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Amran A, Pigatto L, Farley J, Godini R, Pocock R, Gopal S. The matrisome landscape controlling in vivo germ cell fates. Nat Commun 2024; 15:4200. [PMID: 38760342 PMCID: PMC11101451 DOI: 10.1038/s41467-024-48283-4] [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: 08/17/2023] [Accepted: 04/26/2024] [Indexed: 05/19/2024] Open
Abstract
The developmental fate of cells is regulated by intrinsic factors and the extracellular environment. The extracellular matrix (matrisome) delivers chemical and mechanical cues that can modify cellular development. However, comprehensive understanding of how matrisome factors control cells in vivo is lacking. Here we show that specific matrisome factors act individually and collectively to control germ cell development. Surveying development of undifferentiated germline stem cells through to mature oocytes in the Caenorhabditis elegans germ line enabled holistic functional analysis of 443 conserved matrisome-coding genes. Using high-content imaging, 3D reconstruction, and cell behavior analysis, we identify 321 matrisome genes that impact germ cell development, the majority of which (>80%) are undescribed. Our analysis identifies key matrisome networks acting autonomously and non-autonomously to coordinate germ cell behavior. Further, our results demonstrate that germ cell development requires continual remodeling of the matrisome landscape. Together, this study provides a comprehensive platform for deciphering how extracellular signaling controls cellular development and anticipate this will establish new opportunities for manipulating cell fates.
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Affiliation(s)
- Aqilah Amran
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
- Lund Cancer Center, Lund University, Lund, Sweden
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute. Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Lara Pigatto
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
- Lund Cancer Center, Lund University, Lund, Sweden
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute. Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Johanna Farley
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
- Lund Cancer Center, Lund University, Lund, Sweden
| | - Rasoul Godini
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute. Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Roger Pocock
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute. Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia.
| | - Sandeep Gopal
- Department of Experimental Medical Science, Lund University, Lund, Sweden.
- Lund Stem Cell Center, Lund University, Lund, Sweden.
- Lund Cancer Center, Lund University, Lund, Sweden.
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute. Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia.
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2
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Enhancement of Neuroglial Extracellular Matrix Formation and Physiological Activity of Dopaminergic Neural Cocultures by Macromolecular Crowding. Cells 2022; 11:cells11142131. [PMID: 35883574 PMCID: PMC9317039 DOI: 10.3390/cells11142131] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/28/2022] [Accepted: 07/01/2022] [Indexed: 02/06/2023] Open
Abstract
The neuroglial extracellular matrix (ECM) provides critical support and physiological cues for the proper growth, differentiation, and function of neuronal cells in the brain. However, in most in vitro settings that study neural physiology, cells are grown as monolayers on stiff surfaces that maximize adhesion and proliferation, and, therefore, they lack the physiological cues that ECM in native neuronal tissues provides. Macromolecular crowding (MMC) is a biophysical phenomenon based on the principle of excluded volume that can be harnessed to induce native ECM deposition by cells in culture. Here, we show that MMC using two species of Ficoll with vitamin C supplementation significantly boosts deposition of relevant brain ECM by cultured human astrocytes. Dopaminergic neurons cocultured on this astrocyte–ECM bed prepared under MMC treatment showed longer and denser neuronal extensions, a higher number of pre ad post synaptic contacts, and increased physiological activity, as evidenced by higher frequency calcium oscillation, compared to standard coculture conditions. When the pharmacological activity of various compounds was tested on MMC-treated cocultures, their responses were enhanced, and for apomorphine, a D2-receptor agonist, it was inverted in comparison to control cell culture conditions, thus emulating responses observed in in vivo settings. These results indicate that macromolecular crowding can harness the ECM-building potential of human astrocytes in vitro forming an ultra-flat 3D microenvironment that makes neural cultures more physiological and pharmacological relevant.
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3
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Tsai SY, Huang CC, Chen PH, Tripathi A, Wang YR, Wang YL, Chen JC. Rapid Drug-Screening Platform Using Field-Effect Transistor-Based Biosensors: A Study of Extracellular Drug Effects on Transmembrane Potentials. Anal Chem 2021; 94:2679-2685. [PMID: 34919373 DOI: 10.1021/acs.analchem.1c03402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ion channel-modulating drugs play an important role in treating cardiovascular diseases. Facing the demands for continuous monitoring of drug effectiveness, the conventional techniques have become limited when investigating a long-term cellular physiology. To address the challenge, we propose a drug-screening platform using the stretch-out electrical double layer (EDL)-gated field-effect transistor-based biosensors (BioFETs). In this work, BioFETs were utilized to amplify electrophysiological signals from the mammalian cardiomyocytes (H9c2). The stretch-out configuration avoided a chemical corrosion on FETs and prolonged the lifetime of a BioFET system. A physical model is presented to elucidate the signal response to a drug effect on a cell. Fibronectin and gelatin were coated on sensors and served as the adhesive layers where H9c2 cells attached. BioFETs demonstrated an ability to qualitatively distinguish a depolarization and a polarization of the cytomembranes. The signal responses to the changes of transmembrane potentials were monitored in real-time, and they were highly correlated. The effects of nifedipine and calcium ions on cellular electrophysiology were examined and discussed. Due to the capability of a rapid detection, a prolonged lifetime, and an excellent sensitivity to an electrical change, a stretch-out EDL-gated BioFET can be a drug-screening platform for ion channel modulators.
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Affiliation(s)
- Shu-Yi Tsai
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Chih-Cheng Huang
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Po-Hsuan Chen
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Adarsh Tripathi
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Yu-Rong Wang
- Institute of Biomedical Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan, Republic of China
| | - Yu-Lin Wang
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China.,Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Jung-Chih Chen
- Institute of Biomedical Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan, Republic of China.,Department of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan, Republic of China.,Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan, Republic of China.,Catholic Mercy Hospital, Catholic Mercy Medical Foundation, Hsinchu 30342, Taiwan, Republic of China
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4
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Drug repositioning: antiprotozoal activity of terfenadine against Entamoeba histolytica trophozoites. Parasitol Res 2021; 121:303-309. [PMID: 34741218 DOI: 10.1007/s00436-021-07354-x] [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: 06/04/2021] [Accepted: 10/16/2021] [Indexed: 10/19/2022]
Abstract
The infection caused by Entamoeba histolytica is still a serious public health problem, especially in developing countries. The goal of this study was to evaluate the effect of terfenadine against Entamoeba histolytica. The trophozoites were exposed to 1, 2, 3, and 4 μM of terfenadine, for 24 and 48 h. Consequently, the viability of cells was determined by trypan blue exclusion test. The effect of terfenadine on adhesion of Entamoeba histolytica was evaluated in Caco-2 cells. In addition, the effect of terfenadine on the erythrophagocytic capacity of the parasite was investigated. The results show that terfenadine affects the growth and cell viability in a time- and dose-dependent manner. The higher inhibitory effects were observed with 4 µM at 48 h; 91.6% of growth inhibition and only 22.5% of trophozoites were viable. Additionally, we demonstrate that terfenadine is highly selective for the parasite and has low toxicity on Caco-2 cells. Furthermore, adhesion to Caco-2 cells and erythrophagocytic capacity were significantly inhibited. These findings demonstrate that terfenadine exerts significant effects on the virulence of Entamoeba histolytica. This is the first study demonstrating the amoebicidal activity of terfenadine and the results suggest it may be effective in the treatment of amoebiasis.
