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Vargas-Villanueva JR, Gutiérrez-Gutiérrez F, Garza-Ontiveros M, Nery-Flores SD, Campos-Múzquiz LG, Vazquez-Obregón D, Rodriguez-Herrera R, Palomo-Ligas L. Tubulin as a potential molecular target for resveratrol in Giardia lamblia trophozoites, in vitro and in silico approaches. Acta Trop 2023; 248:107026. [PMID: 37722447 DOI: 10.1016/j.actatropica.2023.107026] [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: 06/05/2023] [Revised: 09/14/2023] [Accepted: 09/15/2023] [Indexed: 09/20/2023]
Abstract
Giardia lamblia is a globally distributed protozoan parasite that causes intestinal disease. Recently, there is an increase in refractory cases of giardiasis to chemotherapeutic agents, and drugs available cause side effects that may limit its use or cause therapeutic non-compliance. Therefore, search for alternative and less harmful drugs to treat giardiasis is an important task. In this sense, resveratrol (RSV) is a polyphenol with a wide range of pharmacological effects such as antimicrobial, anticarcinogenic and antioxidant. The aim of this study was to evaluate the effects of RSV on Giardia lamblia trophozoites in vitro and in silico, focusing on tubulin affectation, a major protein of the Giardia cytoskeleton which participates in relevant processes for cell survival. In vitro determinations showed that RSV inhibits parasite growth and adherence, causes morphological changes, and induces apoptosis-like cell death through tubulin alterations demonstrated by immunolocalization and Western blot assays. Bioinformatic analysis by molecular docking suggested that RSV binds to Giardia tubulin interface heterodimer, sharing binding residues to those reported with depolymerization inhibitors. These findings suggest that RSV affects microtubular dynamics and make it an interesting compound to study for its safety and antigiardiasic potential.
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Affiliation(s)
| | - Filiberto Gutiérrez-Gutiérrez
- Departamento de Farmacobiología, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Guadalajara, Jalisco, 44430, Mexico; División de Salud, Centro Universitario de Tlajomulco, Universidad de Guadalajara, Tlajomulco de Zúñiga, Jalisco, 45641, Mexico
| | - Mariana Garza-Ontiveros
- Facultad de Ciencias Químicas. Universidad Autonoma de Coahuila. Unidad Saltillo. Saltillo, Coahuila, 25280, Mexico
| | - Sendar Daniel Nery-Flores
- Facultad de Ciencias Químicas. Universidad Autonoma de Coahuila. Unidad Saltillo. Saltillo, Coahuila, 25280, Mexico
| | | | - Dagoberto Vazquez-Obregón
- Tecnológico Nacional de México/ Instituto tecnológico de Saltillo. Departamento de Metal Mecánica. Saltillo, Coahuila 25280, Mexico
| | - Raul Rodriguez-Herrera
- Facultad de Ciencias Químicas. Universidad Autonoma de Coahuila. Unidad Saltillo. Saltillo, Coahuila, 25280, Mexico
| | - Lissethe Palomo-Ligas
- Facultad de Ciencias Químicas. Universidad Autonoma de Coahuila. Unidad Saltillo. Saltillo, Coahuila, 25280, Mexico.
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Benchimol M, Gadelha AP, de Souza W. Ultrastructural Alterations of the Human Pathogen Giardia intestinalis after Drug Treatment. Pathogens 2023; 12:810. [PMID: 37375500 DOI: 10.3390/pathogens12060810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/04/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
This review presents the main cell characteristics altered after in vitro incubation of the parasite with commercial drugs used to treat the disease caused by Giardia intestinalis. This important intestinal parasite primarily causes diarrhea in children. Metronidazole and albendazole are the primary compounds used in therapy against Giardia intestinalis. However, they provoke significant side effects, and some strains have developed resistance to metronidazole. Benzimidazole carbamates, such as albendazole and mebendazole, have shown the best activity against Giardia. Despite their in vitro efficacy, clinical treatment with benzimidazoles has yielded conflicting results, demonstrating lower cure rates. Recently, nitazoxanide has been suggested as an alternative to these drugs. Therefore, to enhance the quality of chemotherapy against this parasite, it is important to invest in developing other compounds that can interfere with key steps of metabolic pathways or cell structures and organelles. For example, Giardia exhibits a unique cell structure called the ventral disc, which is crucial for host adhesion and pathogenicity. Thus, drugs that can disrupt the adhesion process hold promise for future therapy against Giardia. Additionally, this review discusses new drugs and strategies that can be employed, as well as suggestions for developing novel drugs to control the infection caused by this parasite.
