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Alpizar-Sosa E, Zimbres FM, Mantilla BS, Dickie EA, Wei W, Burle-Caldas GA, Filipe LNS, Van Bocxlaer K, Price HP, Ibarra-Meneses AV, Beaudry F, Fernandez-Prada C, Whitfield PD, Barrett MP, Denny PW. Evaluation of the Leishmania Inositol Phosphorylceramide Synthase as a Drug Target Using a Chemical and Genetic Approach. ACS Infect Dis 2024; 10:2913-2928. [PMID: 39023360 PMCID: PMC11320567 DOI: 10.1021/acsinfecdis.4c00284] [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: 04/11/2024] [Revised: 07/01/2024] [Accepted: 07/03/2024] [Indexed: 07/20/2024]
Abstract
The lack of effective vaccines and the development of resistance to the current treatments highlight the urgent need for new anti-leishmanials. Sphingolipid metabolism has been proposed as a promising source of Leishmania-specific targets as these lipids are key structural components of the eukaryotic plasma membrane and are involved in distinct cellular events. Inositol phosphorylceramide (IPC) is the primary sphingolipid in the Leishmania species and is the product of a reaction mediated by IPC synthase (IPCS). The antihistamine clemastine fumarate has been identified as an inhibitor of IPCS in L. major and a potent anti-leishmanial in vivo. Here we sought to further examine the target of this compound in the more tractable species L. mexicana, using an approach combining genomic, proteomic, metabolomic and lipidomic technologies, with molecular and biochemical studies. While the data demonstrated that the response to clemastine fumarate was largely conserved, unexpected disturbances beyond sphingolipid metabolism were identified. Furthermore, while deletion of the gene encoding LmxIPCS had little impact in vitro, it did influence clemastine fumarate efficacy and, importantly, in vivo pathogenicity. Together, these data demonstrate that clemastine does inhibit LmxIPCS and cause associated metabolic disturbances, but its primary target may lie elsewhere.
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Affiliation(s)
| | - Flavia M. Zimbres
- Department
of Biosciences, University of Durham, South Road, Durham, DH1 3LE, U.K.
| | - Brian S. Mantilla
- Department
of Biosciences, University of Durham, South Road, Durham, DH1 3LE, U.K.
| | - Emily A. Dickie
- School
of Infection and Immunity, College of Medical, Veterinary and Life
Sciences, University of Glasgow, Glasgow G12 8TA, U.K.
| | - Wenbin Wei
- Department
of Biosciences, University of Durham, South Road, Durham, DH1 3LE, U.K.
| | - Gabriela A. Burle-Caldas
- Department
of Biosciences, University of Durham, South Road, Durham, DH1 3LE, U.K.
- Departamento
de Bioquímica e Imunologia, Universidade
Federal de Minas Gerais, Caixa Postal 486 31270-901, Belo Horizonte, Minas Gerais, Brazil
| | - Laura N. S. Filipe
- Department
of Biosciences, University of Durham, South Road, Durham, DH1 3LE, U.K.
| | - Katrien Van Bocxlaer
- York
Biomedical Research Institute, Hull York Medical School, University of York, York YO10 5NG, U.K.
| | - Helen P. Price
- School
of Life Sciences, Keele University, Staffordshire, ST5 5BG, U.K.
| | - Ana V. Ibarra-Meneses
- Département
de Pathologie et Microbiologie, Faculté de Médecine
Vétérinaire, Université
de Montréal, Saint-Hyacinthe, Quebec J2S 2M2, Canada
| | - Francis Beaudry
- Département
de Biomédecine, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec J2S 2M2, Canada
| | - Christopher Fernandez-Prada
- Département
de Pathologie et Microbiologie, Faculté de Médecine
Vétérinaire, Université
de Montréal, Saint-Hyacinthe, Quebec J2S 2M2, Canada
| | - Philip D. Whitfield
- School
of Infection and Immunity, College of Medical, Veterinary and Life
Sciences, University of Glasgow, Glasgow G12 8TA, U.K.
| | - Michael P. Barrett
- School
of Infection and Immunity, College of Medical, Veterinary and Life
Sciences, University of Glasgow, Glasgow G12 8TA, U.K.
| | - Paul W. Denny
- Department
of Biosciences, University of Durham, South Road, Durham, DH1 3LE, U.K.
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Roy PK, Paul A, Lalchhuanawmi S, Babu NK, Singh S. Pyridoxal kinase gene deletion leads to impaired growth, deranged redox metabolism and cell cycle arrest in Leishmania donovani. Biochimie 2024; 222:72-86. [PMID: 38403043 DOI: 10.1016/j.biochi.2024.02.009] [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: 09/14/2023] [Revised: 02/19/2024] [Accepted: 02/22/2024] [Indexed: 02/27/2024]
Abstract
Pyridoxal kinase (PdxK) is a vitamin B6 salvage pathway enzyme which produces pyridoxal phosphate. We have investigated the impact of PdxK deletion in Leishmania donovani on parasite survivability, infectivity and cellular metabolism. LdPdxK mutants were generated by gene replacement strategy. All mutants showed significant reduction in growth in comparison to wild type. For PdxK mediated biochemical perturbations, only heterozygous mutants and complementation mutants were used as the growth of null mutants were compromised. Heterozygous mutant showed reduction invitro infectivity and higher cytosolic and mitochondrial ROS levels. Glutathione levels decreased significantly in heterozygous mutant indicating its involvement in cellular oxidative metabolism. Pyridoxal kinase gene deletion resulted in reduced ATP levels in parasites and arrest at G0/G1 phase of cell cycle. All these perturbations were rescued by PdxK gene complementation. This is the first report to confirm that LdPdxK plays an indispensable role in cell survival, pathogenicity, redox metabolism and cell cycle progression of L. donovani parasites. These results provide substantial evidence supporting PdxK as a therapeutic target for the development of specific antileishmanial drug candidates.
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Affiliation(s)
- Pradyot Kumar Roy
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, S.A.S. Nagar, Mohali, 160062, Punjab, India
| | - Anindita Paul
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, S.A.S. Nagar, Mohali, 160062, Punjab, India
| | - Sandra Lalchhuanawmi
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, S.A.S. Nagar, Mohali, 160062, Punjab, India
| | - Neerupudi Kishore Babu
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, S.A.S. Nagar, Mohali, 160062, Punjab, India
| | - Sushma Singh
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, S.A.S. Nagar, Mohali, 160062, Punjab, 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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Goto Y, Ito T, Ghosh S, Mukherjee B. Access and utilization of host-derived iron by Leishmania parasites. J Biochem 2023; 175:17-24. [PMID: 37830941 PMCID: PMC10771036 DOI: 10.1093/jb/mvad082] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/02/2023] [Accepted: 10/05/2023] [Indexed: 10/14/2023] Open
Abstract
Iron is involved in many biochemical processes including oxygen transport, ATP production, DNA synthesis and antioxidant defense. The importance of iron also applies to Leishmania parasites, an intracellular protozoan pathogen causing leishmaniasis. Leishmania are heme-auxotrophs, devoid of iron storage proteins and the heme synthesis pathway. Acquisition of iron and heme from the surrounding niche is thus critical for the intracellular survival of Leishmania inside the host macrophages. Moreover, Leishmania parasites are also exposed to oxidative stress within phagolysosomes of macrophages in mammalian hosts, and they need iron superoxide dismutase for overcoming this stress. Therefore, untangling the strategy adopted by these parasites for iron acquisition and utilization can be good targets for the development of antileishmanial drugs. Here, in this review, we will address how Leishmania parasites acquire and utilize iron and heme during infection to macrophages.
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Affiliation(s)
- Yasuyuki Goto
- Laboratory of Molecular Immunology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Tatsumi Ito
- Laboratory of Molecular Immunology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Souradeepa Ghosh
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India
| | - Budhaditya Mukherjee
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India
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Singh R, Kashif M, Srivastava P, Manna PP. Recent Advances in Chemotherapeutics for Leishmaniasis: Importance of the Cellular Biochemistry of the Parasite and Its Molecular Interaction with the Host. Pathogens 2023; 12:pathogens12050706. [PMID: 37242374 DOI: 10.3390/pathogens12050706] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
Leishmaniasis, a category 1 neglected protozoan disease caused by a kinetoplastid pathogen called Leishmania, is transmitted through dipteran insect vectors (phlebotomine, sand flies) in three main clinical forms: fatal visceral leishmaniasis, self-healing cutaneous leishmaniasis, and mucocutaneous leishmaniasis. Generic pentavalent antimonials have long been the drug of choice against leishmaniasis; however, their success is plagued with limitations such as drug resistance and severe side effects, which makes them redundant as frontline therapy for endemic visceral leishmaniasis. Alternative therapeutic regimens based on amphotericin B, miltefosine, and paromomycin have also been approved. Due to the unavailability of human vaccines, first-line chemotherapies such as pentavalent antimonials, pentamidine, and amphotericin B are the only options to treat infected individuals. The higher toxicity, adverse effects, and perceived cost of these pharmaceutics, coupled with the emergence of parasite resistance and disease relapse, makes it urgent to identify new, rationalized drug targets for the improvement in disease management and palliative care for patients. This has become an emergent need and more relevant due to the lack of information on validated molecular resistance markers for the monitoring and surveillance of changes in drug sensitivity and resistance. The present study reviewed the recent advances in chemotherapeutic regimens by targeting novel drugs using several strategies including bioinformatics to gain new insight into leishmaniasis. Leishmania has unique enzymes and biochemical pathways that are distinct from those of its mammalian hosts. In light of the limited number of available antileishmanial drugs, the identification of novel drug targets and studying the molecular and cellular aspects of these drugs in the parasite and its host is critical to design specific inhibitors targeting and controlling the parasite. The biochemical characterization of unique Leishmania-specific enzymes can be used as tools to read through possible drug targets. In this review, we discuss relevant metabolic pathways and novel drugs that are unique, essential, and linked to the survival of the parasite based on bioinformatics and cellular and biochemical analyses.