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Reyes-López M, Piña-Vázquez C, Pérez-Salazar E, de la Garza M. Endocytosis, signal transduction and proteolytic cleaving of human holotransferrin in Entamoeba histolytica. Int J Parasitol 2020; 50:959-967. [PMID: 32822678 DOI: 10.1016/j.ijpara.2020.05.013] [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: 11/26/2019] [Revised: 04/03/2020] [Accepted: 05/08/2020] [Indexed: 01/15/2023]
Abstract
Amoebiasis is a parasitic infection of the human large intestine caused by Entamoeba histolytica; this disease mainly affects people from developing countries. To survive, this primitive protozoan has a high demand for iron, and it uses host iron proteins upon invasion. Transferrin (Tf) is a plasma iron-binding protein that transports and delivers iron to all cells. Iron-loaded Tf (holoTf) in humans can support the proliferation of amoebae in vitro by binding to an amoebic TfR (EhTfR), and amoebae endocytose it inside clathrin-coated vesicles. In this study, it was found that EhTfR phosphorylation is required for human holoTf endocytosis by E. histolytica. Once this complex is endocytosed, human holoTf could be degraded with a nutritional purpose by cysteine proteases. HoloTf endocytosis initiates the activation of the mitogen-activated protein kinases (MAPKs) and focal adhesion kinase (FAK) pathways, which induce cell proliferation with phosphoinositide 3-kinase (PI-3 K) and Ca2+ involvement. In the first minutes after holoTf is endocytosed, several proteins are phosphorylated including transketolase, enolase, L-myo-inositol-1-phosphate synthase and phosphoglucomutase, which control carbohydrate metabolism, and heat shock protein-70. The study of these proteins and their signal transduction pathways could be useful for developing future therapies.
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Affiliation(s)
- Magda Reyes-López
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Ave. IPN 2508, Col. Zacatenco, CdMx 07360, Mexico
| | - Carolina Piña-Vázquez
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Ave. IPN 2508, Col. Zacatenco, CdMx 07360, Mexico
| | - Eduardo Pérez-Salazar
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Ave. IPN 2508, Col. Zacatenco, CdMx 07360, Mexico
| | - Mireya de la Garza
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Ave. IPN 2508, Col. Zacatenco, CdMx 07360, Mexico.
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6
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Tripathi A, Jain M, Chandra M, Parveen S, Yadav R, Collins BM, Maiti S, Datta S. EhC2B, a C2 domain-containing protein, promotes erythrophagocytosis in Entamoeba histolytica via actin nucleation. PLoS Pathog 2020; 16:e1008489. [PMID: 32365140 PMCID: PMC7197785 DOI: 10.1371/journal.ppat.1008489] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/23/2020] [Indexed: 12/17/2022] Open
Abstract
Remodelling of the actin cytoskeleton in response to external stimuli is obligatory for many cellular processes in the amoebic cell. A rapid and local rearrangement of the actin cytoskeleton is required for the development of the cellular protrusions during phagocytosis, trogocytosis, migration, and invasion. Here, we demonstrated that EhC2B, a C2 domain-containing protein, is an actin modulator. EhC2B was first identified as an effector of EhRab21 from E. histolytica. In vitro interaction studies including GST pull-down, fluorescence-based assay and ITC also corroborated with our observation. In the amoebic trophozoites, EhC2B accumulates at the pseudopods and the tips of phagocytic cups. FRAP based studies confirmed the recruitment and dynamics of EhC2B at the phagocytic cup. Moreover, we have shown the role of EhC2B in erythrophagocytosis. It is well known that calcium-dependent signal transduction is essential for the cytoskeletal dynamics during phagocytosis in the amoebic parasite. Using liposome pelleting assay, we demonstrated that EhC2B preferentially binds to the phosphatidylserine in the presence of calcium. The EhC2B mutants defective in calcium or lipid-binding failed to localise beneath the plasma membrane. The cells overexpressing these mutants have also shown a significant reduction in erythrophagocytosis. The role of EhC2B in erythrophagocytosis and pseudopod formation was also validated by siRNA-based gene knockdown approach. Finally, with the help of in vitro nucleation assay using fluorescence spectroscopy and total internal reflection fluorescence microscopy, we have established that EhC2B is an actin nucleator. Collectively, based on the results from the study, we propose that EhC2B acts like a molecular bridge which promotes membrane deformation via its actin nucleation activity during the progression of the phagocytic cup in a calcium-dependent manner.
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Affiliation(s)
- Aashutosh Tripathi
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Megha Jain
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Mintu Chandra
- Institute for Molecular Biosciences, University of Queensland, St Lucia, Australia
| | - Sameena Parveen
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Rupali Yadav
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Brett M. Collins
- Institute for Molecular Biosciences, University of Queensland, St Lucia, Australia
| | - Sankar Maiti
- Department of Biological Sciences, Indian Institute of Science Education and Research, Kolkata, India
| | - Sunando Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
- * E-mail:
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7
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Calcium in Cell-Extracellular Matrix Interactions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:1079-1102. [PMID: 31646546 DOI: 10.1007/978-3-030-12457-1_43] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In multicellular organisms, the cells are surrounded by persistent, dynamic extracellular matrix (ECM), the largest calcium reservoir in animals. ECM regulates several aspects of cell behavior including cell migration and adhesion, survival, gene expression and differentiation, thus playing a significant role in health and disease. Calcium is reported to be important in the assembly of ECM, where it binds to many ECM proteins. While serving as a calcium reservoir, ECM macromolecules can directly interact with cell surface receptors resulting in calcium transport across the membrane. This chapter mainly focusses on the role of cell-ECM interactions in cellular calcium regulation and how calcium itself mediates these interactions.
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Valle-Solis M, Bolaños J, Orozco E, Huerta M, García-Rivera G, Salas-Casas A, Chávez-Munguía B, Rodríguez MA. A Calcium/Cation Exchanger Participates in the Programmed Cell Death and in vitro Virulence of Entamoeba histolytica. Front Cell Infect Microbiol 2018; 8:342. [PMID: 30327757 PMCID: PMC6174217 DOI: 10.3389/fcimb.2018.00342] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 09/10/2018] [Indexed: 01/17/2023] Open
Abstract
Entamoeba histolytica is the etiologic agent of human amoebiasis, disease that causes 40,000 to 100,000 deaths annually worldwide. The cytopathic activity as well as the growth and differentiation of this microorganism is dependent on both, extracellular and free cytoplasmic calcium. However, few is known about the proteins that regulate the calcium flux in this parasite. In many cells, the calcium extrusion from the cytosol is performed by plasma membrane Ca2+-ATPases and calcium/cation exchangers. The aim of this work was to identify a calcium/cation exchanger of E. histolytica and to analyze its possible role in some cellular processes triggered by calcium flux, such as the programmed cell death and in vitro virulence. By searching putative calcium/cation exchangers in the genome database of E. histolyica we identified a protein belonging to the CCX family (EhCCX). We generated a specific antibody against EhCCX, which showed that this protein was expressed in higher levels in E. histolytica than its orthologous in the non-pathogenic amoeba E. dispar. In addition, the expression of EhCCX was increased in trophozoites incubated with hydrogen peroxide. This E. histolytica exchanger was localized in the plasma membrane and in the membrane of some cytoplasmic vesicles. However, after 10 min of erythrophagocytosis, EhCCX was found predominantly in the plasma membrane of the trophozoites. On the other hand, the parasites that overexpress this exchanger contained higher cytosolic calcium levels than control, but the extrusion of calcium after the addition of hydrogen peroxide was more efficient in EhCCX-overexpressing trophozoites; consequently, the programmed cell death was retarded in these parasites. Interestingly, the overexpression of EhCCX increased the in vitro virulence of trophozoites. These results suggest that EhCCX plays important roles in the programmed cell death and in the in vitro virulence of E. histolytica.