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Affiliation(s)
- Marlene Benchimol
- BIOTRANS-CAXIAS, Universidade do Grande Rio. UNIGRANRIO, Rio de Janeiro 96200-000, Brazil
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens e Centro Nacional de Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Ana Paula Gadelha
- Diretoria de Metrologia Científica, Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), Rio de Janeiro 25259-020, Brazil
| | - Wanderley de Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens e Centro Nacional de Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
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3
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Benchimol M, Gadelha AP, de Souza W. Unusual Cell Structures and Organelles in Giardia intestinalis and Trichomonas vaginalis Are Potential Drug Targets. Microorganisms 2022; 10:2176. [PMID: 36363768 PMCID: PMC9698047 DOI: 10.3390/microorganisms10112176] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 09/29/2023] Open
Abstract
This review presents the main cell organelles and structures of two important protist parasites, Giardia intestinalis, and Trichomonas vaginalis; many are unusual and are not found in other eukaryotic cells, thus could be good candidates for new drug targets aimed at improvement of the chemotherapy of diseases caused by these eukaryotic protists. For example, in Giardia, the ventral disc is a specific structure to this parasite and is fundamental for the adhesion and pathogenicity to the host. In Trichomonas, the hydrogenosome, a double membrane-bounded organelle that produces ATP, also can be a good target. Other structures include mitosomes, ribosomes, and proteasomes. Metronidazole is the most frequent compound used to kill many anaerobic organisms, including Giardia and Trichomonas. It enters the cell by passive diffusion and needs to find a highly reductive environment to be reduced to the nitro radicals to be active. However, it provokes several side effects, and some strains present metronidazole resistance. Therefore, to improve the quality of the chemotherapy against parasitic protozoa is important to invest in the development of highly specific compounds that interfere with key steps of essential metabolic pathways or in the functional macromolecular complexes which are most often associated with cell structures and organelles.
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Affiliation(s)
- Marlene Benchimol
- Laboratorio de Ultraestrutura Celular Hertha Meyer, Centro de Ciêcias da Saúde, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Cidade Universitaria, Rio de Janeiro 96200-000, Brazil
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens e Centro Nacional de Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Ana Paula Gadelha
- Diretoria de Metrologia Aplicada as Ciências da Vida, Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), Rio de Janeiro 25250-020, Brazil
| | - Wanderley de Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens e Centro Nacional de Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
- CMABio, Escola Superior de Saúde, Universidade do Estado do Amazonas-UEA, Manaus 69850-000, Brazil
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Oliveira RVF, de Souza W, Vögerl K, Bracher F, Benchimol M, Gadelha APR. In vitro effects of the 4-[(10H-phenothiazin-10-yl)methyl]-N-hydroxybenzamide on Giardia intestinalis trophozoites. Acta Trop 2022; 232:106484. [PMID: 35483428 DOI: 10.1016/j.actatropica.2022.106484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 11/01/2022]
Abstract
Giardiasis is an intestinal disease caused by the parasite protozoan Giardia intestinalis. For more than five decades, the treatment of this disease has been based on compounds such as nitroimidazoles and benzimidazoles. The parasite's adverse effects and therapeutic failure are largely recognized. Therefore, it is necessary to develop new forms of chemotherapy treatment against giardiasis. Lysine deacetylases (KDACs), which remove an acetyl group from lysine residues in histone and non-histone proteins as tubulin, are found in the Giardia genome and can become an interesting option for giardiasis treatment. In the present study, we evaluated the effects of 4-[(10H-phenothiazin-10-yl)methyl]-N-hydroxybenzamide, a new class I/II KDAC inhibitor, on G. intestinalis growth, cytoskeleton, and ultrastructure organization. This compound decreased parasite proliferation and viability and displayed an IC50 value of 179 nM. Scanning electron microscopy revealed the presence of protrusions on the cell surface after treatment. In addition, the vacuoles containing concentric membranous lamella and glycogen granules were observed in treated trophozoites. The cell membrane appeared deformed just above these vacuoles. Alterations on the microtubular cytoskeleton of the parasite were not observed after drug exposure. The number of diving cells with incomplete cytokinesis increased after treatment, indicating that the compound can interfere in the late steps of cell division. Our results indicate that 4-[(10H-phenothiazin-10-yl)methyl]-N-hydroxybenzamide should be explored to develop new therapeutic compounds for treating giardiasis.
