative stress tolerance in Leishmania donovani through the regulation of thiol-based redox metabolism. Free Radic Biol Med 2024; 213:371-393. [PMID: 38272324 DOI: 10.1016/j.freeradbiomed.2024.01.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 12/25/2023] [Accepted: 01/22/2024] [Indexed: 01/27/2024]
Abstract
Understanding the unique metabolic pathway of L. donovani is crucial for comprehending its biology under oxidative stress conditions. The de novo cysteine biosynthetic pathway of L. donovani is absent in humans and its product, cysteine regulates the downstream components of trypanothione-based thiol metabolism, important for maintaining cellular redox homeostasis. The role of serine o-acetyl transferase (SAT), the first enzyme of this pathway remains unexplored. In order to investigate the role of SAT protein, we cloned SAT gene into pXG-GFP+ vector for episomal expression of SAT in Amphotericin B sensitive L. donovani promastigotes. The SAT overexpression was confirmed by SAT enzymatic assay, GFP fluorescence, immunoblotting and PCR. Our study unveiled an upregulated expression of both LdSAT and LdCS of cysteine biosynthetic pathway and other downstream thiol pathway proteins in LdSAT-OE promastigotes. Additionally, there was an increase in enzymatic activities of LdSAT and LdCS proteins in LdSAT-OE, which was found similar to the Amp B resistant parasites, indicating a potential role of SAT protein in modulating drug resistance. We observed that the overexpression of SAT in Amp B sensitive parasites increases tolerance to drug pressure and oxidative stress via trypanothione-dependent antioxidant mechanism. Moreover, the in vitro J774A.1 macrophage infectivity assessment showed that SAT overexpression augments parasite infectivity. In LdSAT-OE promastigotes, antioxidant enzyme activities like APx and SOD were upregulated, intracellular reactive oxygen species were reduced with a corresponding increase in thiol level, emphasizing SAT's role in stress tolerance and enhanced infectivity. Additionally, the ROS mediated upregulation in the expression of LdSAT, LdCS, LdTryS and LdcTXNPx proteins reveals an essential cross talk between SAT and proteins of thiol metabolism in combating oxidative stress and maintaining redox homeostasis. Taken together, our results provide the first insight into the role of SAT protein in parasite infectivity and survival under drug pressure and oxidative stress.
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Affiliation(s)
- Afreen Nawaz
- ICMR - Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, 800007, India
| | - Bhawna Priya
- ICMR - Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, 800007, India
| | - Kuljit Singh
- Infectious Diseases Division, CSIR - Indian Institute of Integrative Medicine, Jammu, 180001, India
| | - Vahab Ali
- ICMR - Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, 800007, India.
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4
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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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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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Dharavath S, Kumari K, Kumar S, Gourinath S. Structural and functional studies of serine acetyltransferase isoform from Entamoeba histolytica reveals novel role of the C-terminal tail in loss of regulation from feedback inhibition. Int J Biol Macromol 2022; 217:689-700. [PMID: 35853506 DOI: 10.1016/j.ijbiomac.2022.07.095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/28/2022] [Accepted: 07/12/2022] [Indexed: 11/19/2022]
Abstract
Serine acetyltransferase (SAT) catalyzes the acetylation of l-serine in the first step of the two-step pathway to synthesize L-cysteine in bacteria, protozoans and plants. L-cysteine is known to be involved in feedback regulation of SAT. However, in E. histolytica, SAT exists in three isoforms where third isoform SAT3 is nearly insensitive to feedback inhibition. Here, we explored the previously unknown precise mechanism of the insensitivity of EhSAT3 to L-cysteine. The C-terminal deletion mutants of EhSAT3 were inhibited completely by L-cysteine in contrast to the wildtype EhSAT3. The crystal structure of EhSAT3ΔC22 in complex with cysteine revealed that C-terminal region swaps over the neighboring monomer in the trimer. This structure combined with the modeled C-terminal residues suggests that EhSAT3 C-terminal end interacts with the active site and play crucial role in feedback inhibition. The interacting distances between sulfur of cysteine and protein indicate cysteine is in deprotonated (S-) state, thus making stronger interactions than serine. In the full length SAT3, C-terminal tail provides an acidic environment at the active site pocket, so that cysteine can't be deprotonated and bind strongly at the active site. These results conveyed a unique role of the C-terminal region of EhSAT3 in regulating the feedback inhibition.