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Affiliation(s)
- Martha Valle-Solis
- Departamento de Infectómica y Patogénesis Molecular, CINVESTAV-IPN, Mexico City, Mexico
| | - Jeni Bolaños
- Departamento de Infectómica y Patogénesis Molecular, CINVESTAV-IPN, Mexico City, Mexico
| | - Esther Orozco
- Departamento de Infectómica y Patogénesis Molecular, CINVESTAV-IPN, Mexico City, Mexico
| | - Miriam Huerta
- Departamento de Infectómica y Patogénesis Molecular, CINVESTAV-IPN, Mexico City, Mexico
| | | | - Andrés Salas-Casas
- Área Académica de Gerontología, Instituto de Ciencias de la Salud, Universidad Autónoma del Estado de Hidalgo, Pachuca, Mexico
| | | | - Mario A Rodríguez
- Departamento de Infectómica y Patogénesis Molecular, CINVESTAV-IPN, Mexico City, Mexico
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9
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Rodríguez MA, Martínez-Higuera A, Valle-Solis MI, Hernandes-Alejandro M, Chávez-Munguía B, Figueroa-Gutiérrez AH, Salas-Casas A. A putative calcium-ATPase of the secretory pathway family may regulate calcium/manganese levels in the Golgi apparatus of Entamoeba histolytica. Parasitol Res 2018; 117:3381-3389. [PMID: 30084034 DOI: 10.1007/s00436-018-6030-4] [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: 02/28/2018] [Accepted: 07/25/2018] [Indexed: 01/01/2023]
Abstract
Calcium regulates many cellular processes in protozoa, including growth, differentiation, programmed cell death, exocytosis, endocytosis, phagocytosis, fusion of the endosomes of distinct stages with phagosomes, fusion of phagosomes with lysosomes, and recycling the membrane. In Entamoeba histolytica, the protozoa responsible for human amoebiasis, calcium ions are essential for signaling pathways that lead to growth and development. In addition, calcium is crucial in the modulation of gene expression in this microorganism. However, there is scant information about the proteins responsible for regulating calcium levels in this parasite. In this work, we characterized a protein of E. histolytica that shows a close phylogenetic relationship with Ca2+ pumps that belong to the family of secretory pathway calcium ATPases (SPCA), which for several organisms are located in the Golgi apparatus. The amoeba protein analyzed herein has several amino acid residues that are characteristic of SPCA members. By an immunofluorescent technique using specific antibodies and immunoelectron microscopy, the protein was detected on the membrane of some cytoplasmic vacuoles. Moreover, this putative calcium-ATPase was located in vacuoles stained with NBD C6-ceramide, a Golgi marker. Overall, the current findings support the hypothesis that the presently analyzed protein corresponds to the SPCA of E. histolytica.
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Affiliation(s)
- Mario A Rodríguez
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, Mexico
| | | | - Martha I Valle-Solis
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, Mexico
| | - Mario Hernandes-Alejandro
- Departamento de Bioingeniería, Unidad Profesional Interdisciplinaria de Biotecnología del Instituto Politécnico Nacional (UPIBI-IPN), Mexico City, Mexico
| | - Bibiana Chávez-Munguía
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, Mexico
| | - Ana H Figueroa-Gutiérrez
- Instituto de Ciencias de la Salud, Área Académica de Gerontología, Universidad Autónoma del Estado de Hidalgo, Ex Hacienda la Concepción, s/n; Carretera Actopan-Tilcuautla, San Agustín Tlaxiaca, Hidalgo, Mexico
| | - Andrés Salas-Casas
- Instituto de Ciencias de la Salud, Área Académica de Gerontología, Universidad Autónoma del Estado de Hidalgo, Ex Hacienda la Concepción, s/n; Carretera Actopan-Tilcuautla, San Agustín Tlaxiaca, Hidalgo, Mexico.
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Yadav R, Verma K, Chandra M, Mukherjee M, Datta S. Biophysical studies on calcium and carbohydrate binding to carbohydrate recognition domain of Gal/GalNAc lectin fromEntamoeba histolytica: insights into host cell adhesion. J Biochem 2016; 160:177-86. [DOI: 10.1093/jb/mvw024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 03/08/2016] [Indexed: 11/14/2022] Open
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Entamoeba invadens: Identification of a SERCA protein and effect of SERCA inhibitors on encystation. Microb Pathog 2015; 89:18-26. [DOI: 10.1016/j.micpath.2015.08.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 08/21/2015] [Accepted: 08/24/2015] [Indexed: 11/22/2022]
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12
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Lee YA, Kim KA, Min A, Shin MH. Amoebic PI3K and PKC is required for Jurkat T cell death induced by Entamoeba histolytica. THE KOREAN JOURNAL OF PARASITOLOGY 2014; 52:355-65. [PMID: 25246714 PMCID: PMC4170031 DOI: 10.3347/kjp.2014.52.4.355] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Revised: 05/29/2014] [Accepted: 06/04/2014] [Indexed: 01/01/2023]
Abstract
The enteric protozoan parasite Entamoeba histolytica is the causative agent of human amebiasis. During infection, adherence of E. histolytica through Gal/GalNAc lectin on the surface of the amoeba can induce caspase-3-dependent or -independent host cell death. Phosphorylinositol 3-kinase (PI3K) and protein kinase C (PKC) in E. histolytica play an important function in the adhesion, killing, or phagocytosis of target cells. In this study, we examined the role of amoebic PI3K and PKC in amoeba-induced apoptotic cell death in Jurkat T cells. When Jurkat T cells were incubated with E. histolytica trophozoites, phosphatidylserine (PS) externalization and DNA fragmentation in Jurkat cells were markedly increased compared to those of cells incubated with medium alone. However, when amoebae were pretreated with a PI3K inhibitor, wortmannin before being incubated with E. histolytica, E. histolytica-induced PS externalization and DNA fragmentation in Jurkat cells were significantly reduced compared to results for amoebae pretreated with DMSO. In addition, pretreatment of amoebae with a PKC inhibitor, staurosporine strongly inhibited Jurkat T cell death. However, E. histolytica-induced cleavage of caspase-3, -6, and -7 were not inhibited by pretreatment of amoebae with wortmannin or staurosporin. In addition, we found that amoebic PI3K and PKC have an important role on amoeba adhesion to host compartment. These results suggest that amebic PI3K and PKC activation may play an important role in caspase-independent cell death in Entamoeba-induced apoptosis.
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Affiliation(s)
- Young Ah Lee
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Kyeong Ah Kim
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Arim Min
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Myeong Heon Shin
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 120-752, Korea
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Martinez-Higuera A, Salas-Casas A, Calixto-Gálvez M, Chávez-Munguía B, Pérez-Ishiwara DG, Ximénez C, Rodríguez MA. Identification of calcium-transporting ATPases of Entamoeba histolytica and cellular localization of the putative SERCA. Exp Parasitol 2013; 135:79-86. [DOI: 10.1016/j.exppara.2013.06.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 05/15/2013] [Accepted: 06/12/2013] [Indexed: 11/28/2022]
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14
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Localization of phosphatidylinositol 4,5-bisphosphate to lipid rafts and uroids in the human protozoan parasite Entamoeba histolytica. Infect Immun 2013; 81:2145-55. [PMID: 23545298 DOI: 10.1128/iai.00040-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Entamoeba histolytica is an intestinal protozoan parasite and is the causative agent of amoebiasis. During invasive infection, highly motile amoebae destroy the colonic epithelium, enter the blood circulation, and disseminate to other organs such as liver, causing liver abscess. Motility is a key factor in E. histolytica pathogenesis, and this process relies on a dynamic actomyosin cytoskeleton. In other systems, phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is known to regulate a wide variety of cellular functions, including signal transduction, actin remodeling, and cell motility. Little is known about the role of PI(4,5)P2 in E. histolytica pathogenicity. In this study, we demonstrate that PI(4,5)P2 is localized to cholesterol-rich microdomains, lipid rafts, and the actin-rich fractions of the E. histolytica membrane. Microscopy revealed that the trailing edge of polarized trophozoites, uroids, are highly enriched in lipid rafts and their constituent lipid, PI(4,5)P2. Polarization and enrichment of uroids and rafts with PI(4,5)P2 were enhanced upon treatment of E. histolytica cells with cholesterol. Exposure to cholesterol also increased intracellular calcium, which is a downstream effector of PI(4,5)P2, with a concomitant increase in motility. Together, our data suggest that in E. histolytica, PI(4,5)P2 may signal from lipid rafts and cholesterol may play a role in triggering PI(4,5)P2-mediated signaling to enhance the motility of this pathogen.