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Hennessey KM, Alas GCM, Rogiers I, Li R, Merritt EA, Paredez AR. Nek8445, a protein kinase required for microtubule regulation and cytokinesis in Giardia lamblia. Mol Biol Cell 2020; 31:1611-1622. [PMID: 32459558 PMCID: PMC7521801 DOI: 10.1091/mbc.e19-07-0406] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Giardia has 198 Nek kinases whereas humans have only 11. Giardia has a complex microtubule cytoskeleton that includes eight flagella and several unique microtubule arrays that are utilized for parasite attachment and facilitation of rapid mitosis and cytokinesis. The need to regulate these structures may explain the parallel expansion of the number of Nek family kinases. Here we use live and fixed cell imaging to uncover the role of Nek8445 in regulating Giardia cell division. We demonstrate that Nek8445 localization is cell cycle regulated and this kinase has a role in regulating overall microtubule organization. Nek8445 depletion results in short flagella, aberrant ventral disk organization, loss of the funis, defective axoneme exit, and altered cell shape. The axoneme exit defect is specific to the caudal axonemes, which exit from the posterior of the cell, and this defect correlates with rounding of the cell posterior and loss of the funis. Our findings implicate a role for the funis in establishing Giardia’s cell shape and guiding axoneme docking. On a broader scale our results support the emerging view that Nek family kinases have a general role in regulating microtubule organization.
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Affiliation(s)
| | - Germain C M Alas
- Department of Biology, University of Washington, Seattle, WA 98195
| | - Ilse Rogiers
- Department of Biochemistry, University of Washington, Seattle, WA 98195
| | - Renyu Li
- Department of Biology, University of Washington, Seattle, WA 98195
| | - Ethan A Merritt
- Department of Biochemistry, University of Washington, Seattle, WA 98195
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Abstract
Giardia intestinalis, the causative agent of giardiasis, has complex cytoskeleton organization with structures involved in motility, adhesion, cell division, and cell differentiation. Microtubules are key components of the cytoskeleton and are the main elements of the ventral disc, median body, funis, in addition to four pairs of flagella. These cytoskeletal elements are basically stable microtubule arrangements. Although tubulins are the main proteins of these elements, molecular and biochemical analyses of Giardia trophozoites have revealed the presence of several new and not yet characterized proteins in these structures, which may contribute to their nanoarchitecture (mainly in the ventral disc). Despite these findings, morphological data are still required for understanding the organization and biogenesis of the cytoskeletal structures. In the study of this complex and specialized network of filaments in Giardia, two distinct and complementary approaches have been used in recent years: (a) transmission electron microscopy tomography of conventionally processed as well as cryo-fixed samples and (b) high-resolution scanning electron microscopy and helium ion microscopy in combination with new plasma membrane extraction protocols. In this review we include the most recent studies that have allowed better understanding of new Giardia components and their association with other filamentous structures of this parasite, thus providing new insights in the role of the cytoskeletal structures and their function in Giardia trophozoites.
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Rivera Fernández N, Mondragón Castelán M, González Pozos S, Ramírez Flores CJ, Mondragón González R, Gómez de León CT, Castro Elizalde KN, Marrero Ponce Y, Arán VJ, Martins Alho MA, Mondragón Flores R. A new type of quinoxalinone derivatives affects viability, invasion, and intracellular growth of Toxoplasma gondii tachyzoites in vitro. Parasitol Res 2016; 115:2081-96. [PMID: 26888289 DOI: 10.1007/s00436-016-4953-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/04/2016] [Indexed: 12/11/2022]
Abstract
Quinoxalinone derivatives, identified as VAM2 compounds (7-nitroquinoxalin-2-ones), were evaluated against Toxoplasma gondii tachyzoites of the RH strain. The VAM2 compounds were previously synthesized based on the design obtained from an in silico prediction with the software TOMOCOMD-CARDD. From the ten VAM2 drugs tested, several showed a deleterious effect on tachyzoites. However, VAM2-2 showed the highest toxoplasmicidal activity generating a remarkable decrease in tachyzoite viability (in about 91 %) and a minimal alteration in the host cell. An evident inhibition of host cell invasion by tachyzoites previously treated with VAM2-2 was observed in a dose-dependent manner. In addition, remarkable alterations were observed in the pellicle parasite, such as swelling, roughness, and blebbing. Toxoplasma motility was inhibited, and subpellicular cytoskeleton integrity was altered, inducing a release of its components to the soluble fraction. VAM2-2 showed a clear and specific deleterious effect on tachyzoites viability, structural integrity, and invasive capabilities with limited effects in host cells morphology and viability. VAM2-2 minimum inhibitory concentration (MIC50) was determined as 3.3 μM ± 1.8. Effects of quinoxalinone derivatives on T. gondii provide the basis for a future therapeutical alternative in the treatment of toxoplasmosis.
