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Ansari MA, Nguyen TT, Kocurek KI, Kim WTH, Kim TK, Mulenga A. Recombinant Ixodes scapularis Calreticulin Binds Complement Proteins but Does Not Protect Borrelia burgdorferi from Complement Killing. Pathogens 2024; 13:560. [PMID: 39057787 PMCID: PMC11280304 DOI: 10.3390/pathogens13070560] [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: 04/23/2024] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 07/28/2024] Open
Abstract
Ixodes scapularis is a blood-feeding obligate ectoparasite responsible for transmitting the Lyme disease (LD) agent, Borrelia burgdorferi. During the feeding process, I. scapularis injects B. burgdorferi into the host along with its saliva, facilitating the transmission and colonization of the LD agent. Tick calreticulin (CRT) is one of the earliest tick saliva proteins identified and is currently utilized as a biomarker for tick bites. Our recent findings revealed elevated levels of CRT in the saliva proteome of B. burgdorferi-infected I. scapularis nymphs compared to uninfected ticks. Differential precipitation of proteins (DiffPOP) and LC-MS/MS analyses were used to identify the interactions between Ixs (I. scapularis) CRT and human plasma proteins and further explore its potential role in shielding B. burgdorferi from complement killing. We observed that although yeast-expressed recombinant (r) IxsCRT binds to the C1 complex (C1q, C1r, and C1s), the activator of complement via the classical cascade, it did not inhibit the deposition of the membrane attack complex (MAC) via the classical pathway. Intriguingly, rIxsCRT binds intermediate complement proteins (C3, C5, and C9) and reduces MAC deposition through the lectin pathway. Despite the inhibition of MAC deposition in the lectin pathway, rIxsCRT did not protect a serum-sensitive B. burgdorferi strain (B314/pBBE22Luc) from complement-induced killing. As B. burgdorferi establishes a local dermal infection before disseminating to secondary organs, it is noteworthy that rIxsCRT promotes the replication of B. burgdorferi in culture. We hypothesize that rIxsCRT may contribute to the transmission and/or host colonization of B. burgdorferi by acting as a decoy activator of complement and by fostering B. burgdorferi replication at the transmission site.
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Affiliation(s)
- Moiz Ashraf Ansari
- Department of Veterinary Pathobiology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; (M.A.A.); (T.-T.N.); (W.T.H.K.)
| | - Thu-Thuy Nguyen
- Department of Veterinary Pathobiology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; (M.A.A.); (T.-T.N.); (W.T.H.K.)
| | | | - William Tae Heung Kim
- Department of Veterinary Pathobiology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; (M.A.A.); (T.-T.N.); (W.T.H.K.)
| | - Tae Kwon Kim
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA;
| | - Albert Mulenga
- Department of Veterinary Pathobiology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; (M.A.A.); (T.-T.N.); (W.T.H.K.)
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Jia Z, Yu W, Li J, Zhang M, Zhan B, Yan L, Ming Z, Cheng Y, Tian X, Shao S, Huang J, Zhu X. Crystal structure of Trichinella spiralis calreticulin and the structural basis of its complement evasion mechanism involving C1q. Front Immunol 2024; 15:1404752. [PMID: 38690267 PMCID: PMC11059001 DOI: 10.3389/fimmu.2024.1404752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 05/02/2024] Open
Abstract
Helminths produce calreticulin (CRT) to immunomodulate the host immune system as a survival strategy. However, the structure of helminth-derived CRT and the structural basis of the immune evasion process remains unclarified. Previous study found that the tissue-dwelling helminth Trichinella spiralis produces calreticulin (TsCRT), which binds C1q to inhibit activation of the complement classical pathway. Here, we used x-ray crystallography to resolve the structure of truncated TsCRT (TsCRTΔ), the first structure of helminth-derived CRT. TsCRTΔ was observed to share the same binding region on C1q with IgG based on the structure and molecular docking, which explains the inhibitory effect of TsCRT on C1q-IgG-initiated classical complement activation. Based on the key residues in TsCRTΔ involved in the binding activity to C1q, a 24 amino acid peptide called PTsCRT was constructed that displayed strong C1q-binding activity and inhibited C1q-IgG-initiated classical complement activation. This study is the first to elucidate the structural basis of the role of TsCRT in immune evasion, providing an approach to develop helminth-derived bifunctional peptides as vaccine target to prevent parasite infections or as a therapeutic agent to treat complement-related autoimmune diseases.