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Affiliation(s)
- Ranjeet Singh
- Immunobiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Mohammad Kashif
- Immunobiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Prateek Srivastava
- Immunobiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Partha Pratim Manna
- Immunobiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
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Paul A, Roy PK, Babu NK, Dhumal TT, Singh S. Leishmania donovani 6-phosphogluconolactonase: Crucial for growth and host infection? Microb Pathog 2023; 178:106082. [PMID: 36958644 DOI: 10.1016/j.micpath.2023.106082] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/14/2023] [Accepted: 03/19/2023] [Indexed: 03/25/2023]
Abstract
The hexose monophosphate shunt is a crucial pathway in a variety of microorganisms owing to its vital metabolic products and intermediates such as NADPH, ribose 5-phosphate etc. The enzyme 6-phosphogluconolactonase catalyses the second step of this pathway, converting 6-phosphogluconolactone to 6-phosphogluconic acid. This enzyme has been known to have a significant involvement in growth, pathogenesis and sensitivity to oxidative stress in bacterial and protozoal pathogens. However, the functional role of kinetoplastid Leishmania donovani 6-phospohogluconolactonase (Ld6PGL) remains unexplored. L. donovani is the second largest parasitic killer and causative organism of life threatening visceral leishmaniasis. To understand its possible functional role in the parasite, the alleles of Ld6PGL were sequentially knocked-out followed by gene complementation. The Ld6PGL mutant cell lines showed decrease in transcriptional and translational expression as well as in the enzyme activity. In case of Ld6PGL null mutants, approximately 2-fold reduction was observed in growth. The null mutants also showed ∼38% decrease in infectivity, which recovered to ∼15% on complementation. Scanning electron microscopy showed a marked decrease in flagellar length in the knockout parasites. When treated with the standard drug miltefosine, the mutant strains had no significant change in the drug sensitivity. However, the Ld6PGL mutants were more susceptible to oxidative stress. Our findings suggest that 6PGL is required for parasite growth and infection but it is not essential.
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Affiliation(s)
- Anindita Paul
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062, Punjab, India
| | - Pradyot Kumar Roy
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062, Punjab, India
| | - Neerupudi Kishore Babu
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062, Punjab, India
| | - Tushar Tukaram Dhumal
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062, Punjab, India
| | - Sushma Singh
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062, Punjab, India.
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The ChaC family of γ-glutamyl cyclotransferases is required for Leishmania to switch to a slow growth state and for long-term survival of the parasite. J Biol Chem 2022; 298:102510. [PMID: 36126772 PMCID: PMC9586994 DOI: 10.1016/j.jbc.2022.102510] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/12/2022] [Accepted: 09/14/2022] [Indexed: 11/24/2022] Open
Abstract
The ChaC family of γ-glutamyl cyclotransferases is conserved throughout all Kingdoms and catalyzes the degradation of GSH. So far, the ChaC family proteins in trypanosomal parasites are missing in the literature. Here, we report two members of the ChaC family of γ-glutamyl cyclotransferases (LmChaC2a and LmChaC2b) in the unicellular pathogen Leishmania. Activity measurements suggest that these proteins catalyze degradation of GSH but no other γ-glutamyl peptides. Recombinant LmChaC2a protein shows ∼17-fold lower catalytic efficiency (kcat ∼ 0.9 s−1) than LmChaC2b (kcat ∼ 15 s−1), although they showed comparable Km values (∼1.75 mM for LmChaC2a and ∼2.0 mM for LmChaC2b) toward GSH. qRT-PCR and Western blot analyses suggest that the LmChaC2a protein was found to be constitutively expressed, whereas LmChaC2b was regulated by sulfur stress. To investigate its precise physiological function in Leishmania, we generated overexpressed, knockout, and complement cell lines. Flow cytometric analyses show the presence of a higher intracellular GSH concentration and lower intracellular ROS level, indicative of a more reductive environment in null mutants. We found LmChaC2-expressing cells grow in GSH-containing sulfur-limited media, while the null mutants failed to grow, suggesting that LmChaC2 is crucial for cell growth with GSH as the only sulfur source. Null mutants, although reach the stationary phase rapidly, display impaired long-term survival, indicating that LmChaC2-mediated GSH degradation is necessary for prolonged survival. In vivo studies suggest that LmChaC2-dependent controlled GSH degradation promotes chronic infection by the parasite. Altogether, these data indicate that LmChaC2 plays an important role in GSH homeostasis in Leishmania.
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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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Docampo R, Vercesi AE. Mitochondrial Ca 2+ and Reactive Oxygen Species in Trypanosomatids. Antioxid Redox Signal 2022; 36:969-983. [PMID: 34218689 PMCID: PMC9125514 DOI: 10.1089/ars.2021.0058] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/31/2021] [Accepted: 06/22/2021] [Indexed: 02/06/2023]
Abstract
Significance: Millions of people are infected with trypanosomatids and new therapeutic approaches are needed. Trypanosomatids possess one mitochondrion per cell and its study has led to discoveries of general biological interest. These mitochondria, as in their animal counterparts, generate reactive oxygen species (ROS) and have evolved enzymatic and nonenzymatic defenses against them. Mitochondrial calcium ion (Ca2+) overload leads to generation of ROS and its study could lead to relevant information on the biology of trypanosomatids and to novel drug targets. Recent Advances: Mitochondrial Ca2+ is normally involved in maintaining the bioenergetics of trypanosomes, but when Ca2+ overload occurs, it is associated with cell death. Trypanosomes lack key players in the mechanism of cell death described in mammalian cells, although mitochondrial Ca2+ overload results in collapse of their membrane potential, production of ROS, and cytochrome c release. They are also very resistant to mitochondrial permeability transition, and cell death after mitochondrial Ca2+ overload depends on generation of ROS. Critical Issues: In this review, we consider the mechanisms of mitochondrial oxidant generation and removal and the involvement of Ca2+ in trypanosome cell death. Future Directions: More studies are required to determine the reactions involved in generation of ROS by the mitochondria of trypanosomatids, their enzymatic and nonenzymatic defenses against ROS, and the occurrence and composition of a mitochondrial permeability transition pore. Antioxid. Redox Signal. 36, 969-983.
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Affiliation(s)
- Roberto Docampo
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
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10
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Das A, Kamran M, Ali N. HO-3867 Induces ROS-Dependent Stress Response and Apoptotic Cell Death in Leishmania donovani. Front Cell Infect Microbiol 2021; 11:774899. [PMID: 34926321 PMCID: PMC8677699 DOI: 10.3389/fcimb.2021.774899] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/12/2021] [Indexed: 12/12/2022] Open
Abstract
Lack of vaccine and increasing chemotherapeutic toxicities currently necessitate the development of effective and safe drugs against various forms of leishmaniases. We characterized the cellular stress induced by a novel curcumin analogue, HO-3867, encapsulated within the phosphatidylcholine-stearylamine (PC-SA) liposome for the first time against Leishmania. The liposomal formulation of HO-3867 (i.e., PC-SA/HO-3867) initiated oxidative stress-induced apoptosis in L. donovani, revealed by altered cell morphology, phosphatidylserine externalization, mitochondrial depolarization, intracellular lipid accumulation, and cell cycle arrest in promastigotes. Liposomal HO-3867 was observed to be a strong apoptosis inducer in L. donovani and L. major in a dose-dependent manner, yet completely safe for normal murine macrophages. Moreover, PC-SA/HO-3867 treatment induced L. donovani metacaspase and PARP1 activation along with downregulation of the Sir2 gene. PC-SA/HO-3867 arrested intracellular L. donovani amastigote burden in vitro, with reactive oxygen species (ROS) and nitric oxide (NO)-mediated parasite killing. These data suggest that liposomal HO-3867 represents a highly promising and non-toxic nanoparticle-based therapeutic platform against leishmaniasis inspiring further preclinical developments.
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Affiliation(s)
| | | | - Nahid Ali
- Infectious Diseases and Immunology Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Chemical Biology, Kolkata, India
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Glyceraldehyde-3-phosphate dehydrogenase present in extracellular vesicles from Leishmania major suppresses host TNF-alpha expression. J Biol Chem 2021; 297:101198. [PMID: 34534548 PMCID: PMC8502904 DOI: 10.1016/j.jbc.2021.101198] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/08/2021] [Accepted: 09/13/2021] [Indexed: 11/23/2022] Open
Abstract
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) fulfills various physiological roles that are unrelated to its glycolytic function. However, to date, the nonglycolytic function of GAPDH in trypanosomal parasites is absent from the literature. Exosomes secreted from Leishmania, like entire parasites, were found to have a significant impact on macrophage cell signaling and function, indicating cross talk with the host immune system. In this study, we demonstrate that the Leishmania GAPDH (LmGAPDH) protein is highly enriched within the extracellular vesicles (EVs) secreted during infection. To understand the function of LmGAPDH in EVs, we generated control, overexpressed, half-knockout (HKO), and complement cell lines. HKO cells displayed lower virulence compared with control cells when macrophages and BALB/c mice were infected with them, implying a crucial role for LmGAPDH in Leishmania infection and disease progression. Furthermore, upon infection of macrophages with HKO mutant Leishmania and its EVs, despite no differences in TNFA mRNA expression, there was a considerable increase in TNF-α protein expression compared with control, overexpressed, and complement parasites as determined by ELISA, RT-PCR, and immunoblot data. In vitro protein translation studies suggest that LmGAPDH-mediated TNF-α suppression occurs in a concentration-dependent manner. Moreover, mRNA binding assays also verified that LmGAPDH binds to the AU-rich 3′-UTR region of TNFA mRNA, limiting its production. Together, these findings confirmed that the LmGAPDH contained in EVs inhibits TNF-α expression in macrophages during infection via posttranscriptional repression.
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Mondal DK, Pal DS, Abbasi M, Datta R. Functional partnership between carbonic anhydrase and malic enzyme in promoting gluconeogenesis in
Leishmania major. FEBS J 2021; 288:4129-4152. [DOI: 10.1111/febs.15720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 11/29/2020] [Accepted: 01/15/2021] [Indexed: 12/24/2022]
Affiliation(s)
- Dipon Kumar Mondal
- Department of Biological Sciences Indian Institute of Science Education and Research (IISER) Kolkata Mohanpur India
| | - Dhiman Sankar Pal
- Department of Biological Sciences Indian Institute of Science Education and Research (IISER) Kolkata Mohanpur India
| | - Mazharul Abbasi
- Department of Biological Sciences Indian Institute of Science Education and Research (IISER) Kolkata Mohanpur India
| | - Rupak Datta
- Department of Biological Sciences Indian Institute of Science Education and Research (IISER) Kolkata Mohanpur India
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Kumar V, Ghosh S, Roy K, Pal C, Singh S. Deletion of Glutamine Synthetase Gene Disrupts the Survivability and Infectivity of Leishmania donovani. Front Cell Infect Microbiol 2021; 11:622266. [PMID: 33732662 PMCID: PMC7959746 DOI: 10.3389/fcimb.2021.622266] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/25/2021] [Indexed: 12/24/2022] Open
Abstract
Glutamine synthetase (GS) is one of the most important metabolic enzymes which catalyzes ligation of glutamate and ammonia to form glutamine. Previous studies from our lab had revealed significant differences in parasite and host GS enzyme which warranted us to further work on its relevance in parasite. To analyze glutamine synthetase function in Leishmania, we generated GS overexpressors and knockout mutants and evaluated their ability to grow in vitro in monocyte differentiated macrophage and in vivo by infections in BALB/c mice. GS knocked out strain showed significant growth retardation with delayed cell cycle progression and morphological alteration. Null mutants exhibited attenuated infectivity both in in vitro and in vivo experiments and the effect was reverted back when infected with GS complemented parasites. This indicated that the alterations in phenotype observed were indeed due to GS knockout. GS knockout also made the parasite increasingly sensitive to Miltefosine. Detailed investigation of mode of parasite death upon Miltefosine treatment by dual staining with Annexin-V conjugated FITC and propidium iodide, pointed towards apoptotic or necrotic mode of cell death. This is the first report to confirm that GS is essential for the survivability and infectivity of Leishmania donovani, and can be exploited as a potential drug-target.