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Affiliation(s)
- Norma Rivera Fernández
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Coyoacán 04510, DF, México
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN No 2508 Delegación Gustavo A Madero, 07360, DF, México
| | - Mónica Mondragón Castelán
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN No 2508 Delegación Gustavo A Madero, 07360, DF, México
| | | | - Carlos J Ramírez Flores
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN No 2508 Delegación Gustavo A Madero, 07360, DF, México
| | | | - Carmen T Gómez de León
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN No 2508 Delegación Gustavo A Madero, 07360, DF, México
| | - Kitzia N Castro Elizalde
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN No 2508 Delegación Gustavo A Madero, 07360, DF, México
| | - Yovani Marrero Ponce
- Edificio de Especialidades Médicas, Hospital de los Valles, Colegio de Ciencias de la Salud, Universidad de San Francisco de Quito, Av. Interoceánica Km 12 1/2 Cumbayá, Quito, Ecuador
| | - Vicente J Arán
- Instituto de Química Médica, CSIC, c/ Juan de la Cierva 3, 28006, Madrid, España
| | - Miriam A Martins Alho
- Instituto de Química Médica, CSIC, c/ Juan de la Cierva 3, 28006, Madrid, España
- Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR-CONICET), Departamento de Química Orgánica, FCEN y LabMOr - INTECIN, FI, UBA, Paseo Colón 850, 5to. Piso, CP C1063ACV, Buenos Aires, Argentina
| | - Ricardo Mondragón Flores
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN No 2508 Delegación Gustavo A Madero, 07360, DF, México.
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Shimizu Y, Kushida Y, Kiriyama S, Nakano K, Numata O. Formation and ingression of division furrow can progress under the inhibitory condition of actin polymerization in ciliate Tetrahymena pyriformis. Zoolog Sci 2014; 30:1044-9. [PMID: 24328456 DOI: 10.2108/zsj.30.1044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In eukaryotic cells that multiply by binary fission, the interaction of actin filaments with myosin II in the contractile ring is widely recognized to generate force for membrane ingression into the cleavage furrow; however, the expression of myosin II is restricted in animals, yeast, fungi, and amoeba (collectively, unikonts). No corresponding motor protein capable of forming mini-filaments that could exert sufficient tension to cleave the cell body is found in bikonts, consisting of planta, algae, and most protozoa; however, cells in some bikont lineages multiply by binary fission, as do animal cells. Of these, the ciliate Tetrahymena is known to form an actin ring beneath the division furrow in cytokinesis. Here, we investigated the role of filamentous actin in the cytokinesis of Tetrahymena pyriformis by treating synchronized dividing cells with an actin-inhibiting drug, Latrunculin-A. Video microscopic observation of live cells undergoing cytokinesis was performed, and contrary to expectation, we found that initiation of furrow ingression and its progress are not suppressed under the inhibitory condition of actin polymerization in Tetrahymena cells. We suggest that an actin filament-independent mechanism of binary fission may have been acquired during the evolution in this organism.