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Affiliation(s)
| | - Khushboo Kumari
- School of Life sciences, Jawaharlal Nehru University, New Delhi, India
| | - Sudhir Kumar
- Department of Biotechnology, H.N.B. Garhwal University, Srinagar Garhwal, Uttarakhand, India.
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Ali V, Behera S, Nawaz A, Equbal A, Pandey K. Unique thiol metabolism in trypanosomatids: Redox homeostasis and drug resistance. ADVANCES IN PARASITOLOGY 2022; 117:75-155. [PMID: 35878950 DOI: 10.1016/bs.apar.2022.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Trypanosomatids are mainly responsible for heterogeneous parasitic diseases: Leishmaniasis, Sleeping sickness, and Chagas disease and control of these diseases implicates serious challenges due to the emergence of drug resistance. Redox-active biomolecules are the endogenous substances in organisms, which play important role in the regulation of redox homeostasis. The redox-active substances like glutathione, trypanothione, cysteine, cysteine persulfides, etc., and other inorganic intermediates (hydrogen peroxide, nitric oxide) are very useful as defence mechanism. In the present review, the suitability of trypanothione and other essential thiol molecules of trypanosomatids as drug targets are described in Leishmania and Trypanosoma. We have explored the role of tryparedoxin, tryparedoxin peroxidase, ascorbate peroxidase, superoxide dismutase, and glutaredoxins in the anti-oxidant mechanism and drug resistance. Up-regulation of some proteins in trypanothione metabolism helps the parasites in survival against drug pressure (sodium stibogluconate, Amphotericin B, etc.) and oxidative stress. These molecules accept electrons from the reduced trypanothione and donate their electrons to other proteins, and these proteins reduce toxic molecules, neutralize reactive oxygen, or nitrogen species; and help parasites to cope with oxidative stress. Thus, a better understanding of the role of these molecules in drug resistance and redox homeostasis will help to target metabolic pathway proteins to combat Leishmaniasis and trypanosomiases.
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Affiliation(s)
- Vahab Ali
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India.
| | - Sachidananda Behera
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India
| | - Afreen Nawaz
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India
| | - Asif Equbal
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India; Department of Botany, Araria College, Purnea University, Purnia, Bihar, India
| | - Krishna Pandey
- Department of Clinical Medicine, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India
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Nugraha RYB, Jeelani G, Nozaki T. Physiological roles and metabolism of γ-aminobutyric acid (GABA) in parasitic protozoa. Trends Parasitol 2022; 38:462-477. [DOI: 10.1016/j.pt.2022.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/20/2022] [Accepted: 02/04/2022] [Indexed: 11/16/2022]
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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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Saxena VK, Vedamurthy GV, Swarnkar CP, Kadam V, Onteru SK, Ahmad H, Singh R. De novo pathway is an active metabolic pathway of cysteine synthesis in Haemonchus contortus. Biochimie 2021; 187:110-120. [PMID: 34082042 DOI: 10.1016/j.biochi.2021.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/19/2021] [Accepted: 05/25/2021] [Indexed: 01/25/2023]
Abstract
Haemonchus contortus, commonly known as Barber's pole worm, is an economically important gastrointestinal nematode of sheep and goats especially in tropical and sub-tropical regions of the world. Cysteine synthesis is a very important metabolic pathway for the parasite, however the functional aspects of cysteine synthesis in parasite are largely unknown. The key question which we have investigated in the study is; whether the parasite uses a de novo pathway of cysteine synthesis, which is unknown in multicellular organisms of the animal kingdom and known to be absent in mammals. Directional cloning of the cysteine synthase (CS) gene was done in pET303 champion vector using restriction sites XbaI and XhoI. The CS gene of the H.contortus was closely related to CS-A protein of Oesophagostomum dentatum and a hypothetical protein of Ancylostoma ceylanicum. Recombinant protein of the H contortus CS (rHC-CS) gene was expressed using pET303 vector in pLysS BL21 strain of E.coli and subsequently purified by Ni-NTA affinity chromatography. Western blot using anti-His tag antibody confirmed the presence of rHC-CS. Biochemical assay, FTIR and enzyme kinetics studies revealed that rHC-CS used O-acetyl serine as substrate to produce cysteine using de novo pathway and CS activity was also confirmed with the homogenate of H.contortus. Upregulation of CS transcripts in the adult and its downregulation in the L3 larval stage suggests that de novo pathway contributes to the cysteine requirement of mature H.contortus. It is concluded that de novo pathway is an active metabolic pathway in H.contortus.