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Affiliation(s)
- Vinay Kumar
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Mohali, India
| | - Sanhita Ghosh
- Cellular Immunology and Experimental Therapeutics Laboratory, Department of Zoology, West Bengal State University, Barasat, India
| | - Kamalika Roy
- Cellular Immunology and Experimental Therapeutics Laboratory, Department of Zoology, West Bengal State University, Barasat, India
| | - Chiranjib Pal
- Cellular Immunology and Experimental Therapeutics Laboratory, Department of Zoology, West Bengal State University, Barasat, India
| | - Sushma Singh
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Mohali, India
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Leishmanicidal Activity of an In Silico-Screened Novel Inhibitor against Ascorbate Peroxidase of Leishmania donovani. Antimicrob Agents Chemother 2020; 64:AAC.01766-19. [PMID: 32366716 DOI: 10.1128/aac.01766-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 04/27/2020] [Indexed: 01/14/2023] Open
Abstract
Peroxidases are a heterogeneous family of enzymes that have diverse biological functions. Ascorbate peroxidase is a redox enzyme that is reduced by trypanothione, which plays a central role in the redox defense system of Leishmania In view of developing new and novel therapeutics, we performed in silico studies in order to search for a ligand library and identify new drug candidates and their physiological roles against promastigotes and intracellular amastigotes of Leishmania donovani Our results demonstrated that the selected inhibitor ZINC96021026 has significant antileishmanial effect and effectively killed both free and intracellular forms of the parasite. ZINC96021026 was found to be identical to ML-240, a selective inhibitor of valosin-containing protein (VCP), or p97, a member of the AAA-ATPase protein family which was derived from the scaffold of N 2,N 4-dibenzylquinazoline-2,4-diamine (DBeQ), targeting the D2-ATPase domain of the enzyme. ZINC96021026 (ML-240) thus has a broad range of cellular functions, thought to be derived from its ability to unfold proteins or disassemble protein complexes, besides inhibiting the ascorbate peroxidase activity. ML-240 may inhibit the parasite's ascorbate peroxidase, leading to extensive apoptosis and inducing generation of reactive oxygen species. Taken together, our results demonstrated that ML-240 could be an attractive therapeutic option for treatment against leishmaniasis.
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15
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Adinehbeigi K, Shaddel M, Khalili S, Zakeri A. Suramin could block the activity of Arabinono-1, 4-lactone oxidase enzyme from Leishmania donovani: structure-based screening and molecular dynamics analyses. Trans R Soc Trop Med Hyg 2020; 114:162-172. [PMID: 31667504 DOI: 10.1093/trstmh/trz091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/07/2019] [Accepted: 08/02/2019] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Leishmania donovani, a parasitic protozoan causing visceral leishmaniasis, can lead to a dangerous and often fatal disease in humans. Current treatment for leishmaniasis may have severe side effects, low efficacy and high cost, hence an immediate need for new efficient drugs is essential. Arabinono-1, 4-lactone oxidase enzyme from Leishmania donovani (LdALO), which catalyzes the last step of the ascorbate biosynthesis pathway, has been considered as a potential target for antileishmanial drugs design. METHODS The current study was performed with an in silico approach to predict novel inhibitory molecules against the LdALO enzyme. Various modeling and refinement processes were employed to obtain a reliable 3D structure. RESULTS The best LdALO model with the highest qualitative model energy analysis score was predicted by the Robetta server and subsequently refined by 3D refine and ModLoop servers. The high quality of the final LdALO model was confirmed using model assessment software. Based on docking analysis results, we predicted 10 inhibitory molecules of a US Food and Drug Administration-approved library, with appropriate criteria regarding energy binding and interaction with the main functionally active sites of LdALO, indicating that they could be significant targets for further drug design investigations against L. donovani. CONCLUSION Suramin is used to treat the first stage of African sleeping sickness and its mechanism of action is unknown. Our results showed that suramin was the best-predicted inhibitor compound for LdALO enzyme activity.
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Affiliation(s)
- Keivan Adinehbeigi
- Department of Parasitology and Mycology, Faculty of Medicine, AJA University of Medical Sciences, Etemad Zadeh Street, Fatemi Street, Tehran, Iran
| | - Minoo Shaddel
- Department of Parasitology and Mycology, Faculty of Medicine, AJA University of Medical Sciences, Etemad Zadeh Street, Fatemi Street, Tehran, Iran
| | - Saeed Khalili
- Department of Biology Science, Shahid Rajaee University, Tehran, Iran
| | - Alireza Zakeri
- Department of Biology Science, Shahid Rajaee University, Tehran, Iran
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16
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Aoki JI, Laranjeira-Silva MF, Muxel SM, Floeter-Winter LM. The impact of arginase activity on virulence factors of Leishmania amazonensis. Curr Opin Microbiol 2019; 52:110-115. [DOI: 10.1016/j.mib.2019.06.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 05/10/2019] [Accepted: 06/14/2019] [Indexed: 02/04/2023]
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17
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PAS domain-containing phosphoglycerate kinase deficiency in Leishmania major results in increased autophagosome formation and cell death. Biochem J 2019; 476:1303-1321. [PMID: 30988012 DOI: 10.1042/bcj20190041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/08/2019] [Accepted: 04/12/2019] [Indexed: 11/17/2022]
Abstract
Per-Arnt-Sim (PAS) domains are structurally conserved and present in numerous proteins throughout all branches of the phylogenetic tree. Although PAS domain-containing proteins are major players for the adaptation to environmental stimuli in both prokaryotic and eukaryotic organisms, these types of proteins are still uncharacterized in the trypanosomatid parasites, Trypanosome and Leishmania In addition, PAS-containing phosphoglycerate kinase (PGK) protein is uncharacterized in the literature. Here, we report a PAS domain-containing PGK (LmPAS-PGK) in the unicellular pathogen Leishmania The modeled structure of N-terminal of this protein exhibits four antiparallel β sheets centrally flanked by α helices, which is similar to the characteristic signature of PAS domain. Activity measurements suggest that acidic pH can directly stimulate PGK activity. Localization studies demonstrate that the protein is highly enriched in the glycosome and its presence can also be seen in the lysosome. Gene knockout, overexpression and complement studies suggest that LmPAS-PGK plays a fundamental role in cell survival through autophagy. Furthermore, the knockout cells display a marked decrease in virulence when host macrophage and BALB/c mice were infected with them. Our work begins to clarify how acidic pH-dependent ATP generation by PGK is likely to function in cellular adaptability of Leishmania.
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18
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Meshram RJ, Goundge MB, Kolte BS, Gacche RN. An in silico approach in identification of drug targets in Leishmania: A subtractive genomic and metabolic simulation analysis. Parasitol Int 2018; 69:59-70. [PMID: 30503238 DOI: 10.1016/j.parint.2018.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 10/17/2018] [Accepted: 11/28/2018] [Indexed: 12/26/2022]
Abstract
Leishmaniasis is one of the major health issue in developing countries. The current therapeutic regimen for this disease is less effective with lot of adverse effects thereby warranting an urgent need to develop not only new and selective drug candidates but also identification of effective drug targets. Here we present subtractive genomics procedure for identification of putative drug targets in Leishmania. Comprehensive druggability analysis has been carried out in the current work for identified metabolic pathways and drug targets. We also demonstrate effective metabolic simulation methodology to pinpoint putative drug targets in threonine biosynthesis pathway. Metabolic simulation data from the current study indicate that decreasing flux through homoserine kinase reaction can be considered as a good therapeutic opportunity. The data from current study is expected to show new avenue for designing experimental strategies in search of anti-leishmanial agents.
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Affiliation(s)
- Rohan J Meshram
- Bioinformatics Centre, Savitribai Phule Pune University, Pune 411007, India.
| | - Mayuri B Goundge
- Bioinformatics Centre, Savitribai Phule Pune University, Pune 411007, India
| | - Baban S Kolte
- Bioinformatics Centre, Savitribai Phule Pune University, Pune 411007, India; Department of Biotechnology, Savitribai Phule Pune University, Pune 411007, India
| | - Rajesh N Gacche
- Department of Biotechnology, Savitribai Phule Pune University, Pune 411007, India
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19
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Moreira DDS, Xavier MV, Murta SMF. Ascorbate peroxidase overexpression protects Leishmania braziliensis against trivalent antimony effects. Mem Inst Oswaldo Cruz 2018; 113:e180377. [PMID: 30507997 PMCID: PMC6251480 DOI: 10.1590/0074-02760180377] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 10/17/2018] [Indexed: 02/21/2023] Open
Abstract
Ascorbate peroxidase (APX) is a redox enzyme of the trypanothione pathway that converts hydrogen peroxide (H2O2) into water molecules. In the present study, the APX gene was overexpressed in Leishmania braziliensis to investigate its contribution to the trivalent antimony (SbIII)-resistance phenotype. Western blot results demonstrated that APX-overexpressing parasites had higher APX protein levels in comparison with the wild-type line (LbWTS). APX-overexpressing clones showed an 8-fold increase in the antimony-resistance index over the parental line. In addition, our results indicated that these clones were approximately 1.8-fold more tolerant to H2O2 than the LbWTS line, suggesting that the APX enzyme plays an important role in the defence against oxidative stress. Susceptibility tests revealed that APX-overexpressing L. braziliensis lines were more resistant to isoniazid, an antibacterial agent that interacts with APX. Interestingly, this compound enhanced the anti-leishmanial SbIII effect, indicating that this combination represents a good strategy for leishmaniasis chemotherapy. Our data demonstrate that APX enzyme is involved in the development of L. braziliensis antimony-resistance phenotype and may be an attractive therapeutic target in the design of new strategies for leishmaniasis treatment.