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Affiliation(s)
- Yuhta Shimizu
- Biological Sciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
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Albendazole and its derivative JVG9 induce encystation on Giardia intestinalis trophozoites. Parasitol Res 2013; 112:3251-7. [DOI: 10.1007/s00436-013-3521-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 06/13/2013] [Indexed: 10/26/2022]
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Giardia flagellar motility is not directly required to maintain attachment to surfaces. PLoS Pathog 2011; 7:e1002167. [PMID: 21829364 PMCID: PMC3150270 DOI: 10.1371/journal.ppat.1002167] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 05/31/2011] [Indexed: 11/19/2022] Open
Abstract
Giardia trophozoites attach to the intestinal microvilli (or inert surfaces) using an undefined “suction-based” mechanism, and remain attached during cell division to avoid peristalsis. Flagellar motility is a key factor in Giardia's pathogenesis and colonization of the host small intestine. Specifically, the beating of the ventral flagella, one of four pairs of motile flagella, has been proposed to generate a hydrodynamic force that results in suction-based attachment via the adjacent ventral disc. We aimed to test this prevailing “hydrodynamic model” of attachment mediated by flagellar motility. We defined four distinct stages of attachment by assessing surface contacts of the trophozoite with the substrate during attachment using TIRF microscopy (TIRFM). The lateral crest of the ventral disc forms a continuous perimeter seal with the substrate, a cytological indication that trophozoites are fully attached. Using trophozoites with two types of molecularly engineered defects in flagellar beating, we determined that neither ventral flagellar beating, nor any flagellar beating, is necessary for the maintenance of attachment. Following a morpholino-based knockdown of PF16, a central pair protein, both the beating and morphology of flagella were defective, but trophozoites could still initiate proper surface contacts as seen using TIRFM and could maintain attachment in several biophysical assays. Trophozoites with impaired motility were able to attach as well as motile cells. We also generated a strain with defects in the ventral flagellar waveform by overexpressing a dominant negative form of alpha2-annexin::GFP (D122A, D275A). This dominant negative alpha2-annexin strain could initiate attachment and had only a slight decrease in the ability to withstand normal and shear forces. The time needed for attachment did increase in trophozoites with overall defective flagellar beating, however. Thus while not directly required for attachment, flagellar motility is important for positioning and orienting trophozoites prior to attachment. Drugs affecting flagellar motility may result in lower levels of attachment by indirectly limiting the number of parasites that can position the ventral disc properly against a surface and against peristaltic flow. Giardia is a widespread, single-celled, intestinal parasite that infects millions of people and animals each year. Colonization of the small intestine is a critical part of Giardia's life cycle in any host. This colonization is initiated when cells attach to the intestinal wall via a specialized suction cup-like structure, the ventral disc. In the host, Giardia moves by beating four pairs of flagella; movement of the ventral pair has been implicated in attachment. This study shows that the beating of the flagella is not important for attachment, but rather for positioning Giardia close to the intestinal wall prior to attachment, and thus disproves the commonly held model of giardial attachment. This work implies that drugs targeting Giardia motility could prevent or slow attachment, leading to lower rates of infection.
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An actin cytoskeleton with evolutionarily conserved functions in the absence of canonical actin-binding proteins. Proc Natl Acad Sci U S A 2011; 108:6151-6. [PMID: 21444821 DOI: 10.1073/pnas.1018593108] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Giardia intestinalis, a human intestinal parasite and member of what is perhaps the earliest-diverging eukaryotic lineage, contains the most divergent eukaryotic actin identified to date and is the first eukaryote known to lack all canonical actin-binding proteins (ABPs). We sought to investigate the properties and functions of the actin cytoskeleton in Giardia to determine whether Giardia actin (giActin) has reduced or conserved roles in core cellular processes. In vitro polymerization of giActin produced filaments, indicating that this divergent actin is a true filament-forming actin. We generated an anti-giActin antibody to localize giActin throughout the cell cycle. GiActin localized to the cortex, nuclei, internal axonemes, and formed C-shaped filaments along the anterior of the cell and a flagella-bundling helix. These structures were regulated with the cell cycle and in encysting cells giActin was recruited to the Golgi-like cyst wall processing vesicles. Knockdown of giActin demonstrated that giActin functions in cell morphogenesis, membrane trafficking, and cytokinesis. Additionally, Giardia contains a single G protein, giRac, which affects the Giardia actin cytoskeleton independently of known target ABPs. These results imply that there exist ancestral and perhaps conserved roles for actin in core cellular processes that are independent of canonical ABPs. Of medical significance, the divergent giActin cytoskeleton is essential and commonly used actin-disrupting drugs do not depolymerize giActin structures. Therefore, the giActin cytoskeleton is a promising drug target for treating giardiasis, as we predict drugs that interfere with the Giardia actin cytoskeleton will not affect the mammalian host.