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Affiliation(s)
- Vijay Kumar Saxena
- Molecular Physiology Laboratory, Division of Physiology and Biochemistry, Central Sheep and Wool Research Institute, ICAR-CSWRI, Avikanagar, Rajasthan, 304501, India.
| | - G V Vedamurthy
- Livestock Research Centre, Southren Regional Station, National Dairy Research Institute, ICAR-NDRI (SRS), Bengaluru, Karnataka, 560030, India
| | - C P Swarnkar
- Animal Health Division, Central Sheep and Wool Research Institute, ICAR-CSWRI, Avikanagar, Rajasthan, 304501, India
| | - Vinod Kadam
- Textile Manufacturing and Textile Chemistry Division, ICAR- Central Sheep and Wool Research Institute, Avikanagar, Rajasthan, 304501, India
| | - Suneel Kumar Onteru
- Animal Biochemistry Division, National Dairy Research Institute, ICAR-NDRI, Karnal, Haryana, 132001, India
| | - Haseen Ahmad
- Animal Biochemistry Division, National Dairy Research Institute, ICAR-NDRI, Karnal, Haryana, 132001, India
| | - Raghvendar Singh
- Molecular Physiology Laboratory, Division of Physiology and Biochemistry, Central Sheep and Wool Research Institute, ICAR-CSWRI, Avikanagar, Rajasthan, 304501, India
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Das K, Watanabe N, Nozaki T. Two StAR-related lipid transfer proteins play specific roles in endocytosis, exocytosis, and motility in the parasitic protist Entamoeba histolytica. PLoS Pathog 2021; 17:e1009551. [PMID: 33909710 PMCID: PMC8109825 DOI: 10.1371/journal.ppat.1009551] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 05/10/2021] [Accepted: 04/09/2021] [Indexed: 12/26/2022] Open
Abstract
Lipid transfer proteins (LTPs) are the key contributor of organelle-specific lipid distribution and cellular lipid homeostasis. Here, we report a novel implication of LTPs in phagocytosis, trogocytosis, pinocytosis, biosynthetic secretion, recycling of pinosomes, and motility of the parasitic protist E. histolytica, the etiological agent of human amoebiasis. We show that two StAR-related lipid transfer (START) domain-containing LTPs (named as EhLTP1 and 3) are involved in these biological pathways in an LTP-specific manner. Our findings provide novel implications of LTPs, which are relevant to the elucidation of pathophysiology of the diseases caused by parasitic protists. We showed that EhLTP1, but not EhLTP3, is involved in secretion of cysteine protease, the well-established degrading factor of host cells and the extracellular matrix, and in pseudopod formation and migration. In contrast, EhLTP3, but not EhLTP1, is exclusively involved in pinocytosis of the fluid-phase marker. Both EhLTP1 and EhLTP3 are also involved in trogocytosis (ingestion by nibbling) of live mammalian cells and phagocytosis of dead cells. In trogocytosis and phagcytosis, these two LTPs displayed distinct patterns of recruitment: e.g., EhLTP1 was associated at the ligand attachment site at the initiation of trogocytosis, followed by the recruitment of EhLTP3 onto the “trogocytic tunnel” at the intermediate stage of trogocytosis before the closure of the trogosome. Such tempo-spatially coordinated involvement of LTPs in the course of trogo- and phagocytosis has never been demonstrated in unicellular eukaryotes. Neither has LTP been shown to be involved in both endocytosis and exocytosis.
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Affiliation(s)
- Koushik Das
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Natsuki Watanabe
- 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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Shrivastav MT, Malik Z, Somlata. Revisiting Drug Development Against the Neglected Tropical Disease, Amebiasis. Front Cell Infect Microbiol 2021; 10:628257. [PMID: 33718258 PMCID: PMC7943716 DOI: 10.3389/fcimb.2020.628257] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 12/30/2020] [Indexed: 11/15/2022] Open
Abstract
Amebiasis is a neglected tropical disease which is caused by the protozoan parasite Entamoeba histolytica. This disease is one of the leading causes of diarrhea globally, affecting largely impoverished residents in developing countries. Amebiasis also remains one of the top causes of gastrointestinal diseases in returning international travellers. Despite having many side effects, metronidazole remains the drug of choice as an amebicidal tissue-active agent. However, emergence of metronidazole resistance in pathogens having similar anaerobic metabolism and also in laboratory strains of E. histolytica has necessitated the identification and development of new drug targets and therapeutic strategies against the parasite. Recent research in the field of amebiasis has led to a better understanding of the parasite’s metabolic and cellular pathways and hence has been useful in identifying new drug targets. On the other hand, new molecules effective against amebiasis have been mined by modifying available compounds, thereby increasing their potency and efficacy and also by repurposing existing approved drugs. This review aims at compiling and examining up to date information on promising drug targets and drug molecules for the treatment of amebiasis.