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Abstract
The parasite Entamoeba histolytica causes amebic colitis and systemic amebiasis. Among the known amebic factors contributing to pathogenesis are signaling pathways involving heterotrimeric and Ras superfamily G proteins. Here, we review the current knowledge of the roles of heterotrimeric G protein subunits, Ras, Rho and Rab GTPase families in E. histolytica pathogenesis, as well as of their downstream signaling effectors and nucleotide cycle regulators. Heterotrimeric G protein signaling likely modulates amebic motility and attachment to and killing of host cells, in part through activation of an RGS-RhoGEF (regulator of G protein signaling-Rho guanine nucleotide exchange factor) effector. Rho family GTPases, as well as RhoGEFs and Rho effectors (formins and p21-activated kinases) regulate the dynamic actin cytoskeleton of E. histolytica and associated pathogenesis-related cellular processes, such as migration, invasion, phagocytosis and evasion of the host immune response by surface receptor capping. A remarkably large family of 91 Rab GTPases has multiple roles in a complex amebic vesicular trafficking system required for phagocytosis and pinocytosis and secretion of known virulence factors, such as amebapores and cysteine proteases. Although much remains to be discovered, recent studies of G protein signaling in E. histolytica have enhanced our understanding of parasitic pathogenesis and have also highlighted possible targets for pharmacological manipulation.
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Exposure to host ligands correlates with colocalization of Gal/GalNAc lectin subunits in lipid rafts and phosphatidylinositol (4,5)-bisphosphate signaling in Entamoeba histolytica. EUKARYOTIC CELL 2012; 11:743-51. [PMID: 22505337 DOI: 10.1128/ec.00054-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Entamoeba histolytica is an intestinal parasite that causes dysentery and liver abscess. Parasite cell surface receptors, such as the Gal/GalNAc lectin, facilitate attachment to host cells and extracellular matrix. The Gal/GalNAc lectin binds to galactose or N-acetylgalactosamine residues on host components and is composed of heavy (Hgl), intermediate (Igl), and light (Lgl) subunits. Although Igl is constitutively localized to lipid rafts (cholesterol-rich membrane domains), Hgl and Lgl transiently associate with this compartment in a cholesterol-dependent fashion. In this study, trophozoites were exposed to biologically relevant ligands to determine if ligand binding influences the submembrane distribution of the subunits. Exposure to human red blood cells (hRBCs) or collagen, which are bona fide Gal/GalNAc lectin ligands, was correlated with enrichment of Hgl and Lgl in rafts. This enrichment was abrogated in the presence of galactose, suggesting that direct lectin-ligand interactions are necessary to influence subunit location. Using a cell line that is able to attach to, but not phagocytose, hRBCs, it was shown that physical attachment to ligands was not sufficient to induce the enrichment of lectin subunits in rafts. Additionally, the mutant had lower levels of phosphatidylinositol (4,5)-bisphosphate (PIP(2)); PIP(2) loading restored the ability of this mutant to respond to ligands with enrichment of subunits in rafts. Finally, intracellular calcium levels increased upon attachment to collagen; this increase was essential for the enrichment of lectin subunits in rafts. Together, these data provide evidence that ligand-induced enrichment of lectin subunits in rafts may be the first step in a signaling pathway that involves both PIP(2) and calcium signaling.
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Phospholipid-binding protein EhC2A mediates calcium-dependent translocation of transcription factor URE3-BP to the plasma membrane of Entamoeba histolytica. EUKARYOTIC CELL 2009; 9:695-704. [PMID: 20023071 DOI: 10.1128/ec.00346-09] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The Entamoeba histolytica upstream regulatory element 3-binding protein (URE3-BP) is a transcription factor that binds DNA in a Ca(2+)-inhibitable manner. The protein is located in both the nucleus and the cytoplasm but has also been found to be enriched in the plasma membrane of amebic trophozoites. We investigated the reason for the unusual localization of URE3-BP at the amebic plasma membrane. Here we identify and characterize a 22-kDa Ca(2+)-dependent binding partner of URE3-BP, EhC2A, a novel member of the C2-domain superfamily. Immunoprecipitations of URE3-BP and EhC2A showed that the proteins interact and that such interaction was enhanced in the presence of Ca(2+). Recombinant and native EhC2A bound phospholipid liposomes in a Ca(2+)-dependent manner, with half-maximal binding occurring at 3.4 muM free Ca(2+). A direct interaction between EhC2A and URE3-BP was demonstrated by the ability of recombinant EhC2A to recruit recombinant URE3-BP to phospholipid liposomes in a Ca(2+)-dependent manner. URE3-BP and EhC2A were observed to translocate to the amebic plasma membrane upon an increase in the intracellular Ca(2+) concentration of trophozoites, as revealed by subcellular fractionation and immunofluorescent staining. Short hairpin RNA-mediated knockdown of EhC2A protein expression significantly modulated the mRNA levels of URE3-BP-regulated transcripts. Based on these results, we propose a model for EhC2A-mediated regulation of the transcriptional activities of URE3-BP via Ca(2+)-dependent anchoring of the transcription factor to the amebic plasma membrane.
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Jain R, Santi-Rocca J, Padhan N, Bhattacharya S, Guillen N, Bhattacharya A. Calcium-binding protein 1 of Entamoeba histolytica transiently associates with phagocytic cups in a calcium-independent manner. Cell Microbiol 2008; 10:1373-89. [PMID: 18341598 DOI: 10.1111/j.1462-5822.2008.01134.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Ruchi Jain
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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Mustafi SM, Mukherjee S, Chary KVR, Cavallaro G. Structural basis for the observed differential magnetic anisotropic tensorial values in calcium binding proteins. Proteins 2006; 65:656-69. [PMID: 16981203 DOI: 10.1002/prot.21121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Lanthanide ions (Ln(3+)), which have ionic radii similar to those of Ca(2+), can displace the latter in a calcium binding protein, without affecting its tertiary structure. The paramagnetic Ln(3+) possesses large anisotropic magnetic susceptibilities and produce pseudocontact shifts (PCSs), which have r(-3) dependence. The PCS can be seen for spins as far as 45 A from the paramagnetic ion. They aid in structure refinement of proteins by providing long-range distance constraints. Besides, they can be used to determine the interdomain orientation in multidomain proteins. This is particularly important in the context of a calcium binding protein from Entamoeba histolytica (EhCaBP), which consists of two globular domains connected by a flexible linker region containing 8 residues. As a first step to obtain the interdomain orientation in EhCaBP, a suite of 2D and 3D heteronuclear experiments were recorded on EhCaBP by displacing calcium with Ce(3+), Ho(3+), Er(3+), Tm(3+), Dy(3+), and Yb(3+) ions in separate experiments, and the PCS of (1)H(N) and (15)N spins were measured. Such data have been used in the refinement of the individual domain structures of the protein in parallel with the calculation of the respective magnetic anisotropy tensorial values, which differ substantially (2.1-2.8 times) from what is found in other Ca(2+) binding loops. This study provides a structural basis for such variations in the magnetic anisotropy tensorial values.
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Affiliation(s)
- Sourajit M Mustafi
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
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Rocha-Azevedo B, Jamerson M, Cabral GA, Silva-Filho FC, Marciano-Cabral F. The interaction between the amoebaBalamuthia mandrillarisand extracellular matrix glycoproteinsin vitro. Parasitology 2006; 134:51-8. [PMID: 17032481 DOI: 10.1017/s0031182006001272] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Revised: 07/05/2006] [Accepted: 07/05/2006] [Indexed: 11/06/2022]
Abstract
Balamuthia mandrillaris, a soil amoeba, is the causative agent ofBalamuthiagranulomatous amoebic encephalitis, a life-threatening brain infection. This amoeba is acquired from contaminated soil and may enter the host through cutaneous lesions or through nasal passages, migrating to the lungs or brain. During invasion,B. mandrillarishas access to components of the extracellular matrix (ECM) of the host. Therefore, we investigated the interaction ofB. mandrillariswith 3 ECM glycoproteins (collagen-I, fibronectin and laminin-1) that are encountered in host connective tissues and at the basal lamina. Using optical microscopy, amoeba association on ECM-coated surfaces was examined. Binding of amoebae on laminin was greater than that on collagen or fibronectin. Laminin-adheredB. mandrillarisexhibited elongated and spread forms, distinctive from those observed for amoebae on a plastic surface. Collagen and fibronectin-adheredB. mandrillarispresented elongated shapes with cellular expansions. Binding to collagen, fibronectin, or laminin was inhibited when amoebae were pre-treated with sialic acid. Treatment with galactose resulted in diminished binding of amoebae on laminin, while mannose increased binding in all coating conditions tested. Dependence of divalent cations on amoeba binding was demonstrated for laminin-amoeba interaction. Collectively, the results indicate thatB. mandrillarisrecognizes specific glycoproteins of the mammalian extracellular matrix.