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Synergic effect of metronidazole and pyrantel pamoate on Giardia lamblia. Parasitol Int 2011; 60:54-8. [DOI: 10.1016/j.parint.2010.10.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Revised: 09/15/2010] [Accepted: 10/05/2010] [Indexed: 11/17/2022]
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Castillo-Romero A, Leon-Avila G, Wang CC, Perez Rangel A, Camacho Nuez M, Garcia Tovar C, Ayala-Sumuano JT, Luna-Arias JP, Hernandez JM. Rab11 and actin cytoskeleton participate in Giardia lamblia encystation, guiding the specific vesicles to the cyst wall. PLoS Negl Trop Dis 2010; 4:e697. [PMID: 20532229 PMCID: PMC2879372 DOI: 10.1371/journal.pntd.0000697] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 04/06/2010] [Indexed: 12/30/2022] Open
Abstract
Background Giardia passes through two stages during its life cycle, the trophozoite and the cyst. Cyst formation involves the synthesis of cyst wall proteins (CWPs) and the transport of CWPs into encystation-specific vesicles (ESVs). Active vesicular trafficking is essential for encystation, but the molecular machinery driving vesicular trafficking remains unknown. The Rab proteins are involved in the targeting of vesicles to several intracellular compartments through their association with cytoskeletal motor proteins. Methodology and Principal Findings In this study, we found a relationship between Rab11 and the actin cytoskeleton in CWP1 transport. Confocal microscopy showed Rab11 was distributed throughout the entire trophozoite, while in cysts it was translocated to the periphery of the cell, where it colocalized with ESVs and microfilaments. Encystation was also accompanied by changes in rab11 mRNA expression. To evaluate the role of microfilaments in encystation, the cells were treated with latrunculin A. Scanning electron microscopy showed this treatment resulted in morphological damages to encysted parasites. The intensity of fluorescence-labeled Rab11 and CWP1 in ESVs and cyst walls was reduced, and rab11 and cwp1 mRNA levels were down-regulated. Furthermore, knocking down Rab11 with a hammerhead ribozyme resulted in an up to 80% down-regulation of rab11 mRNA. Although this knockdown did not appear lethal for trophozoites and did not affect cwp1 expression during the encystation, confocal images showed CWP1 was redistributed throughout the cytosol. Conclusions and Significance Our results indicate that Rab11 participates in the early and late encystation stages by regulating CWP1 localization and the actin-mediated transport of ESVs towards the periphery. In addition, alterations in the dynamics of actin affected rab11 and cwp1 expression. Our results provide new information about the molecules involved in Giardia encystation and suggest that Rab11 and actin may be useful as novel pharmacological targets. The encystation process is crucial for survival and transmission of Giardia lamblia to new hosts. During this process, vesicular trafficking and the cytoskeleton play important roles. In eukaryotic cells, intracellular transport is regulated by proteins, including Rab-GTPases and SNAREs, which regulate vesicle formation along with recognition of and binding to the target membrane. Cytoskeletal structures are also involved in these processes. In this study, we demonstrate the participation of Rab11 in the transport of encystation-specific vesicles (ESVs). Additionally, we demonstrate that disruption of actin microfilaments affects ESVs transport. The modification of actin dynamics was also correlated with a reduction in rab11 and cwp1 expression. Furthermore, down-regulation of rab11 mRNA by a specific hammerhead ribozyme caused nonspecific localization of CWP1. We thus provide new information about the molecular machinery that regulates Giardia lamblia encystation. Given our findings, Rab11 and actin may be useful targets to block Giardia encystation.