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20
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Prakash J, Yadav S, Saha G, Chiranjivi AK, Kumar S, Sasidharan S, Saudagar P, Dubey VK. Episomal expression of human glutathione reductase (HuGR) in Leishmania sheds light on evolutionary pressure for unique redox metabolism pathway: Impaired stress tolerance ability of Leishmania donovani. Int J Biol Macromol 2018; 121:498-507. [PMID: 30316767 DOI: 10.1016/j.ijbiomac.2018.10.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 09/30/2018] [Accepted: 10/10/2018] [Indexed: 11/26/2022]
Abstract
Trypanothione based redox metabolism is unique to the Trypanosomatida family. Despite extensive studies on redox metabolism of Leishmania parasites, a prominent question of why Leishmania adopt this unique redox pathway remains elusive. We have episomally expressed human glutathione reductase (HuGR) in Leishmania donovani (LdGR+) and investigated its effect. LdGR+ strain has slower growth compared to the wild type (Ld) indicating decreased survival ability of the strain. Further, LdGR+ strain showed enhanced accumulation of intracellular reactive oxygen species (ROS) and more sensitivity to the anti-leishmanial drug, Miltefosine, inferring increased stress level. In contrast, the expression analyses of genes specific to redox metabolism were increased significantly in LdGR+ strain compared to wild type. Lower infectivity index of the LdGR+ strain substantiated the above findings and indicated that the expression of HuGR reduces the stress tolerance ability of the parasite. From molecular docking studies with HuGR, it was observed that oxidized trypanothione (TS2) binds much better than oxidized glutathione (GS2). These results also give us hints that the parasite is losing infectivity potential due to an overall increase in intracellular stress caused with the expression of HuGR, showcasing a possible role of evolutionary pressure on the Leishmania parasites posed by HuGR.
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Affiliation(s)
- Jay Prakash
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Sunita Yadav
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India; School of Biochemical Engineering, Indian Institute of Technology (BHU) Varanasi, Varanasi 221005, India
| | - Gundappa Saha
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Adarsh Kumar Chiranjivi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Suresh Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Santanu Sasidharan
- Department of Biotechnology, National Institute of Technology, Warangal 506004, India
| | - Prakash Saudagar
- Department of Biotechnology, National Institute of Technology, Warangal 506004, India.
| | - Vikash Kumar Dubey
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India; School of Biochemical Engineering, Indian Institute of Technology (BHU) Varanasi, Varanasi 221005, India.
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21
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Sarwar HS, Akhtar S, Sohail MF, Naveed Z, Rafay M, Nadhman A, Yasinzai M, Shahnaz G. Redox biology of Leishmania and macrophage targeted nanoparticles for therapy. Nanomedicine (Lond) 2017. [DOI: 10.2217/nnm-2017-0049] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Intramacrophage parasite ‘Leishmania’ has developed various mechanisms for proficient uptake into macrophages and phagosome regulation to avoid macrophage's oxidative burst induced by peroxide, hydroxyl radical, hypochlorous acid and peroxynitrite production. One major barrier for impairing the accession of old fashioned anti-Leishmanial drugs is intrinsic incapability to pass through cell membranes and limiting their abilities to ultimately destroy intracellular pathogens. Receptor-mediated targeted drug delivery to the macrophages by using nanoparticles emerges as promising strategy to improve therapeutic efficacy of old-fashioned drug. Receptor-mediated targeted nanoparticles can migrate across the cell membrane barriers and release enclosed drug cargo at sites of infection. This review is focusing on Leishmania-macrophage signaling alterations, its association with drug resistance and role of nanoparticles for receptor mediated macrophage targeting.
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Affiliation(s)
| | - Sohail Akhtar
- Department of Entomology, University College of Agriculture & Environmental Sciences, The Islamia University, Bahawalpur, Pakistan
| | - Muhammad Farhan Sohail
- Department of Pharmacy, Quaid-i-Azam University, Islamabad 45320, Pakistan
- Harvard-MIT Division of Health Sciences & Technology, Massachusetts Institute of Technology, Cambridge, MA 0213, USA
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Lahore Campus, Lahore 54000, Pakistan
| | - Zaeema Naveed
- Department of Epidemiology, College of Public Health, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Muhammad Rafay
- Department of Forestry, Range & Wild Life Management, University College of Agriculture & Environmental Sciences, The Islamia University, Bahawalpur, Pakistan
| | - Akhtar Nadhman
- Centre for Interdisciplinary Research in Basic Sciences, International Islamic University, Islamabad, Pakistan
| | - Masoom Yasinzai
- Centre for Interdisciplinary Research in Basic Sciences, International Islamic University, Islamabad, Pakistan
| | - Gul Shahnaz
- Department of Pharmacy, Quaid-i-Azam University, Islamabad 45320, Pakistan
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In Vitro Evaluation of Antileishmanial Activity of Computationally Screened Compounds against Ascorbate Peroxidase To Combat Amphotericin B Drug Resistance. Antimicrob Agents Chemother 2017; 61:AAC.02429-16. [PMID: 28461317 DOI: 10.1128/aac.02429-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 03/28/2017] [Indexed: 12/11/2022] Open
Abstract
In visceral leishmaniasis (VL), the host macrophages generate oxidative stress to destroy the pathogen, while Leishmania combats the harmful effect of radicals by redox homeostasis through its unique trypanothione cascade. Leishmania donovani ascorbate peroxidase (LdAPx) is a redox enzyme that regulates the trypanothione cascade and detoxifies the effect of H2O2 The absence of an LdAPx homologue in humans makes it an excellent drug target. In this study, the homology model of LdAPx was built, including heme, and diverse compounds were prefiltered (PAINS, ADMET, and Lipinski's rule of five) and thereafter screened against the LdAPx model. Compounds having good affinity in terms of the Glide XP (extra precision) score were clustered to select diverse compounds for experimental validation. A total of 26 cluster representatives were procured and tested on promastigote culture, yielding 12 compounds with good antileishmanial activity. Out of them, six compounds were safer on the BALB/c peritoneal macrophages and were also effective against disease-causing intracellular amastigotes. Three out of six compounds inhibited recombinant LdAPx in a noncompetitive manner and also demonstrated partial reversion of the resistance property in an amphotericin B (AmB)-resistant strain, which may be due to an increased level of reactive oxygen species (ROS) and decrease of glutathione (GSH) content. However, inhibition of LdAPx in resistant parasites enhanced annexin V staining and activation of metacaspase-like protease activity, which may help in DNA fragmentation and apoptosis-like cell death. Thus, the present study will help in the search for specific hits and templates of potential therapeutic interest and therefore may facilitate the development of new drugs for combination therapy against VL.
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Han J, Gao P, Zhao S, Bie X, Lu Z, Zhang C, Lv F. iTRAQ-based proteomic analysis of LI-F type peptides produced by Paenibacillus polymyxa JSa-9 mode of action against Bacillus cereus. J Proteomics 2017; 150:130-140. [DOI: 10.1016/j.jprot.2016.08.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 07/04/2016] [Accepted: 08/25/2016] [Indexed: 11/29/2022]
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Zaidi A, Singh KP, Ali V. Leishmania and its quest for iron: An update and overview. Mol Biochem Parasitol 2016; 211:15-25. [PMID: 27988301 DOI: 10.1016/j.molbiopara.2016.12.004] [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: 05/16/2016] [Revised: 11/21/2016] [Accepted: 12/11/2016] [Indexed: 12/12/2022]
Abstract
Parasites of genus Leishmania are the causative agents of complex neglected diseases called leishmaniasis and continue to be a significant health concern globally. Iron is a vital nutritional requirement for virtually all organisms, including pathogenic trypanosomatid parasites, and plays a crucial role in many facets of cellular metabolism as a cofactor of several enzymes. Iron acquisition is essential for the survival of parasites. Yet parasites are also vulnerable to the toxicity of iron and reactive oxygen species. The aim of this review is to provide an update on the current knowledge about iron acquisition and usage by Leishmania species. We have also discussed about host strategy to modulate iron availability and the strategies deployed by Leishmania parasites to overcome iron withholding defences and thus favour parasite growth within host macrophages. Since iron plays central roles in the host's response and parasite metabolism, a comprehensive understanding of the iron metabolism is beneficial to identify potential viable therapeutic opportunities against leishmaniasis.
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Affiliation(s)
- Amir Zaidi
- Laboratory of Molecular Biochemistry and Cell Biology, Dept. of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna, India
| | - Krishn Pratap Singh
- Laboratory of Molecular Biochemistry and Cell Biology, Dept. of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna, India
| | - Vahab Ali
- Laboratory of Molecular Biochemistry and Cell Biology, Dept. of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna, India.
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Anand S, Madhubala R. Genetically Engineered Ascorbic acid-deficient Live Mutants of Leishmania donovani induce long lasting Protective Immunity against Visceral Leishmaniasis. Sci Rep 2015; 5:10706. [PMID: 26035062 PMCID: PMC4451804 DOI: 10.1038/srep10706] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 04/22/2015] [Indexed: 11/18/2022] Open
Abstract
Visceral leishmaniasis caused by Leishmania donovani is the most severe systemic form of the disease. There are still no vaccines available for humans and there are limitations associated with the current therapeutic regimens for leishmaniasis. Recently, we reported functional importance of Arabino-1, 4-lactone oxidase (ALO) enzyme from L. donovani involved in ascorbate biosynthesis pathway. In this study, we have shown that ΔALO parasites do not affect the ability of null mutants to invade visceral organs but severely impair parasite persistence beyond 16 week in BALB/c mice and hence are safe as an immunogen. Both short term (5 week) and long term (20 week) immunization with ΔALO parasites conferred sustained protection against virulent challenge in BALB/c mice, activated splenocytes and resulted in induction of pro-inflammatory cytokine response. Protection in immunized mice after challenge correlated with the stimulation of IFN-γ producing CD4+ and CD8+ T cells. Antigen-mediated cell immunity correlated with robust nitrite and superoxide generation, macrophage-derived oxidants critical in controlling Leishmania infection. Our data shows that live attenuated ΔALO parasites are safe, induce protective immunity and can provide sustained protection against Leishmania donovani. We further conclude that the parasites attenuated in their anti-oxidative defence mechanism can be exploited as vaccine candidates.