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Affiliation(s)
- B Rocha-Azevedo
- Programa de Bioengenharia e Biotecnologia Animal, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Arias-Romero LE, de Jesús Almáraz-Barrera M, Díaz-Valencia JD, Rojo-Domínguez A, Hernandez-Rivas R, Vargas M. EhPAK2, a novel p21-activated kinase, is required for collagen invasion and capping in Entamoeba histolytica. Mol Biochem Parasitol 2006; 149:17-26. [PMID: 16716419 DOI: 10.1016/j.molbiopara.2006.04.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Revised: 04/03/2006] [Accepted: 04/04/2006] [Indexed: 12/22/2022]
Abstract
p21-activated kinases (PAKs) are a highly conserved family of enzymes that are activated by Rho GTPases. All PAKs contain an N-terminal Cdc42/Rac interacting binding (CRIB) domain, which confers binding to these GTPases, and a C-terminal kinase domain. In addition, some PAKs such as Cla4p, Skm1p and Pak2p contain an N-terminal pleckstrin homology (PH) domain and form a distinct group of PAK proteins involved in cell morphology, cell-cycle and gene transcription. Here, we describe a novel p21-activated kinase, denominated EhPAK2, on the parasitic protozoan Entamoeba histolytica. This is the first reported Entamoeba PAK member that contains a N-terminal PH domain and a highly conserved CRIB domain. EhPAK2 CRIB domain shares 29% of amino acid identity and 53% of amino acid homology with these of DdPAKC from Dictyostelium discoideum and Cla4p from Saccharomyces cerevisiae and binds in vitro and in vivo to EhRacA GTPase. This domain also possesses the conserved residues His123, Phe134 and Trp141, which are important for the interaction with the effector loop and strand beta2 of the GTPase; and the residues Met121 and Phe145, which are specific for the interaction of EhPAK2 with EhRacA. Functional studies of EhPAK2 showed that its C-terminal kinase domain had activity toward myelin basic protein. Cellular studies showed that Entamoeba trophozoites transfected with the vector pExEhNeo/kinase-myc, had a 90% decrease in the ability to invade a collagen matrix as well as severe defects in capping, suggesting the involvement of EhPAK2 in these cellular processes.
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Affiliation(s)
- Luis Enrique Arias-Romero
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios, Avanzados del IPN, Mexico, DF, Mexico
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Meza I, Talamás-Rohana P, Vargas MA. The Cytoskeleton of Entamoeba histolytica: Structure, Function, and Regulation by Signaling Pathways. Arch Med Res 2006; 37:234-43. [PMID: 16380324 DOI: 10.1016/j.arcmed.2005.09.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2005] [Accepted: 09/26/2005] [Indexed: 01/16/2023]
Abstract
Pathogenesis in the parasite Entamoeba histolytica has been related to motility of the trophozoites. Motility is an important feature in amebas as they perform multiple motile functions during invasion of host tissues. As motility depends on the organization and regulation of the cytoskeleton elements, in particular of the actin cytoskeleton, the study of the molecular components of the machinery responsible for movement has been a key aspect to study in this parasite. Although many of the components have high homology in amino acid sequence and function to those characterized in higher eukaryotic cells, there are important differences to suggest that parasitic organisms may have developed adaptative differences that could be useful as targets to stop invasion. The purpose of this review is to evaluate current knowledge about the cytoskeleton of E. histolytica and the ways in which the parasite controls motility.
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Affiliation(s)
- Isaura Meza
- Departamentos de Biomedicina Molecular, Centro de Investigación y de Estudios, Avanzados del IPN, México D.F., México.
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Davis PH, Zhang Z, Chen M, Zhang X, Chakraborty S, Stanley SL. Identification of a family of BspA like surface proteins of Entamoeba histolytica with novel leucine rich repeats. Mol Biochem Parasitol 2005; 145:111-6. [PMID: 16199101 PMCID: PMC1382194 DOI: 10.1016/j.molbiopara.2005.08.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2005] [Revised: 07/26/2005] [Accepted: 08/29/2005] [Indexed: 11/25/2022]
Affiliation(s)
- Paul H Davis
- Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA
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Evolution of Ca2+-Signaling Mechanisms. Role of Calcium Ions in Signal Transduction in Lower Eukaryotes. J EVOL BIOCHEM PHYS+ 2005. [DOI: 10.1007/s10893-005-0073-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Sahoo N, Labruyère E, Bhattacharya S, Sen P, Guillén N, Bhattacharya A. Calcium binding protein 1 of the protozoan parasite Entamoeba histolytica interacts with actin and is involved in cytoskeleton dynamics. J Cell Sci 2005; 117:3625-34. [PMID: 15252130 DOI: 10.1242/jcs.01198] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Blocking expression of EhCaBP1, a calmodulin-like, four EF-hand protein from the protozoan parasite Entamoeba histolytica, resulted in inhibition of cellular proliferation. In this paper we report that EhCaBP1 is involved in dynamic changes of the actin cytoskeleton. Both endocytosis and phagocytosis were severely impaired in cells where EhCaBP1 expression was blocked by inducible expression of the antisense RNA. In wild-type cells both actin and EhCaBP1 were found to co-localize in phagocytic cups and in pseudopods. However, in antisense-blocked cells the phagocytic cup formation is affected. Analysis of the staining patterns in the presence and absence of actin dynamics inhibitors, jasplakinolide and cytochalasin D suggested that EhCaBP1 and polymerized F-actin co-localize on membrane protrusions. Direct interaction between soluble EhCaBP1 and F-actin was further demonstrated by a co-sedimentation assay. A variant of EhCaBP1 did not bind F-actin showing the specificity of the interaction between EhCaBP1 and actin. There is no significant change in the kinetics of in vitro polymerization of actin in presence of EhCaBP1, indicating that EhCaBP1 does not affect filament treadmilling. In addition, using atomic force microscopy; it was found that filaments of F-actin, polymerized in presence of EhCaBP1, were thinner. These results indicate that EhCaBP1 may be involved in dynamic membrane restructuring at the time of cell pseudopod formation, phagocytosis and endocytosis in a process mediated by direct binding of EhCaBP1 to actin, affecting the bundling of actin filaments.
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Affiliation(s)
- Nivedita Sahoo
- School of Life Sciences, Jawaharlal Nehru University, Aruna Asaf Ali Marg, New Delhi, 110067 India
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Lavazec C, Bonnet S, Thiery I, Boisson B, Bourgouin C. cpbAg1 encodes an active carboxypeptidase B expressed in the midgut of Anopheles gambiae. INSECT MOLECULAR BIOLOGY 2005; 14:163-174. [PMID: 15796749 DOI: 10.1111/j.1365-2583.2004.00541.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We previously used differential display to identify several Anopheles gambiae genes, whose expression in the mosquito midgut was regulated upon ingestion of Plasmodium falciparum. Here, we report the characterization of one of these genes, cpbAg1, which codes for the first zinc-carboxypeptidase B identified in An. gambiae and in any insect. Expression of cpbAg1 in baculovirus gave rise to an active enzyme, and determination of the N-terminal amino acids confirmed that CPBAg1 contains a signal peptide and a pro-peptide, typical features of digestive zinc carboxypeptidases. cpbAg1 mRNA was mainly produced in the mosquito midgut, where it accumulated in unfed females and was rapidly down-regulated upon blood feeding. Annotation of the An. gambiae genome predicts twenty-three sequences coding for zinc-carboxypeptidases of which only two (cpbAg1 and cpbAg2) are expressed at a significant level in the mosquito midgut.