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Affiliation(s)
- Manish T Shrivastav
- Multidisciplinary Centre for Advanced Research and Studies, Jamia Millia Islamia, New Delhi, India
| | - Zainab Malik
- Multidisciplinary Centre for Advanced Research and Studies, Jamia Millia Islamia, New Delhi, India
| | - Somlata
- Multidisciplinary Centre for Advanced Research and Studies, Jamia Millia Islamia, New Delhi, India
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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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Single-Cell RNA Sequencing Reveals that the Switching of the Transcriptional Profiles of Cysteine-Related Genes Alters the Virulence of Entamoeba histolytica. mSystems 2020; 5:5/6/e01095-20. [PMID: 33361325 PMCID: PMC7762796 DOI: 10.1128/msystems.01095-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Studies on the trophozoite of Entamoeba histolytica suggested this organism could accumulate polyploid cells in its proliferative phase and differentiate its cell cycle from that of other eukaryotes. Therefore, a single-cell sequencing technique was used to study the switching of the RNA transcription profiles of single amoebic trophozoites. Entamoeba histolytica is an intestinal protozoan that causes human amoebic colitis and extraintestinal abscesses. Virulence variation is observed in the pathogenicity of E. histolytica trophozoites, but the detailed mechanism remains unclear. Here, a single trophozoite was cultured alone, and the progeny of the trophozoites of each generation were subjected to single-cell RNA sequencing (scRNA-seq) to study the transcriptional profiles of trophozoites. The scRNA-seq analysis indicated the importance of sulfur metabolism and the proteasome pathway in pathogenicity, whereas the isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis did not identify the bulk trophozoites. The trophozoite improved the synthesis of cysteine under cysteine-deficient conditions but downregulated the expression of the intermediate subunit of the lectin of E. histolytica trophozoites and retained the expression of the heavy subunit of lectin, resulting in decreased amoebic phagocytosis and cytotoxicity. The variation in the transmembrane kinase gene family might be critical in regulating the proteasome pathway. Thus, the scRNA-seq technique provided an improved understanding of the biological characteristics and the mechanism of virulence variation of amoebic trophozoites. IMPORTANCE Studies on the trophozoite of Entamoeba histolytica suggested this organism could accumulate polyploid cells in its proliferative phase and differentiate its cell cycle from that of other eukaryotes. Therefore, a single-cell sequencing technique was used to study the switching of the RNA transcription profiles of single amoebic trophozoites. We separated individual trophozoites from axenic cultured trophozoites, CHO cell-incubated trophozoites, and in vivo trophozoites. We found important changes in the sulfur and cysteine metabolism in pathogenicity. The trophozoites strategically regulated the expression of the cysteine-rich protein-encoding genes under cysteine-deficient conditions, thereby decreasing amoebic phagocytosis and cytotoxicity. The single-cell sequencing technique shows evident advantages in comparison with the isobaric tags for relative and absolute quantitation (iTRAQ) proteomic technology (bulk trophozoite level) and reveals the regulation strategy of trophozoites in the absence of exogenous cysteine. This regulation strategy may be the mechanism of virulence variation of amoebic trophozoites.