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Affiliation(s)
- Sneha Anand
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Rentala Madhubala
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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26
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Purkait B, Singh R, Wasnik K, Das S, Kumar A, Paine M, Dikhit M, Singh D, Sardar AH, Ghosh AK, Das P. Up-regulation of silent information regulator 2 (Sir2) is associated with amphotericin B resistance in clinical isolates of Leishmania donovani. J Antimicrob Chemother 2015; 70:1343-56. [PMID: 25667407 DOI: 10.1093/jac/dku534] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 11/30/2014] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVE Silent information regulator 2 (Sir2) is involved in parasite survival and apoptosis. Here, we aimed to explore the involvement of Sir2 in amphotericin B (AmB) resistance mechanism in Leishmania donovani. METHODS The expression levels of Sir2, MDR1 and NAD(+) biosynthetic pathway enzymes in AmB-resistant and -susceptible parasites were measured and total intracellular NAD(+)/NADH ratios were compared. Overexpression and knockout constructs of Sir2 were transfected in AmB-resistant and -susceptible parasites. Both resistant and susceptible parasites were inhibited with sirtinol for 4 h. The deacetylase activity of Sir2, the expression level of MDR1, the rate of AmB efflux, concentrations of reactive oxygen species (ROS) and levels of apoptosis were examined in WT, inhibited and transfected parasites, and the AmB susceptibility of the respective parasites was measured by determining the LD50 of AmB. RESULTS Levels of mRNA, protein and NAD(+)-dependent deacetylase activity of Sir2 were elevated in resistant versus susceptible parasites. Inhibition and/or deletion of Sir2 allele showed a decreased mRNA level of MDR1, lower drug efflux, increased ROS concentration, apoptosis-like phenomenon and decreased LD50 of AmB in resistant parasites. In contrast, Sir2 overexpression in susceptible parasites reversed drug susceptibility producing a resistant phenotype. This was associated with increased LD50 of AmB along with increased expression levels of MDR1, drug efflux and reduced concentrations of ROS, corresponding to decreased apoptosis of resistant to WT sensitive. CONCLUSIONS Sir2 plays a critical role in AmB resistance by regulating MDR1, ROS concentration and apoptosis-like phenomena and may be a new resistance marker for visceral leishmaniasis.
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Affiliation(s)
- Bidyut Purkait
- Department of Molecular Parasitology and Bioinformatics, Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Agamkuan, Patna, 800007 Bihar, India
| | - Ruby Singh
- Department of Molecular Parasitology and Bioinformatics, Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Agamkuan, Patna, 800007 Bihar, India
| | - Kirti Wasnik
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Hajipur, Bihar, India
| | - Sushmita Das
- Department of Microbiology, All India Institute of Medical Sciences, Patna, India
| | - Ashish Kumar
- Department of Molecular Parasitology and Bioinformatics, Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Agamkuan, Patna, 800007 Bihar, India
| | - Mark Paine
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Manas Dikhit
- Department of Molecular Parasitology and Bioinformatics, Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Agamkuan, Patna, 800007 Bihar, India
| | - Dharmendra Singh
- Department of Molecular Parasitology and Bioinformatics, Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Agamkuan, Patna, 800007 Bihar, India
| | - Abul H Sardar
- Department of Molecular Parasitology and Bioinformatics, Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Agamkuan, Patna, 800007 Bihar, India
| | - Ayan K Ghosh
- Department of Molecular Parasitology and Bioinformatics, Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Agamkuan, Patna, 800007 Bihar, India
| | - Pradeep Das
- Department of Molecular Parasitology and Bioinformatics, Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Agamkuan, Patna, 800007 Bihar, India
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Taylor MC, Lewis MD, Francisco AF, Wilkinson SR, Kelly JM. The Trypanosoma cruzi vitamin C dependent peroxidase confers protection against oxidative stress but is not a determinant of virulence. PLoS Negl Trop Dis 2015; 9:e0003707. [PMID: 25875298 PMCID: PMC4395405 DOI: 10.1371/journal.pntd.0003707] [Citation(s) in RCA: 27] [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: 10/06/2014] [Accepted: 03/17/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The neglected parasitic infection Chagas disease is rapidly becoming a globalised public health issue due to migration. There are only two anti-parasitic drugs available to treat this disease, benznidazole and nifurtimox. Thus it is important to identify and validate new drug targets in Trypanosoma cruzi, the causative agent. T. cruzi expresses an ER-localised ascorbate-dependent peroxidase (TcAPx). This parasite-specific enzyme has attracted interest from the perspective of targeted chemotherapy. METHODOLOGY/PRINCIPAL FINDINGS To assess the importance of TcAPx in protecting T. cruzi from oxidative stress and to determine if it is essential for virulence, we generated null mutants by targeted gene disruption. Loss of activity was associated with increased sensitivity to exogenous hydrogen peroxide, but had no effect on susceptibility to the front-line Chagas disease drug benznidazole. This suggests that increased oxidative stress in the ER does not play a significant role in its mechanism of action. Homozygous knockouts could proceed through the entire life-cycle in vitro, although they exhibited a significant decrease in their ability to infect mammalian cells. To investigate virulence, we exploited a highly sensitive bioluminescence imaging system which allows parasites to be monitored in real-time in the chronic stage of murine infections. This showed that depletion of enzyme activity had no effect on T. cruzi replication, dissemination or tissue tropism in vivo. CONCLUSIONS/SIGNIFICANCE TcAPx is not essential for parasite viability within the mammalian host, does not have a significant role in establishment or maintenance of chronic infections, and should therefore not be considered a priority for drug design.
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Affiliation(s)
- Martin C. Taylor
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
| | - Michael D. Lewis
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Amanda Fortes Francisco
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Shane R. Wilkinson
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - John M. Kelly
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Proteomic analysis of metacyclogenesis in Leishmania infantum wild-type and PTR1 null mutant. EUPA OPEN PROTEOMICS 2014. [DOI: 10.1016/j.euprot.2014.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Ascorbate peroxidase, a key molecule regulating amphotericin B resistance in clinical isolates of Leishmania donovani. Antimicrob Agents Chemother 2014; 58:6172-84. [PMID: 25114128 DOI: 10.1128/aac.02834-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amphotericin B (AmB), a polyene macrolide, is now a first-line treatment of visceral leishmaniasis cases refractory to antimonials in India. AmB relapse cases and the emergence of secondary resistance have now been reported. To understand the mechanism of AmB, differentially expressed genes in AmB resistance strains were identified by a DNA microarray and real-time reverse transcriptase PCR (RT-PCR) approach. Of the many genes functionally overexpressed in the presence of AmB, the ascorbate peroxidase gene from a resistant Leishmania donovani strain (LdAPx gene) was selected because the gene is present only in Leishmania, not in humans. Apoptosis-like cell death after exposure to AmB was investigated in a wild-type (WT) strain in which the LdAPx gene was overexpressed and in AmB-sensitive and -resistant strains. A higher percentage of apoptosis-like cell death after AmB treatment was noticed in the sensitive strain than in both the resistant isolate and the strain sensitive to LdAPx overexpression. This event is preceded by AmB-induced formation of reactive oxygen species and elevation of the cytosolic calcium level. Enhanced cytosolic calcium was found to be responsible for depolarization of the mitochondrial membrane potential and the release of cytochrome c (Cyt c) into the cytosol. The redox behavior of Cyt c showed that it has a role in the regulation of apoptosis-like cell death by activating metacaspase- and caspase-like proteins and causing concomitant nuclear alterations, as determined by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) and DNA fragmentation in the resistant strain. The present study suggests that constitutive overexpression of LdAPx in the L. donovani AmB-resistant strain prevents cells from the deleterious effect of oxidative stress, i.e., mitochondrial dysfunction and cellular death induced by AmB.
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Equbal A, Suman SS, Anwar S, Singh KP, Zaidi A, Sardar AH, Das P, Ali V. Stage-dependent expression and up-regulation of trypanothione synthetase in amphotericin B resistant Leishmania donovani. PLoS One 2014; 9:e97600. [PMID: 24901644 PMCID: PMC4046939 DOI: 10.1371/journal.pone.0097600] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 04/22/2014] [Indexed: 11/27/2022] Open
Abstract
Kinetoplastids differ from other organisms in their ability to conjugate glutathione and spermidine to form trypanothione which is involved in maintaining redox homeostasis and removal of toxic metabolites. It is also involved in drug resistance, antioxidant mechanism, and defense against cellular oxidants. Trypanothione synthetase (TryS) of thiol metabolic pathway is the sole enzyme responsible for the biosynthesis of trypanothione in Leishmania donovani. In this study, TryS gene of L. donovani (LdTryS) was cloned, expressed, and fusion protein purified with affinity column chromatography. The purified protein showed optimum enzymatic activity at pH 8.0–8.5. The TryS amino acids sequences alignment showed that all amino acids involved in catalytic and ligands binding of L. major are conserved in L. donovani. Subcellular localization using digitonin fractionation and immunoblot analysis showed that LdTryS is localized in the cytoplasm. Furthermore, RT-PCR coupled with immunoblot analysis showed that LdTryS is overexpressed in Amp B resistant and stationary phase promastigotes (∼2.0-folds) than in sensitive strain and logarithmic phase, respectively, which suggests its involvement in Amp B resistance. Also, H2O2 treatment upto 150 µM for 8 hrs leads to 2-fold increased expression of LdTryS probably to cope up with oxidative stress generated by H2O2. Therefore, this study demonstrates stage- and Amp B sensitivity-dependent expression of LdTryS in L. donovani and involvement of TryS during oxidative stress to help the parasites survival.
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Affiliation(s)
- Asif Equbal
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Shashi Shekhar Suman
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Shadab Anwar
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Krishn Pratap Singh
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Amir Zaidi
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Abul Hasan Sardar
- Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Pradeep Das
- Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Vahab Ali
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
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31
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Manhas R, Anand S, Tripathi P, Madhubala R. Deletion of Vitamin C biosynthesis enzyme, Arabino-1, 4-lactone oxidase inLeishmania donovaniresults in increased pro-inflammatory responses from host immune cells. Mol Microbiol 2014; 91:1227-39. [DOI: 10.1111/mmi.12530] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2014] [Indexed: 12/24/2022]
Affiliation(s)
- Reetika Manhas
- School of Life Sciences; Jawaharlal Nehru University; New Delhi 110067 India
| | - Sneha Anand
- School of Life Sciences; Jawaharlal Nehru University; New Delhi 110067 India
| | - Pankaj Tripathi
- School of Life Sciences; Jawaharlal Nehru University; New Delhi 110067 India
| | - Rentala Madhubala
- School of Life Sciences; Jawaharlal Nehru University; New Delhi 110067 India
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Effects of P-MAPA immunomodulator on Toll-like receptor 2, ROS, nitric oxide, MAPKp38 and IKK in PBMC and macrophages from dogs with visceral leishmaniasis. Int Immunopharmacol 2013; 18:373-8. [PMID: 24374021 DOI: 10.1016/j.intimp.2013.12.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 12/09/2013] [Indexed: 11/22/2022]
Abstract
Leishmania (L.) chagasi is the etiologic agent of visceral leishmaniasis (VL) that can be transmitted to humans and dogs. VL in Brazil represents a serious public health problem; therefore, it is important to study new alternatives to treat infected dogs. In dogs, the therapeutic arsenal against canine VL is limited. The immunomodulator protein aggregate magnesium-ammonium phospholinoleate-palmitoleate anhydride (P-MAPA) improves immunocompetence when the immune system is impaired, but its dependence on Toll-like receptors (TLRs) and the mechanisms involved in immune response remain unclear. The in vitro action of P-MAPA on the expression of TLR2 and TLR4, reactive oxygen species (ROS), nitric oxide (NO) and p38 mitogen-activated protein kinase (p38 MAPK) and IKK phosphorylation was studied in mononuclear cells from peripheral blood and macrophages from healthy and Leishmania-infected dogs. The PBMC or macrophages were isolated and cultured with different concentrations of P-MAPA (20,100 and 200 μg/ml) in a humid environment at 37°C with 5% CO(2). Observation revealed that Leishmania-infected dogs showed a decrease in TLR2 in macrophages compared with healthy dogs and in induction with P-MAPA. ROS were increased in PBMCs from Leishmania spp.-infected dogs compared with healthy dogs and P-MAPA improved ROS production. NO production was increased in culture supernatant from macrophages stimulated by P-MAPA in both healthy and Leishmania spp. infected dogs. Treatment of macrophages from healthy dogs with immunomodulatory P-MAPA induced p38 MAPK and IKK phosphorylation, suggesting signal transduction by this pathway. These findings suggest that P-MAPA has potential as a therapeutic drug in the treatment of canine visceral leishmaniasis.