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Affiliation(s)
- C Lavazec
- Unité de Biologie et Génétique du Paludisme, Institut Pasteur, Paris, France
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Batista EDJO, de Souza W. Involvement of protein kinases on the process of erythrophagocytis by Entamoeba histolytica. Cell Biol Int 2005; 28:243-8. [PMID: 15109979 DOI: 10.1016/j.cellbi.2004.01.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2003] [Revised: 11/25/2003] [Accepted: 01/20/2004] [Indexed: 10/26/2022]
Abstract
Erythrophagocytic capacity of trophozoites of Entamoeba histolytica is considered a factor in the virulence of this pathogenic protozoan. We present evidence showing that such activity resembles the ingestion of microorganisms by highly differentiated phagocytic cells, such as macrophages. Previous treatment of the trophozoites with genistein or tyrphostin, inhibitors of tyrosine protein kinases, with staurosporine, a protein kinase C inhibitor, and wortmannin, a fungal metabolite that inhibits phosphoinositide 3-OH kinase, significantly inhibited their erythrophagocytic capacity.
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Affiliation(s)
- Evander de J O Batista
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS-Bloco G, Ilha do Fundão, Rio de Janeiro RJ, 21941-900, Brazil
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Gilchrist CA, Leo M, Line CG, Mann BJ, Petri WA. Calcium modulates promoter occupancy by the Entamoeba histolytica Ca2+-binding transcription factor URE3-BP. J Biol Chem 2003; 278:4646-53. [PMID: 12466263 DOI: 10.1074/jbc.m211271200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Entamoeba histolytica upstream regulatory element 3-binding protein (URE3-BP) binds to the URE3 sequence of the Gal/GalNAc-inhibitable lectin hgl5 and ferredoxin 1 (fdx) gene promoters. This binding can be inhibited in vitro by addition of calcium. Two EF-hand motifs, which are associated with the ability to bind calcium, are present in the amino acid sequence of URE3-BP. Mutation of the second EF-hand motif in URE3-BP resulted in the loss of calcium inhibition of DNA binding as monitored by electrophoretic mobility shift assay. Chromatin immunoprecipitation assays revealed that URE3-BP was physically bound to the hgl5 and fdx promoters in vivo. Parasite intracellular calcium concentrations were altered by changes in extracellular calcium. Promoter occupancy was lost when intracellular calcium levels were increased by coordinate increases in extracellular calcium. Increased intracellular calcium also resulted in decreased levels of URE3-BP mRNA. Together these results demonstrate that changes in extracellular calcium result in changes in URE3-BP mRNA and in the ability of URE3-BP to bind to URE3-containing promoters. Modulation of URE3-BP by calcium may represent an important mechanism of control of gene expression in E. histolytica.
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Affiliation(s)
- Carol A Gilchrist
- Department of Internal Medicine, University of Virginia, Charlottesville, Virginia 22908, USA
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Das S, Stevens T, Castillo C, Villasenõr A, Arredondo H, Reddy K. Lipid metabolism in mucous-dwelling amitochondriate protozoa. Int J Parasitol 2002; 32:655-75. [PMID: 12062485 DOI: 10.1016/s0020-7519(02)00006-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Entamoeba, Giardia, and trichomonads are the prominent members of a group known as 'mucosal parasites'. While Entamoeba and Giardia trophozoites colonise the small intestine, trichomonads inhabit the genitourinary tracts of humans and animals. These protozoa lack mitochondria, well-developed Golgi complexes, and other organelles typical of higher eukaryotes. Nonetheless, they have developed unique metabolic pathways that allow them to survive and multiply in the small intestine and reproductive tracts by scavenging nutrients from the host. Various investigators have shown that these protozoa are unable to synthesise the majority of their own lipids and cholesterol de novo; rather, they depend mostly on supplies from outside sources. Therefore, questions of how they transport and utilise exogenous lipids for metabolic purposes are extremely important. There is evidence suggesting that these parasites can take up the lipids and cholesterol they need from lipoprotein particles present in the host and/or in the growth medium. Studies also support the idea that individual lipid and fatty acid molecules can be transported without the help of lipoproteins. Exogenous phospholipids have been shown to undergo fatty acid remodelling (by deacylation/reacylation reactions), which allows these protozoa to alter lipids, bypassing the synthesis of entirely new phospholipid molecules. In addition, many of these amitochondriates are, however, capable of elongating/desaturating long-chain fatty acids, and assembling novel glycophospholipid molecules. In this review, progress in various aspects of lipid research on these organisms is discussed. Attempts are also made to identify steps of lipid metabolic pathways that can be used to develop chemotherapeutic agents against these and other mucosal parasites.
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Affiliation(s)
- Siddhartha Das
- Department of Biological Sciences, University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968-0519, USA.
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Cox JL, Lancaster T, Carlson CG. Changes in the motility of B16F10 melanoma cells induced by alterations in resting calcium influx. Melanoma Res 2002; 12:211-9. [PMID: 12140377 DOI: 10.1097/00008390-200206000-00004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Alterations in the extracellular Ca(2+) or K(+) concentration had significant influences on the motility of B16F10 melanoma cells measured in the absence of exogenous integrins using a conventional Boyden chamber assay. At normal K(+) concentrations, motility increased slightly when the concentration of Ca(2+) was increased 10-fold. At normal Ca(2+) concentrations, motility increased by 290% when the extracellular K(+) concentration was reduced 10-fold (from control of 5.4 mM to 0.54 mM), and increased to 250% of control levels when the K(+) concentration was increased between 30 and 54 mM, but was relatively uninfluenced at K(+) concentrations between 5 and 30 mM. Simultaneous application of low concentrations (20 microM) of GdCl(3) completely prevented the effects of low and high K(+) on motility. Exposure to Gd(3+) or Tb(3+) also produced a flattening of the cells and enhanced cell attachment. Although the steady state intracellular Ca(2+) concentration was not significantly influenced by the K(+) concentration, the resting permeability to divalent cations, determined from Mn(2+) quench rates in fura-loaded cells, was significantly increased by a reduction in the K(+) concentration. These results indicate that resting Ca(2+) influx is critical to the movement of B16F10 melanoma cells, and demonstrate that lanthanides, which block resting Ca(2+) influx pathways, are potent antimotility agents.
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Affiliation(s)
- J L Cox
- Department of Biochemistry, Kirksville Cellege Osteopathic Medicine, Kirksville, MO 63501, USA.
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Silva-Neto MAC, Atella GC, Shahabuddin M. Inhibition of Ca2+/calmodulin-dependent protein kinase blocks morphological differentiation of plasmodium gallinaceum zygotes to ookinetes. J Biol Chem 2002; 277:14085-91. [PMID: 11827960 DOI: 10.1074/jbc.m107903200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Once ingested by mosquitoes, malaria parasites undergo complex cellular changes. These include zygote formation, transformation of zygote to ookinete, and differentiation from ookinete to oocyst. Within the oocyst, the parasite multiplies into numerous sporozoites. Modulators of intracellular calcium homeostasis, MAPTAM, and TMB-8 blocked ookinete development as did the calmodulin (CaM) antagonists W-7 and calmidazolium. Ca(2+)/CaM-dependent protein kinase inhibitor KN-93 also blocked zygote elongation, while its ineffective analog KN-92 did not have such effect. In vitro both zygote and ookinete extracts efficiently phosphorylated autocamtide-2, a classic CaM kinase substrate, which could be blocked by calmodulin antagonists W-7 and calmidazolium and CaM kinase inhibitor KN-93. These results demonstrated the presence of calmodulin-dependent CaM kinase activity in the parasite. KN-93-treated parasites, however, expressed the ookinete-specific enzyme chitinase and the ookinete surface antigen Pgs28 normally, suggesting that the morphologically untransformed parasites are biochemically mature ookinetes. In mosquitoes, KN-93-treated parasites did not develop as oocysts, while KN-92-treated parasites produced similar numbers of oocysts as controls. These data suggested that in Plasmodium gallinaceum morphological development of zygote to ookinete, but not its biochemical maturation, relies on Ca(2+)/CaM-dependent protein kinase activity and demonstrated that the morphological differentiation is essential for the further development of the parasite in infected blood-fed mosquitoes.