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Affiliation(s)
- Araceli Castillo-Romero
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México DF, México
| | - Gloria Leon-Avila
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, México DF, México
| | - Ching C. Wang
- Chemistry and Chemical Biology Graduate Program, Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Armando Perez Rangel
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México DF, México
| | - Minerva Camacho Nuez
- Departamento de Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, México DF, México
| | - Carlos Garcia Tovar
- Departamento de Ciencias Biológicas, FES-Cuautitlán Universidad Nacional Autónoma de México, México, México
| | | | - Juan Pedro Luna-Arias
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México DF, México
| | - Jose Manuel Hernandez
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México DF, México
- * E-mail:
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14
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Stefanić S, Spycher C, Morf L, Fabriàs G, Casas J, Schraner E, Wild P, Hehl AB, Sonda S. Glucosylceramide synthesis inhibition affects cell cycle progression, membrane trafficking, and stage differentiation in Giardia lamblia. J Lipid Res 2010; 51:2527-45. [PMID: 20335568 DOI: 10.1194/jlr.m003392] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Synthesis of glucosylceramide via glucosylceramide synthase (GCS) is a crucial event in higher eukaryotes, both for the production of complex glycosphingolipids and for regulating cellular levels of ceramide, a potent antiproliferative second messenger. In this study, we explored the dependence of the early branching eukaryote Giardia lamblia on GCS activity. Biochemical analyses revealed that the parasite has a GCS located in endoplasmic reticulum (ER) membranes that is active in proliferating and encysting trophozoites. Pharmacological inhibition of GCS induced aberrant cell division, characterized by arrest of cytokinesis, incomplete cleavage furrow formation, and consequent block of replication. Importantly, we showed that increased ceramide levels were responsible for the cytokinesis arrest. In addition, GCS inhibition resulted in prominent ultrastructural abnormalities, including accumulation of cytosolic vesicles, enlarged lysosomes, and clathrin disorganization. Moreover, anterograde trafficking of the encystations-specific protein CWP1 was severely compromised and resulted in inhibition of stage differentiation. Our results reveal novel aspects of lipid metabolism in G. lamblia and specifically highlight the vital role of GCS in regulating cell cycle progression, membrane trafficking events, and stage differentiation in this parasite. In addition, we identified ceramide as a potent bioactive molecule, underscoring the universal conservation of ceramide signaling in eukaryotes.
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Affiliation(s)
- Sasa Stefanić
- Institute of Parasitology, University of Zurich, Zurich, Switzerland
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15
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Participation of actin on Giardia lamblia growth and encystation. PLoS One 2009; 4:e7156. [PMID: 19774081 PMCID: PMC2743995 DOI: 10.1371/journal.pone.0007156] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 08/26/2009] [Indexed: 12/31/2022] Open
Abstract
Background Microfilaments play a determinant role in different cell processes such as: motility, cell division, phagocytosis and intracellular transport; however, these structures are poorly understood in the parasite Giardia lamblia. Methodology and Principal Findings By confocal microscopy using TRITC-phalloidin, we found structured actin distributed in the entire trophozoite, the label stand out at the ventral disc, median body, flagella and around the nuclei. During Giardia encystation, a sequence of morphological changes concurrent to modifications on the distribution of structured actin and in the expression of actin mRNA were observed. To elucidate whether actin participates actively on growth and encystation, cells were treated with Cytochalasin D, Latrunculin A and Jasplakinolide and analyzed by confocal and scanning electron microscopy. All drugs caused a growth reduction (27 to 45%) and changes on the distribution of actin. Besides, 60 to 80% of trophozoites treated with the drugs, exhibited damage at the caudal region, alterations in the flagella and wrinkles-like on the plasma membrane. The drugs also altered the cyst-yield and the morphology, scanning electron microscopy revealed diminished cytokinesis, cysts with damages in the wall and alterations in the size and on the intermembranal space. Furthermore, the drugs caused a significant reduction of the intensity of flourescence-labeled CWP1 on ESV and on cyst wall, this was coincident with a reduction of CWP1 gene expression (34%). Conclusions and Significance All our results, indicated an important role of actin in the morphology, growth and encystation and indirectly suggested an actin role in gene expression.
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16
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Hansen WR, Fletcher DA. Tonic shock induces detachment of Giardia lamblia. PLoS Negl Trop Dis 2008; 2:e169. [PMID: 18270543 PMCID: PMC2238710 DOI: 10.1371/journal.pntd.0000169] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2007] [Accepted: 12/13/2007] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The parasite Giardia lamblia must remain attached to the host small intestine in order to proliferate and subsequently cause disease. However, little is known about the factors that may cause detachment in vivo, such as changes in the aqueous environment. Osmolality within the proximal small intestine can vary by nearly an order of magnitude between host fed and fasted states, while pH can vary by several orders of magnitude. Giardia cells are known to regulate their volume when exposed to changes in osmolality, but the short-timescale effects of osmolality and pH on parasite attachment are not known. METHODOLOGY AND PRINCIPAL FINDINGS We used a closed flow chamber assay to test the effects of rapid changes in media osmolality, tonicity, and pH on Giardia attachment to both glass and C2(Bbe)-1 intestinal cell monolayer surfaces. We found that Giardia detach from both surfaces in a tonicity-dependent manner, where tonicity is the effective osmolality experienced by the cell. Detachment occurs with a characteristic time constant of 25 seconds (SD = 10 sec, n = 17) in both hypo- and hypertonic media but is otherwise insensitive to physiologically relevant changes in media composition and pH. Interestingly, cells that remain attached are able to adapt to moderate changes in tonicity. By exposing cells to a timed pattern of tonicity variations and adjustment periods, we found that it is possible to maximize the tonicity change experienced by the cells, overcoming the adaptive response and resulting in extensive detachment. CONCLUSIONS AND SIGNIFICANCE These results, conducted with human-infecting Giardia on human intestinal epithelial monolayers, highlight the ability of Giardia to adapt to the changing intestinal environment and suggest new possibilities for treatment of giardiasis by manipulation of tonicity in the intestinal lumen.