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Globin-coupled heme containing oxygen sensor soluble adenylate cyclase in Leishmania prevents cell death during hypoxia. Proc Natl Acad Sci U S A 2013; 110:16790-5. [PMID: 24082109 DOI: 10.1073/pnas.1304145110] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Globin and adenylate cyclase play individually numerous crucial roles in eukaryotic organisms. Comparison of the amino acid sequences of globins and adenylate cyclase from prokaryotic to eukaryotic organisms suggests that they share an early common ancestor, even though these proteins execute different functions in these two kingdoms. The latest studies of biological signaling molecules in both prokaryotic and eukaryotic organisms have discovered a new class of heme-containing proteins that act as sensors. The protein of the globin family is still unknown in the trypanosomatid parasites, Trypanosome and Leishmania. In addition, globin-coupled heme containing adenylate cyclase is undescribed in the literature. Here we report a globin-coupled heme containing adenylate cyclase (HemAC-Lm) in the unicellular eukaryotic organism Leishmania. The protein exhibits spectral properties similar to neuroglobin and cytoglobin. Localization studies and activity measurements demonstrate that the protein is present in cytosol and oxygen directly stimulates adenylate cyclase activity in vivo and in vitro. Gene knockdown and overexpression studies suggest that O2-dependent cAMP signaling via protein kinase A plays a fundamental role in cell survival through suppression of oxidative stress under hypoxia. In addition, the enzyme-dependent cAMP generation shows a stimulatory as well as inhibitory role in cell proliferation of Leishmania promastigotes during normoxia. Our work begins to clarify how O2-dependent cAMP generation by adenylate cyclase is likely to function in cellular adaptability under various O2 tensions.
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Adak S, Pal S. Ascorbate peroxidase acts as a novel determiner of redox homeostasis in Leishmania. Antioxid Redox Signal 2013; 19:746-54. [PMID: 22703594 DOI: 10.1089/ars.2012.4745] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
SIGNIFICANCE Reactive oxygen species (ROS) are produced as natural byproducts of metabolism and respiration. While physiological levels of ROS are required for vital cellular functions (e.g., development and proliferation), a living organism is faced with constant challenges due to accumulation or overproduction of ROS throughout its life. The life cycle of Leishmania parasite has led it to confront the highly oxidizing environment in the macrophage phagosomes, necessitating ROS homeostasis and signaling as key strategies for successful survival and pathogenicity. RECENT ADVANCES Ascorbate peroxidase from Leishmania major (LmAPX) is the only heme peroxidase identified so far in Leishmania. Structural analysis and functional characterization of LmAPX have yielded interesting and novel insight on this enzyme. The protein has been found to be a hybrid of cytochrome c peroxidase and ascorbate peroxidase. This enzyme is colocalized with cytochrome c in the inner mitochondrial membrane facing the intermembrane space and shows higher activity toward cytochrome c oxidation. CRITICAL ISSUES Overexpression of LmAPX in L. major cells confers tolerance to oxidative stress-mediated cardiolipin oxidation and consequently protects cells from extensive protein damage. LmAPX-/- mutants show higher intracellular hydrogen peroxide (H₂O₂), which might signal for cellular transformation from noninfective procyclic to infective metacyclic form and ultimately apoptosis. FUTURE DIRECTIONS Manipulation of LmAPX expression has significantly added to the present understanding of the parasite's defense network against oxidative damage caused by H₂O₂. The future investigations will address more exactly the signaling pathways involved in redox homeostasis.
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Affiliation(s)
- Subrata Adak
- Division of Structural Biology and Bio-informatics, CSIR-Indian Institute of Chemical Biology, Kolkata, India.
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Abstract
SIGNIFICANCE In the single mitochondrion of protozoan trypanosomatid parasites there are several sites for the generation and elimination of reactive oxygen species (ROS), a class of molecules that exhibit a dual role in cells, either as regulatory mediators or as cytotoxic effectors. RECENT ADVANCES Formation of ROS in trypanosomatid mitochondria can be induced by various drug compounds. Importantly, it can also be triggered by specific physiologic stimuli, indicating that this phenomenon may occur in living parasites as well. Elimination of ROS in these organelles is attributed to the activity of two iron-dependent superoxide dismutases (FeSODs) and up to three different peroxidases (a cytochrome c peroxidase and two thiol peroxidases). CRITICAL ISSUES Data regarding the formation of ROS in trypanosomatid mitochondria are limited and nonsystematic. Another critical issue refers to the exact contribution of mitochondrial FeSODs and peroxidases for ROS removal, given that their antioxidant activity is not essential when abrogated individually. This suggests some level of functional overlapping or that ROS produced in mitochondria under normal conditions can be removed noncatalytically. Also still unsolved is the mechanism by which mitochondrial thiol peroxidases are regenerated to their reduced (active) form. FUTURE DIRECTIONS The production of intramitochondrial ROS under physiologic conditions and their implication in parasite biology should be further clarified. The relative importance of enzymatic versus nonenzymatic mechanisms for ROS elimination in trypanosomatid mitochondria also requires investigation. Simultaneous depletion of several redundant antioxidant enzymes and determination of noncatalytic antioxidants are possible ways to achieve this.
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Affiliation(s)
- Ana M Tomás
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
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36
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Sansom FM, Tang L, Ralton JE, Saunders EC, Naderer T, McConville MJ. Leishmania major methionine sulfoxide reductase A is required for resistance to oxidative stress and efficient replication in macrophages. PLoS One 2013; 8:e56064. [PMID: 23437085 PMCID: PMC3577802 DOI: 10.1371/journal.pone.0056064] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 01/04/2013] [Indexed: 12/25/2022] Open
Abstract
Leishmania are protozoan parasites that proliferate within the phagolysome of mammalian macrophages. While a number of anti-oxidant systems in these parasites have been shown to protect against endogenous as well as host-generated reactive oxygen species, the potential role of enzymes involved in the repair of oxidatively damaged proteins remains uncharacterized. The Leishmania spp genomes encode a single putative methionine sulfoxide reductase (MsrA) that could have a role in reducing oxidized free and proteinogenic methionine residues. A GFP-fusion of L. major MsrA was shown to have a cytoplasmic localization by immunofluorescence microscopy and subcellular fractionation. An L. major msrA null mutant, generated by targeted replacement of both chromosomal allelles, was viable in rich medium but was unable to reduce exogenous methionine sulfoxide when cultivated in the presence of this amino acid, indicating that msrA encodes a functional MsrA. The ΔmsrA mutant exhibited increased sensitivity to H2O2 compared to wild type parasites and was unable to proliferate normally in macrophages. Wild type sensitivity to H2O2 and infectivity in macrophages was restored by complementation of the mutant with a plasmid encoding MsrA. Unexpectedly, the ΔmsrA mutant was able to induce normal lesions in susceptible BALB/c indicating that this protein is not essential for pathogenesis in vivo. Our results suggest that Leishmania MsrA contributes to the anti-oxidative defences of these parasites, but that complementary oxidative defence mechansims are up-regulated in lesion amastigotes.
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Affiliation(s)
- Fiona M. Sansom
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
- Faculty of Veterinary Science, University of Melbourne, Parkville, Victoria, Australia
| | - Leonie Tang
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
| | - Julie E. Ralton
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
| | - Eleanor C. Saunders
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
| | - Thomas Naderer
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
| | - Malcolm J. McConville
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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Bose M, Saha R, Sen Santara S, Mukherjee S, Roy J, Adak S. Protection against peroxynitrite by pseudoperoxidase from Leishmania major. Free Radic Biol Med 2012; 53:1819-28. [PMID: 22985938 DOI: 10.1016/j.freeradbiomed.2012.08.583] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 08/23/2012] [Accepted: 08/23/2012] [Indexed: 11/22/2022]
Abstract
Heme proteins share the ability to detoxify reactive nitrogen intermediates (NO and peroxynitrite). But, to date, no heme-containing enzymatic defense against toxic reactive nitrogen intermediates has been discovered in Leishmania species. We have cloned, expressed, and characterized a pseudoperoxidase from Leishmania major (LmPP) that is capable of detoxifying peroxynitrite (ONOO(-)). Optical, EPR, and resonance Raman spectral studies demonstrate that ONOO(-) can rapidly convert the six-coordinate ferric low-spin to a ferric high-spin form at neutral pH. Western blotting and immunofluorescence studies with anti-LmPP antibody show that the mature enzyme is located at the plasma membrane of amastigotes and is expressed eightfold higher in amastigotes compared to promastigotes. Moreover, to further investigate its exact physiological role in Leishmania, we have created LmPP-knockout mutants by gene replacement in L. major strains. IC(50) values for exogenously added H(2)O(2) or 3-morpholinosydnonimine (SIN1) show that deletion of LmPP in L. major renders the cell more susceptible to SIN1. The null mutant cells exhibit a marked decrease in virulence on infection with activated macrophages as well as inoculation into BALB/c mice. Collectively, these data provide strong evidence that LmPP plays an important role in the enzymatic defense against ONOO(-) within macrophages.