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Affiliation(s)
- Mário A C Silva-Neto
- Laboratory of Malaria and Vector Research, NIAID, National Institutes of Health, Bethesda, Maryland 20892-0425, USA
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Atreya HS, Sahu SC, Bhattacharya A, Chary KV, Govil G. NMR derived solution structure of an EF-hand calcium-binding protein from Entamoeba Histolytica. Biochemistry 2001; 40:14392-403. [PMID: 11724551 DOI: 10.1021/bi0114978] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present the three-dimensional (3D) solution structure of a calcium-binding protein from Entamoeba histolytica (EhCaBP), an etiologic agent of amoebiasis affecting millions worldwide. EhCaBP is a 14.7 kDa (134 residues) monomeric protein thought to play a role in the pathogenesis of amoebiasis. The 3D structure of Ca(2+)-bound EhCaBP has been derived using multidimensional nuclear magnetic resonance (NMR) spectroscopic techniques. The study reveals the presence of two globular domains connected by a flexible linker region spanning 8 amino acid residues. Each domain consists of a pair of helix-loop-helix motifs similar to the canonical EF-hand motif of calcium-binding proteins. EhCaBP binds to four Ca(2+) with high affinity (two in each domain), and it is structurally related to calmodulin (CaM) and troponin C (TnC) despite its low sequence homology ( approximately 29%) with these proteins. NMR-derived structures of EhCaBP converge within each domain with low RMSDs and angular order-parameters for backbone torsion angles close to 1.0. However, the presence of a highly flexible central linker region results in an ill-defined orientation of the two domains relative to one other. These findings are supported by backbone (15)N relaxation rate measurements and deuterium exchange studies, which reveal low structural order parameters for residues in the central linker region. Earlier, biochemical studies showed that EhCaBP is involved in a novel signal transduction mechanism, distinct from CaM. A possible reason for such a functional diversity is revealed by a detailed comparison of the 3D structure of EhCaBP with that of CaM and TnC. The studies indicate a more open C-terminal domain for EhCaBP with larger water exposed total hydrophobic surface area as compared to CaM and TnC. Further dissimilarities between the structures include the presence of two Gly residues (G63 and G67) in the central linker region of EhCaBP, which seem to impart it a greater flexibility compared to CaM and TnC and also play crucial role in its biological function. Thus, unlike in CaM and TnC, wherein the length and/or composition of the central linker have been found to be crucial for their function, in EhCaBP, both flexibility as well as amino acid composition is required for the function of the protein.
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Affiliation(s)
- H S Atreya
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai-400005, India
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Bonnet S, Prévot G, Jacques JC, Boudin C, Bourgouin C. Transcripts of the malaria vector Anopheles gambiae that are differentially regulated in the midgut upon exposure to invasive stages of Plasmodium falciparum. Cell Microbiol 2001; 3:449-58. [PMID: 11437831 DOI: 10.1046/j.1462-5822.2001.00128.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Understanding the interactions between the most deadly malaria parasite, Plasmodium falciparum, and its main vector, Anopheles gambiae, would be of great help in developing new malaria control strategies. The malaria parasite undergoes several developmental transitions in the mosquito midgut and suffers population losses to which mosquito factors presumably contribute. To identify such factors, we analysed An. gambiae midgut transcripts whose expression is regulated upon ingestion of invasive or non-invasive forms of P. falciparum using a differential display approach. Sixteen cDNA were studied in detail; 12 represent novel genes of An. gambiae including a gene encoding profilin. Four transcripts were specifically regulated by P. falciparum gametocytes (invasive forms), whereas the others were regulated by either non-invasive or both non-invasive and invasive forms of the parasite. This differential regulation of some genes may reflect the adaptation of P. falciparum to its natural vector. These genes may be involved in the development of P. falciparum in An. gambiae or in the defence reaction of the mosquito midgut towards the parasite.
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Affiliation(s)
- S Bonnet
- Ecologie des Systèmes Vectoriels, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France. IRD-OCEAC, PO Box 288, Yaoundé, Cameroon
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Ortiz D, del Carmen Dominguez-Robles M, Villegas-Sepúlveda N, Meza I. Actin induction during PMA and cAMP-dependent signal pathway activation in Entamoeba histolytica trophozoites. Cell Microbiol 2000; 2:391-400. [PMID: 11207595 DOI: 10.1046/j.1462-5822.2000.00060.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Activation of PKC or cAMP-dependent signalling pathways in Entamoeba histolytica triggers the phosphorylation of proteins involved in actin rearrangements necessary for adhesion and locomotion. Analogous motifs to SRE and CRE sequences--known to respond to PMA and cAMP--were identified within the 5' regulatory region (5'RR) of one of the parasite actin genes. These sequences could be involved in the actin transcriptional upregulation reported during signalling. To test this hypothesis, a plasmid containing the 5'RR of the actin gene fused to the bacterial neomycin gene (neo) was used for stable transfection. Expression of neo and endogenous actin was measured after stimulation of transfected amoebae by PMA and dcAMP. It was found that both compounds induced neo and actin expression and showed a co-operative effect in the induction of neo. Induction by PMA or dcAMP failed if the directing amoebic 5'RR lacked SRE and CRE motifs. Transfection of amoebae with plasmid constructs, containing either progressive deletions of the actin 5'RR or site-directed mutations of the SRE and CRE-like motifs, corroborated that these sequences and a co-ordinated participation of PKC- and PKA-activated transcription factors are responsible for the increments in neo and actin mRNAs. In vivo, these PMA and cAMP-response elements could play an important role in regulating actin expression and organization in signalling processes activated during tissue invasion.
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Affiliation(s)
- D Ortiz
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México, DF, Mexico
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Abstract
In spite of a wealth of knowledge on the biochemistry and cellular and molecular biology of Entamoeba histolytica, little has been done to apply these advances to our understanding of the lesions observed in patients with intestinal amebiasis. In this review, the pathological and histological findings in acute amebic colitis are related to the molecular mechanisms of E. histolytica pathogenicity described to date. Infection of the human colon by E. histolytica produces focal ulceration of the intestinal mucosa, resulting in dysentery (diarrhea with blood and mucus). Although a complete picture has not yet been achieved, the basic mechanisms involved in the production of focal lytic lesions include complex multifactorial processes in which lectins facilitate adhesion, proteases degrade extracellular matrix components, porins help nourish the parasite and may also kill incoming polymorphonuclear leukocytes and macrophages, and motility is used by the parasite to invade deeper layers of the colon. In addition, E. histolytica has developed mechanisms to modulate the immune response during acute infection. Nevertheless, much still needs to be unraveled to understand how this microscopic parasite has earned its well-deserved histolytic name.
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Espinosa-Cantellano M, Martínez-Palomo A. Pathogenesis of intestinal amebiasis: from molecules to disease. Clin Microbiol Rev 2000; 13:318-31. [PMID: 10756002 PMCID: PMC100155 DOI: 10.1128/cmr.13.2.318] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In spite of a wealth of knowledge on the biochemistry and cellular and molecular biology of Entamoeba histolytica, little has been done to apply these advances to our understanding of the lesions observed in patients with intestinal amebiasis. In this review, the pathological and histological findings in acute amebic colitis are related to the molecular mechanisms of E. histolytica pathogenicity described to date. Infection of the human colon by E. histolytica produces focal ulceration of the intestinal mucosa, resulting in dysentery (diarrhea with blood and mucus). Although a complete picture has not yet been achieved, the basic mechanisms involved in the production of focal lytic lesions include complex multifactorial processes in which lectins facilitate adhesion, proteases degrade extracellular matrix components, porins help nourish the parasite and may also kill incoming polymorphonuclear leukocytes and macrophages, and motility is used by the parasite to invade deeper layers of the colon. In addition, E. histolytica has developed mechanisms to modulate the immune response during acute infection. Nevertheless, much still needs to be unraveled to understand how this microscopic parasite has earned its well-deserved histolytic name.