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Affiliation(s)
- Wendy R. Hansen
- Biophysics Graduate Group, University of California, Berkeley, California, United States of America
| | - Daniel A. Fletcher
- Biophysics Graduate Group, University of California, Berkeley, California, United States of America
- Department of Bioengineering, University of California, Berkeley, California, United States of America
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17
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A sphingolipid inhibitor induces a cytokinesis arrest and blocks stage differentiation in Giardia lamblia. Antimicrob Agents Chemother 2007; 52:563-9. [PMID: 18086854 DOI: 10.1128/aac.01105-07] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sphingolipid biosynthesis pathways have recently emerged as a promising target for therapeutic intervention against pathogens, including parasites. A key step in the synthesis of complex sphingolipids is the glucosylation of ceramide, mediated by glucosylceramide (GlcCer) synthase, whose activity can be inhibited by PPMP (1-phenyl-2-palmitoylamino-3-morpholino-1-propanol). In this study, we investigated whether PPMP inhibits the proliferation and differentiation of the pathogenic parasite Giardia lamblia, the major cause of parasite-induced diarrhea worldwide. PPMP was found to block in vitro parasite replication in a dose-dependent manner, with a 50% inhibitory concentration of 3.5 muM. The inhibition of parasite replication was irreversible at 10 muM PPMP, a concentration that did not affect mammalian cell metabolism. Importantly, PPMP inhibited the completion of cell division at a specific stage in late cytokinesis. Microscopic analysis of cells incubated with PPMP revealed the aberrant accumulation of cellular membranes belonging to the endoplasmic reticulum network in the caudal area of the parasites. Finally, PPMP induced a 90% reduction in G. lamblia differentiation into cysts, the parasite stage responsible for the transmission of the disease. These results show that PPMP is a powerful inhibitor of G. lamblia in vitro and that as-yet-uncharacterized sphingolipid biosynthetic pathways are potential targets for the development of anti-G. lamblia agents.
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18
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Hernandez Y, Castillo C, Roychowdhury S, Hehl A, Aley SB, Das S. Clathrin-dependent pathways and the cytoskeleton network are involved in ceramide endocytosis by a parasitic protozoan, Giardia lamblia. Int J Parasitol 2007; 37:21-32. [PMID: 17087963 PMCID: PMC1831817 DOI: 10.1016/j.ijpara.2006.09.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 09/07/2006] [Accepted: 09/11/2006] [Indexed: 11/16/2022]
Abstract
Although identified as an early-diverged protozoan, Giardia lamblia shares many similarities with higher eukaryotic cells, including an internal membrane system and cytoskeleton, as well as secretory pathways. However, unlike many other eukaryotes, Giardia does not synthesize lipids de novo, but rather depends on exogenous sources for both energy production and organelle or membrane biogenesis. It is not known how lipid molecules are taken up by this parasite and if endocytic pathways are involved in this process. In this investigation, we tested the hypothesis that highly regulated and selective lipid transport machinery is present in Giardia and necessary for the efficient internalization and intracellular targeting of ceramide molecules, the major sphingolipid precursor. Using metabolic and pathway inhibitors, we demonstrate that ceramide is internalized through endocytic pathways and is primarily targeted into perinuclear/endoplasmic reticulum membranes. Further investigations suggested that Giardia uses both clathrin-dependent pathways and the actin cytoskeleton for ceramide uptake, as well as microtubule filaments for intracellular localization and targeting. We speculate that this parasitic protozoan has evolved cytoskeletal and clathrin-dependent endocytic mechanisms for importing ceramide molecules from the cell exterior for the synthesis of membranes and vesicles during growth and differentiation.
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Affiliation(s)
- Yunuen Hernandez
- Infectious Diseases/Immunology, University of Texas at El Paso, TX 79968-0519, USA
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