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Affiliation(s)
- Moumita Bose
- Division of Structural Biology and Bio-informatics, Indian Institute of Chemical Biology, Kolkata, India
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Mukherjee S, Sen Santara S, Das S, Bose M, Roy J, Adak S. NAD(P)H cytochrome b5 oxidoreductase deficiency in Leishmania major results in impaired linoleate synthesis followed by increased oxidative stress and cell death. J Biol Chem 2012; 287:34992-35003. [PMID: 22923617 DOI: 10.1074/jbc.m112.389338] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
NAD(P)H cytochrome b(5) oxidoreductase (Ncb5or), comprising cytochrome b(5) and cytochrome b(5) reductase domains, is widely distributed in eukaryotic organisms. Although Ncb5or plays a crucial role in lipid metabolism of mice, so far no Ncb5or gene has been reported in the unicellular parasitic protozoa Leishmania species. We have cloned, expressed, and characterized Ncb5or gene from Leishmania major. Steady state catalysis and spectral studies show that NADH can quickly reduce the ferric state of the enzyme to the ferrous state and is able to donate an electron(s) to external acceptors. To elucidate its exact physiological role in Leishmania, we attempted to create NAD(P)H cytochrome b(5) oxidoreductase from L. major (LmNcb5or) knock-out mutants by targeted gene replacement technique. A free fatty acid profile in knock-out (KO) cells reveals marked deficiency in linoleate and linolenate when compared with wild type (WT) or overexpressing cells. KO culture has a higher percentage of dead cells compared with both WT and overexpressing cells. Increased O(2) uptake, uncoupling and ATP synthesis, and loss of mitochondrial membrane potential are evident in KO cells. Flow cytometric analysis reveals the presence of a higher concentration of intracellular H(2)O(2), indicative of increased oxidative stress in parasites lacking LmNcb5or. Cell death is significantly reduced when the KO cells are pretreated with BSA bound linoleate. Real time PCR studies demonstrate a higher Δ12 desaturase, superoxide dismutase, and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA with a concomitant fall in Δ9 desaturase mRNA expression in LmNcb5or null cell line. Together these findings suggest that decreased linoleate synthesis, and increased oxidative stress and apoptosis are the major consequences of LmNcb5or deficiency in Leishmania.
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Affiliation(s)
- Supratim Mukherjee
- Division of Structural Biology and Bioinformatics, Council of Scientific and Industrial Research, Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700 032, India
| | - Sumit Sen Santara
- Division of Structural Biology and Bioinformatics, Council of Scientific and Industrial Research, Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700 032, India
| | - Shantanabha Das
- Division of Structural Biology and Bioinformatics, Council of Scientific and Industrial Research, Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700 032, India
| | - Moumita Bose
- Division of Structural Biology and Bioinformatics, Council of Scientific and Industrial Research, Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700 032, India
| | - Jayasree Roy
- Division of Structural Biology and Bioinformatics, Council of Scientific and Industrial Research, Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700 032, India
| | - Subrata Adak
- Division of Structural Biology and Bioinformatics, Council of Scientific and Industrial Research, Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700 032, India.
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Abstract
SIGNIFICANCE Parasitic infections continue to be a major problem for global human health. Vaccines are practically not available and chemotherapy is highly unsatisfactory. One approach toward a novel antiparasitic drug development is to unravel pathways that may be suited as future targets. Parasitic organisms show a remarkable diversity with respect to the nature and functions of their main low-molecular-mass antioxidants and many of them developed pathways that do not have a counterpart in their mammalian hosts. RECENT ADVANCES Work of the last years disclosed the individual antioxidants employed by parasites and their distinct pathways. Entamoeba, Trichomonas, and Giardia directly use cysteine as main low-molecular-mass thiol but have divergent cysteine metabolisms. Malarial parasites rely exclusively on cysteine uptake and generate glutathione (GSH) as main free thiol as do metazoan parasites. Trypanosomes and Leishmania have a unique trypanothione-based thiol metabolism but employ individual mechanisms for their cysteine supply. In addition, some trypanosomatids synthesize ovothiol A and/or ascorbate. Various essential parasite enzymes such as trypanothione synthetase and trypanothione reductase in Trypanosomatids and the Schistosoma thioredoxin GSH reductase are currently intensively explored as drug target molecules. CRITICAL ISSUES Essentiality is a prerequisite but not a sufficient property of an enzyme to become a suited drug target. The availability of an appropriate in vivo screening system and many other factors are equally important. FUTURE DIRECTIONS The current organism-wide RNA-interference and proteome analyses are supposed to reveal many more interesting candidates for future drug development approaches directed against the parasite antioxidant defense systems.
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Pal S, Yadav RK, Adak S. Role of K(+) binding residues in stabilization of heme spin state of Leishmania major peroxidase. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1824:1002-1007. [PMID: 22617686 DOI: 10.1016/j.bbapap.2012.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 05/10/2012] [Accepted: 05/11/2012] [Indexed: 06/01/2023]
Abstract
The endogenous cation in peroxidases may contribute to the type of heme coordination. Here a series of ferric and ferrous derivatives of wild-type Leishmania major peroxidase (LmP) and of engineered K(+) site mutants of LmP, lacking potassium cation binding site, has been examined by electronic absorption spectroscopy at 25°C. Using UV-visible spectrophotometry, we show that the removal of K(+) binding site causes substantial changes in spin states of both the ferric and ferrous forms. The spectral changes are interpreted to be, most likely, due to the formation of a bis-histidine coordination structure in both the ferric and ferrous oxidation states at neutral pH 7.0. Stopped flow spectrophotometric techniques revealed that characteristics of Compound I were not observed in the K(+) site double mutants in the presence of H(2)O(2). Similarly electron donor oxidation rate was two orders less for the K(+) site double mutants compared to the wild type. These data show that K(+) functions in preserving the protein structure in the heme surroundings as well as the spin state of the heme iron, in favor of the enzymatically active form of LmP.
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Affiliation(s)
- Swati Pal
- CSIR-Indian Institute of Chemical Biology, Kolkata, India
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41
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Nogueira FB, Rodrigues JFA, Correa MMS, Ruiz JC, Romanha AJ, Murta SMF. The level of ascorbate peroxidase is enhanced in benznidazole-resistant populations of Trypanosoma cruzi and its expression is modulated by stress generated by hydrogen peroxide. Mem Inst Oswaldo Cruz 2012; 107:494-502. [DOI: 10.1590/s0074-02762012000400009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Accepted: 12/14/2011] [Indexed: 11/22/2022] Open
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Jasion VS, Poulos TL. Leishmania major peroxidase is a cytochrome c peroxidase. Biochemistry 2012; 51:2453-60. [PMID: 22372542 DOI: 10.1021/bi300169x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Leishmania major peroxidase (LmP) exhibits both ascorbate and cytochrome c peroxidase activities. Our previous results illustrated that LmP has a much higher activity against horse heart cytochrome c than ascorbate, suggesting that cytochrome c may be the biologically important substrate. To elucidate the biological function of LmP, we have recombinantly expressed, purified, and determined the 2.08 Å crystal structure of L. major cytochrome c (LmCytc). Like other types of cytochrome c, LmCytc has an electropositive surface surrounding the exposed heme edge that serves as the site of docking with redox partners. Kinetic assays performed with LmCytc and LmP show that LmCytc is a much better substrate for LmP than horse heart cytochrome c. Furthermore, unlike the well-studied yeast system, the reaction follows classic Michaelis-Menten kinetics and is sensitive to an increasing ionic strength. Using the yeast cocrystal as a control, protein-protein docking was performed using Rosetta to develop a model for the binding of LmP and LmCytc. These results suggest that the biological function of LmP is to act as a cytochrome c peroxidase.
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Affiliation(s)
- Victoria S Jasion
- Departments of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical Sciences, University of California, Irvine, California 92697-3900, United States
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Castro H, Teixeira F, Romao S, Santos M, Cruz T, Flórido M, Appelberg R, Oliveira P, Ferreira-da-Silva F, Tomás AM. Leishmania mitochondrial peroxiredoxin plays a crucial peroxidase-unrelated role during infection: insight into its novel chaperone activity. PLoS Pathog 2011; 7:e1002325. [PMID: 22046130 PMCID: PMC3203189 DOI: 10.1371/journal.ppat.1002325] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 09/02/2011] [Indexed: 11/24/2022] Open
Abstract
Two-cysteine peroxiredoxins are ubiquitous peroxidases that play various functions in cells. In Leishmania and related trypanosomatids, which lack catalase and selenium-glutathione peroxidases, the discovery of this family of enzymes provided the molecular basis for peroxide removal in these organisms. In this report the functional relevance of one of such enzymes, the mitochondrial 2-Cys peroxiredoxin (mTXNPx), was investigated along the Leishmania infantum life cycle. mTXNPx null mutants (mtxnpx(-)) produced by a gene replacement strategy, while indistinguishable from wild type promastigotes, were found unable to thrive in a murine model of infection. Unexpectedly, however, the avirulent phenotype of mtxnpx(-) was not due to lack of the peroxidase activity of mTXNPx as these behaved like controls when exposed to oxidants added exogenously or generated by macrophages during phagocytosis ex vivo. In line with this, mtxnpx(-) were also avirulent when inoculated into murine hosts unable to mount an effective oxidative phagocyte response (B6.p47(phox-/-) and B6.RAG2(-/-) IFN-γ(-/-) mice). Definitive conclusion that the peroxidase activity of mTXNPx is not required for parasite survival in mice was obtained by showing that a peroxidase-inactive version of this protein was competent in rescuing the non-infective phenotype of mtxnpx(-). A novel function is thus proposed for mTXNPx, that of a molecular chaperone, which may explain the impaired infectivity of the null mutants. This premise is based on the observation that the enzyme is able to suppress the thermal aggregation of citrate synthase in vitro. Also, mtxnpx(-) were more sensitive than controls to a temperature shift from 25°C to 37°C, a phenotype reminiscent of organisms lacking specific chaperone genes. Collectively, the findings reported here change the paradigm which regards all trypanosomatid 2-Cys peroxiredoxins as peroxide-eliminating devices. Moreover, they demonstrate, for the first time, that these 2-Cys peroxiredoxins can be determinant for pathogenicity independently of their peroxidase activity.
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Affiliation(s)
- Helena Castro
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Filipa Teixeira
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Susana Romao
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Mariana Santos
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Tânia Cruz
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Manuela Flórido
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Rui Appelberg
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Pedro Oliveira
- ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | | | - Ana M. Tomás
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
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Yadav RK, Pal S, Dolai S, Adak S. Role of proximal methionine residues in Leishmania major peroxidase. Arch Biochem Biophys 2011; 515:21-7. [PMID: 21893024 DOI: 10.1016/j.abb.2011.08.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 08/19/2011] [Accepted: 08/20/2011] [Indexed: 10/17/2022]
Abstract
The active site architecture of Leishmania major peroxidase (LmP) is very similar with both cytochrome c peroxidase and ascorbate peroxidase. We utilized point mutagenesis to investigate if the conserved proximal methionine residues (Met248 and Met249) in LmP help in controlling catalysis. Steady-state kinetics of methionine mutants shows that ferrocytochrome c oxidation is <2% of wild type levels without affecting the second order rate constant of first phase of Compound I formation, while the activity toward a small molecule substrate, guaiacol or iodide, increases. Our diode array stopped-flow spectral studies show that the porphyrin π-cation radical of Compound I in mutant LmP is more stable than wild type enzyme. These results suggest that the electronegative sulfur atoms of the proximal pocket are critical factors for controlling the location of a stable Compound I radical in heme peroxidases and are important in the oxidation of ferrocytochrome c.