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Meza I. Extracellular matrix-induced signaling in Entamoeba histolytica: its role in invasiveness. PARASITOLOGY TODAY (PERSONAL ED.) 2000; 16:23-8. [PMID: 10637584 DOI: 10.1016/s0169-4758(99)01586-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Entamoeba histolytica trophozoites can invade the mucosa of the host large intestine to cause disease. Here, Isaura Meza describes recent work indicating that the trophozoites respond to the binding of extracellular matrix proteins by activating receptor-mediated signal transduction pathways. Activation of phosphokinase C or adenylyl cyclase induces protein phosphorylation, actin gene expression and reorganization of the actin cytoskeleton to form adhesive structures that promote interaction with the substrate and the release of proteases. The release of proteases at the sites of contact, with the subsequent degradation of the substrate and generation of chemotactic peptides, facilitates locomotion and dissemination of the invading trophozoites.
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Affiliation(s)
- I Meza
- Departamento de Biomedicina Molecular, CINVESTAV del IPN, México, D.F., México.
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Paveto C, Torres HN, Flawia MM, García-Espitia M, Ortega A, Orozco E. Entamoeba histolytica: signaling through G proteins. Exp Parasitol 1999; 91:170-5. [PMID: 9990345 DOI: 10.1006/expr.1998.4361] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The intracellular signaling pathways of Entamoeba histolytica are largely unknown. Although the expression of guanine nucleotide binding proteins (G proteins) is expected from functional studies, their biochemical characterization remains elusive in this protozoan. Using a combination of biochemical and immunological studies, we provide strong evidence for the presence of a Gs protein in amoeba. Our results strengthen our understanding of the signal transduction mechanisms in E. histolytica as potential sites of a new therapeutic strategy.
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Affiliation(s)
- C Paveto
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Buenos Aires, Argentina
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Soid-Raggi LG, Torres-Márquez ME, Meza I. Entamoeba histolytica: identification of functional Gs and Gi proteins as possible signal transduction elements in the interaction of trophozoites with fibronectin. Exp Parasitol 1998; 90:262-9. [PMID: 9806871 DOI: 10.1006/expr.1998.4333] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Trophozoites of Entamoeba histolytica adhere to several components of the extracellular matrix. Binding is mediated by specific receptors identified in the parasite surface. Interaction of trophozoites with FN induces the formation of special adhesion structures that are dynamic cytoskeleton membrane complexes and facilitate both adhesion and substrate degradation. The process requires activation of signaling pathways in which PLC, IP3, Ca2-, and PKC participate. These observations, and recent experiments showing increments in cAMP in the trophozoites during the interaction with FN, suggest that FN receptors in the amebic surface could be coupled to G-proteins. We report here that trophozoite plasma membrane peptides of 92, 49, 42, 37, and 21 kDa are ADP-ribosylated by Vibrio cholerae and Bordetella pertussis toxins. Three of them are also recognized by antibodies prepared against the alpha-subunit of Gs-and Gi-proteins. Adenylyl cyclase activity detected in isolated membranes was strongly stimulated by treatment with the toxins. Forskolin (an agonist of the enzyme) and FN also induced increments in the enzymatic activity. Live amebas incubated with the toxins showed enhanced adhesion to FN substrates and a striking reorganization of polymerized actin. The actin rearrangement is reminiscent of the one induced by either forskolin or dibutyril cyclic AMP treatment. Our present data show the presence and the functionality of Gs- and Gi-like proteins and their apparent activation during in vitro interaction of amebas with FN and complement previous observations indicating the operation of signal transduction mechanisms in E. histolytica.
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Affiliation(s)
- L G Soid-Raggi
- Departamento de Biología Celular, CINVESTAV del IPN, México, D.F., México
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Guillén N, Boquet P, Sansonetti P. The small GTP-binding protein RacG regulates uroid formation in the protozoan parasite Entamoeba histolytica. J Cell Sci 1998; 111 ( Pt 12):1729-39. [PMID: 9601102 DOI: 10.1242/jcs.111.12.1729] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Entamoeba histolytica is a protozoan parasite that invades human intestine leading to ulceration and destruction of tissue. Amoebic movement and phagocytosis of human cells is accompanied by characteristic changes in cell morphology. Amoebae become polarized, developing a frontal pseudopod and a well-defined rear zone of membrane accumulation designated the uroid. In motile eukaryotic cells, a phenomenon that contributes to movement is the capping of receptors at the cell surface. During the capping process, E. histolytica concentrates ligand-receptor complexes in the uroid. Interestingly, some of these surface receptors are involved in the survival of the parasite. While looking for regulators of capping and uroid formation, we identified RacG, an E. histolytica protein that is homologous to human Rac1. This protein belongs to the Rac subfamily of small GTPases implicated in interactions between the actin cytoskeleton and the membrane of mammalian cells. Cloning of the EhracG gene and analysis of the protein activity either in murine fibroblasts or in E. histolytica revealed that EhRacG induces a characteristic Rac phenotype. When expressed in amoebae, an EhRacG-V12 mutant protein not only deregulated cell polarity, but also caused a defect in cytokinesis. Analysis of the cytoskeleton in amoebae bearing this mutant revealed that F-actin concentrated at the periphery of the cell. In addition, the number and localization of uroids were modified. These results suggest a role for EhRacG in amoebic morphogenesis and cytokinesis.
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Affiliation(s)
- N Guillén
- Unité de Pathogénie Microbienne Moléculaire, Institut National de la Santé et de la Recherche Médicale U389 Institut Pasteur, France.
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Silva Filho FC, Ortega-López J, Arroyo R. YIGSR is the preferential laminin-1 residing adhesion sequence for Trichomonas vaginalis. Exp Parasitol 1998; 88:240-2. [PMID: 9562428 DOI: 10.1006/expr.1998.4227] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- F C Silva Filho
- UFRJ-Instituto de Biofísica Carlos Chagas Filho, CCS-Bloco G, Rio de Janeiro, Brazil
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Manning-Cela R, Meza I. Up-regulation of action mRNA and reorganization of the cytoskeleton in Entamoeba histolytica trophozoites. J Eukaryot Microbiol 1997; 44:18-24. [PMID: 9172829 DOI: 10.1111/j.1550-7408.1997.tb05685.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Actin mRNA levels were measured in Entamoeba histolytica trophozoites after experimentally inducing changes in the organization of the cytoskeleton. The treatment of trophozoites with forskolin, N6,2'-O-dibutyryl-adenosine 3':5'-cyclic monophosphate, and phorbol myristate acetate induced the organization of actin into multiple dots and defined structures with a concomitant increase in F-actin content. Cytochalasin D elicited polarization of the structured actin and formation of aggregates, as well as an increment in F-actin. Simultaneously, up-regulation of actin mRNA levels was produced by all the drugs. De novo synthesis of actin mRNA, as measured by nuclear run-ons, showed increased transcription of actin mRNA. On the other hand, treatment of cells with actinomycin D blocked the elevation of actin mRNA synthesis induced by forskolin, dibutyryl cyclic AMP, or cytochalasin D whereas, the increment induced by PMA was not affected. These data indicate a regulatory control of actin mRNA synthesis at the transcriptional level by forskolin, dibutyryl cyclic AMP and cytochalasin D, and transcriptional as well as post-transcriptional controls by phorbol myristate acetate. The experiments presented here suggest the possibility that, regulation of actin mRNA transcription in E. histolytica trophozoites is linked to growth conditions, that are accompanied by reorganization of the actin cytoskeleton and thus, related to the motility and invasiveness of the parasite.
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Affiliation(s)
- R Manning-Cela
- Departamento de Biología Celular, Instituto Politecnico Nacional, México D.F., México
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