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Crystal structure of O-Acetylserine sulfhydralase (OASS) isoform 3 from Entamoeba histolytica: Pharmacophore-based virtual screening and validation of novel inhibitors. Eur J Med Chem 2020; 192:112157. [PMID: 32145643 DOI: 10.1016/j.ejmech.2020.112157] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/03/2020] [Accepted: 02/17/2020] [Indexed: 01/09/2023]
Abstract
The l-cysteine is crucial for growth, survival, defense against oxidative stress, and pathogenesis of Entamoeba histolytica. The de novo biosynthesis of l-cysteine in E. histolytica, has a two-step pathway, where O-acetylserine sulfhydrylase (OASS) catalyses the last step by converting OAS to l-cysteine. This pathway is absent in humans and hence represents a promising target for novel therapeutics. E. histolytica expresses three isoforms of OASS and knockdown studies showed the importance of these enzymes for the survival of the pathogen. Here, we report the crystal structure of OASS isoform 3 from E. histolytica to 1.54 Å resolution. The active site geometries and kinetics of EhOASS3 and EhOASS1 structures were found to be very similar. Small-molecule libraries were screened against EhOASS3 and compounds were shortlisted based on the docking scores. F3226-1387 showed best inhibition with IC50 of 38 μM against EhOASS3 and was able to inhibit the growth of the organism to 72%.
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Nagaraja S, Ankri S. Target identification and intervention strategies against amebiasis. Drug Resist Updat 2019; 44:1-14. [PMID: 31112766 DOI: 10.1016/j.drup.2019.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 04/27/2019] [Accepted: 04/30/2019] [Indexed: 12/22/2022]
Abstract
Entamoeba histolytica is the etiological agent of amebiasis, which is an endemic parasitic disease in developing countries and is the cause of approximately 70,000 deaths annually. E. histolytica trophozoites usually reside in the colon as a non-pathogenic commensal in most infected individuals (90% of infected individuals are asymptomatic). For unknown reasons, these trophozoites can become virulent and invasive, cause amebic dysentery, and migrate to the liver where they cause hepatocellular damage. Amebiasis is usually treated either by amebicides which are classified as (a) luminal and are active against the luminal forms of the parasite, (b) tissue and are effective against those parasites that have invaded tissues, and (c) mixed and are effective against the luminal forms of the parasite and those forms which invaded the host's tissues. Of the amebicides, the luminal amebicide, metronidazole (MTZ), is the most widely used drug to treat amebiasis. Although well tolerated, concerns about its adverse effects and the possible emergence of MTZ-resistant strains of E. histolytica have led to the development of new therapeutic strategies against amebiasis. These strategies include improving the potency of existing amebicides, discovering new uses for approved drugs (repurposing of existing drugs), drug rediscovery, vaccination, drug targeting of essential E. histolytica components, and the use of probiotics and bioactive natural products. This review examines each of these strategies in the light of the current knowledge on the gut microbiota of patients with amebiasis.
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Affiliation(s)
- Shruti Nagaraja
- Department of Molecular Microbiology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Serge Ankri
- Department of Molecular Microbiology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
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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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Kabra R, Chauhan N, Kumar A, Ingale P, Singh S. Efflux pumps and antimicrobial resistance: Paradoxical components in systems genomics. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 141:15-24. [PMID: 30031023 PMCID: PMC7173168 DOI: 10.1016/j.pbiomolbio.2018.07.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/10/2018] [Accepted: 07/15/2018] [Indexed: 01/01/2023]
Abstract
Efflux pumps play a major role in the increasing antimicrobial resistance rendering a large number of drugs of no use. Large numbers of pathogens are becoming multidrug resistant due to inadequate dosage and use of the existing antimicrobials. This leads to the need for identifying new efflux pump inhibitors. Design of novel targeted therapies using inherent complexity involved in the biological network modeling has gained increasing importance in recent times. The predictive approaches should be used to determine antimicrobial activities with high pathogen specificity and microbicidal potency. Antimicrobial peptides, which are part of our innate immune system, have the ability to respond to infections and have gained much attention in making resistant strain sensitive to existing drugs. In this review paper, we outline evidences linking host-directed therapy with the efflux pump activity to infectious disease.
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Affiliation(s)
- Ritika Kabra
- National Centre for Cell Science, NCCS Complex, Ganeshkhind, SP Pune University Campus, Pune 411007, India
| | - Nutan Chauhan
- National Centre for Cell Science, NCCS Complex, Ganeshkhind, SP Pune University Campus, Pune 411007, India
| | - Anurag Kumar
- National Centre for Cell Science, NCCS Complex, Ganeshkhind, SP Pune University Campus, Pune 411007, India
| | - Prajakta Ingale
- National Centre for Cell Science, NCCS Complex, Ganeshkhind, SP Pune University Campus, Pune 411007, India
| | - Shailza Singh
- National Centre for Cell Science, NCCS Complex, Ganeshkhind, SP Pune University Campus, Pune 411007, India.
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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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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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