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Affiliation(s)
- Rajesh K Yadav
- Division of Structural Biology and Bio-informatics, Indian Institute of Chemical Biology, Council of Scientific and Industrial Research, 4, Raja S.C. Mullick Road, Kolkata, India
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Diechtierow M, Krauth-Siegel RL. A tryparedoxin-dependent peroxidase protects African trypanosomes from membrane damage. Free Radic Biol Med 2011; 51:856-68. [PMID: 21640819 DOI: 10.1016/j.freeradbiomed.2011.05.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 05/11/2011] [Accepted: 05/11/2011] [Indexed: 01/18/2023]
Abstract
Hydroperoxide detoxification in African trypanosomes is achieved by 2-Cys-peroxiredoxin (TXNPx)- and non-selenium glutathione peroxidase (Px)-type enzymes which both obtain their reducing equivalents from the unique trypanothione/tryparedoxin system. Previous RNA interference approaches revealed that the cytosolic TXNPx and the Px-type enzymes are essential for Trypanosoma brucei. Because of partially overlapping in vitro substrate specificities and subcellular localisation the physiological function of the individual enzymes was not yet clear. As shown here, TXNPx and Px are expressed at comparable levels and in their active reduced state. Px-overexpressing parasites were less sensitive toward linoleic acid hydroperoxide but not hydrogen peroxide. Kinetic studies confirmed that Px-but not TXNPx-reduces lipophilic hydroperoxides including phospholipids with high efficiency. Most interestingly, the severe proliferation defect of Px-depleted bloodstream cells could be rescued by Trolox, but not by hydrophilic antioxidants, in the medium. This allowed us to knock-out the three Px genes individually and thus to distinguish their in vivo role. Deletion of the cytosolic Px I and II resulted in extremely fast membrane peroxidation followed by cell lysis. Cells lacking specifically the mitochondrial Px III showed a transient growth retardation and cardiolipin peroxidation but adapted within 24h to normal proliferation.
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Affiliation(s)
- Michael Diechtierow
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
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Van Assche T, Deschacht M, da Luz RAI, Maes L, Cos P. Leishmania-macrophage interactions: insights into the redox biology. Free Radic Biol Med 2011; 51:337-51. [PMID: 21620959 DOI: 10.1016/j.freeradbiomed.2011.05.011] [Citation(s) in RCA: 152] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 04/24/2011] [Accepted: 05/07/2011] [Indexed: 11/19/2022]
Abstract
Leishmaniasis is a neglected tropical disease that affects about 350 million individuals worldwide. The protozoan parasite has a relatively simple life cycle with two principal stages: the flagellated mobile promastigote living in the gut of the sandfly vector and the intracellular amastigote within phagolysosomal vesicles of the vertebrate host macrophage. This review presents a state-of-the-art overview of the redox biology at the parasite-macrophage interface. Although Leishmania species are susceptible in vitro to exogenous superoxide radical, hydrogen peroxide, nitric oxide, and peroxynitrite, they manage to survive the endogenous oxidative burst during phagocytosis and the subsequent elevated nitric oxide production in the macrophage. The parasite adopts various defense mechanisms to cope with oxidative stress: the lipophosphoglycan membrane decreases superoxide radical production by inhibiting NADPH oxidase assembly and the parasite also protects itself by expressing antioxidant enzymes and proteins. Some of these enzymes could be considered potential drug targets because they are not expressed in mammals. In respect to antileishmanial therapy, the effects of current drugs on parasite-macrophage redox biology and its involvement in the development of drug resistance and treatment failure are presented.
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Affiliation(s)
- Tim Van Assche
- Laboratory of Microbiology Parasitology, and Hygiene, University of Antwerp, B-2020 Antwerp, Belgium
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Dolai S, Pal S, Yadav RK, Adak S. Endoplasmic reticulum stress-induced apoptosis in Leishmania through Ca2+-dependent and caspase-independent mechanism. J Biol Chem 2011; 286:13638-46. [PMID: 21330370 DOI: 10.1074/jbc.m110.201889] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Numerous reports have shown that mitochondrial dysfunctions play a major role in apoptosis of Leishmania parasites, but the endoplasmic reticulum (ER) stress-induced apoptosis in Leishmania remains largely unknown. In this study, we investigate ER stress-induced apoptotic pathways in Leishmania major using tunicamycin as an ER stress inducer. ER stress activates the expression of ER-localized chaperone protein BIP/GRP78 (binding protein/identical to the 78-kDa glucose-regulated protein) with concomitant generation of intracellular reactive oxygen species. Upon exposure to ER stress, the elevation of cytosolic Ca(2+) level is observed due to release of Ca(2+) from internal stores. Increase in cytosolic Ca(2+) causes mitochondrial membrane potential depolarization and ATP loss as ablation of Ca(2+) by blocking voltage-gated cation channels with verapamil preserves mitochondrial membrane potential and cellular ATP content. Furthermore, ER stress-induced reactive oxygen species (ROS)-dependent release of cytochrome c and endonuclease G from mitochondria to cytosol and subsequent translocation of endonuclease G to nucleus are observed. Inhibition of caspase-like proteases with the caspase inhibitor benzyloxycarbonyl-VAD-fluoromethyl ketone or metacaspase inhibitor antipain does not prevent nuclear DNA fragmentation and phosphatidylserine exposure. Conversely, significant protection in tunicamycin-induced DNA degradation and phosphatidylserine exposure was achieved by either pretreatment of antioxidants (N-acetyl-L-cysteine, GSH, and L-cysteine), chemical chaperone (4-phenylbutyric acid), or addition of Ca(2+) chelator (1,2-bis(2-aminophenoxy)ethane-N,N,N,N-tetraacetic acid-acetoxymethyl ester). Taken together, these data strongly demonstrate that ER stress-induced apoptosis in L. major is dependent on ROS and Ca(2+)-induced mitochondrial toxicity but independent of caspase-like proteases.
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Affiliation(s)
- Subhankar Dolai
- Division of Structural Biology and Bio-informatics, Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata-700 032, India
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Mitochondrial redox metabolism in trypanosomatids is independent of tryparedoxin activity. PLoS One 2010; 5:e12607. [PMID: 20838623 PMCID: PMC2935891 DOI: 10.1371/journal.pone.0012607] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Accepted: 08/13/2010] [Indexed: 01/07/2023] Open
Abstract
Tryparedoxins (TXNs) are oxidoreductases unique to trypanosomatids (including Leishmania and Trypanosoma parasites) that transfer reducing equivalents from trypanothione, the major thiol in these organisms, to sulfur-dependent peroxidases and other dithiol proteins. The existence of a TXN within the mitochondrion of trypanosomatids, capable of driving crucial redox pathways, is considered a requisite for normal parasite metabolism. Here this concept is shown not to apply to Leishmania. First, removal of the Leishmania infantum mitochondrial TXN (LiTXN2) by gene-targeting, had no significant effect on parasite survival, even in the context of an animal infection. Second, evidence is presented that no other TXN is capable of replacing LiTXN2. In fact, although a candidate substitute for LiTXN2 (LiTXN3) was found in the genome of L. infantum, this was shown in biochemical assays to be poorly reduced by trypanothione and to be unable to reduce sulfur-containing peroxidases. Definitive conclusion that LiTXN3 cannot directly reduce proteins located within inner mitochondrial compartments was provided by analysis of its subcellular localization and membrane topology, which revealed that LiTXN3 is a tail-anchored (TA) mitochondrial outer membrane protein presenting, as characteristic of TA proteins, its N-terminal end (containing the redox-active domain) exposed to the cytosol. This manuscript further proposes the separation of trypanosomatid TXN sequences into two classes and this is supported by phylogenetic analysis: i) class I, encoding active TXNs, and ii) class II, coding for TA proteins unlikely to function as TXNs. Trypanosoma possess only two TXNs, one belonging to class I (which is cytosolic) and the other to class II. Thus, as demonstrated for Leishmania, the mitochondrial redox metabolism in Trypanosoma may also be independent of TXN activity. The major implication of these findings is that mitochondrial functions previously thought to depend on the provision of electrons by a TXN enzyme must proceed differently.
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Poulos TL. Thirty years of heme peroxidase structural biology. Arch Biochem Biophys 2010; 500:3-12. [PMID: 20206121 PMCID: PMC3202974 DOI: 10.1016/j.abb.2010.02.008] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 02/18/2010] [Accepted: 02/20/2010] [Indexed: 10/19/2022]
Abstract
The following is a brief review of peroxidase structural biology since the initial structure determination of cytochrome c peroxidase (CCP) 30 years ago. An emphasis will be placed on what CCP has taught us about peroxidase mechanisms, especially Compound I formation and electron transfer.
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Affiliation(s)
- Thomas L Poulos
- Departments of Molecular Biology & Biochemistry, Chemistry, and Pharmaceutical Sciences, University of California-Irvine, Irvine, CA 92697-3900, USA.
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Frequency of drug resistance gene amplification in clinical leishmania strains. Int J Microbiol 2010; 2010. [PMID: 20706666 PMCID: PMC2913627 DOI: 10.1155/2010/819060] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 06/04/2010] [Accepted: 06/13/2010] [Indexed: 11/29/2022] Open
Abstract
Experimental studies about Leishmania resistance to metal and antifolates have pointed out that gene amplification is one of the main mechanisms of drug detoxification. Amplified genes code for adenosine triphosphate-dependent transporters (multidrug resistance and P-glycoproteins P), enzymes involved in trypanothione pathway, particularly gamma glutamyl cysteine synthase, and others involved in folates metabolism, such as dihydrofolate reductase and pterine reductase. The aim of this study was to detect and quantify the amplification of these genes in clinical strains of visceral leishmaniasis agents: Leishmania infantum, L. donovani, and L. archibaldi. Relative quantification experiments by means of real-time polymerase chain reaction showed that multidrug resistance gene amplification is the more frequent event. For P-glycoproteins P and dihydrofolate reductase genes, level of amplification was comparable to the level observed after in vitro selection of resistant clones. Gene amplification is therefore a common phenomenon in wild strains concurring to Leishmania genomic plasticity. This finding, which corroborates results of experimental studies, supports a better understanding of metal resistance selection and spreading in endemic areas.
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