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Affiliation(s)
- Zhihui Jia
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Wen Yu
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Jingmo Li
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Mingming Zhang
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Bin Zhan
- Departments of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Liming Yan
- Ministry of Education Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China
| | - Zhenhua Ming
- College of Life Science and Technology, Guangxi University, Nanning, China
| | - Yuli Cheng
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Xiaolin Tian
- Ministry of Education Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China
| | - Shuai Shao
- Beijing institute of Clinical Medicine, Capital Medical University Affiliated Beijing Friendship Hospital, Beijing, China
| | - Jingjing Huang
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Xinping Zhu
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
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Lalnunthangi A, Dakpa G, Tiwari S. Multifunctional role of the ubiquitin proteasome pathway in phagocytosis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 194:179-217. [PMID: 36631192 DOI: 10.1016/bs.pmbts.2022.06.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Phagocytosis is a specialized form of endocytosis where large cells and particles (>0.5μm) are engulfed by the phagocytic cells, and ultimately digested in the phagolysosomes. This process not only eliminates unwanted particles and pathogens from the extracellular sources, but also eliminates apoptotic cells within the body, and is critical for maintenance of tissue homeostasis. It is believed that both endocytosis and phagocytosis share common pathways after particle internalization, but specialized features and differences between these two routes of internalization are also likely. The recruitment and removal of each protein/particle during the maturation of endocytic/phagocytic vesicles has to be tightly regulated to ensure their timely action. Ubiquitin proteasome pathway (UPP), degrades unwanted proteins by post-translational modification of proteins with chains of conserved protein Ubiquitin (Ub), with subsequent recognition of Ub chains by the 26S proteasomes and substrate degradation by this protease. This pathway utilizes different Ub linkages to modify proteins to regulate protein-protein interaction, localization, and activity. Due to its vast number of targets, it is involved in many cellular pathways, including phagocytosis. This chapters describes the basic steps and signaling in phagocytosis and different roles that UPP plays at multiple steps in regulating phagocytosis directly, or through its interaction with other phagosomal proteins. How aberrations in UPP function affect phagocytosis and their association with human diseases, and how pathogens exploit this pathway for their own benefit is also discussed.
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Affiliation(s)
| | | | - Swati Tiwari
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India.
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4
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Corrie L, Gulati M, Awasthi A, Vishwas S, Kaur J, Khursheed R, Porwal O, Alam A, Parveen SR, Singh H, Chellappan DK, Gupta G, Kumbhar P, Disouza J, Patravale V, Adams J, Dua K, Singh SK. Harnessing the dual role of polysaccharides in treating gastrointestinal diseases: As therapeutics and polymers for drug delivery. Chem Biol Interact 2022; 368:110238. [DOI: 10.1016/j.cbi.2022.110238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/27/2022] [Accepted: 10/21/2022] [Indexed: 12/01/2022]
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Díaz-Godínez C, Ríos-Valencia DG, García-Aguirre S, Martínez-Calvillo S, Carrero JC. Immunomodulatory effect of extracellular vesicles from Entamoeba histolytica trophozoites: Regulation of NETs and respiratory burst during confrontation with human neutrophils. Front Cell Infect Microbiol 2022; 12:1018314. [PMID: 36389143 PMCID: PMC9650183 DOI: 10.3389/fcimb.2022.1018314] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 10/10/2022] [Indexed: 08/27/2023] Open
Abstract
Parasites release extracellular vesicles (EVs) which, in some cases, modulate the host's immune response contributing to the establishment of the infection. In this work we have isolated and characterized the EVs released by trophozoites of the human protozoan parasite Entamoeba histolytica, the causal agent of amoebiasis, when alone or in coculture with human neutrophils, and determined their effect on neutrophil NETs and ROS production. Nanoparticle tracking analysis showed that amoebic EVs are variable in size, ranging from less than 50 nm to nearly 600 nm in diameter (average of 167 nm), whereas neutrophil EVs are more uniform in size, with an average of 136 nm. In cocultures amoeba:neutrophil (1:100) most EVs are 98 nm in size, which is the typical size of exosomes. EVs from amoebae and neutrophils showed almost equal levels of ROS, which were considerably increased in EVs from cocultures. Uptake of amoebic EVs by neutrophils was demonstrated by fluorescence and resulted in a significant reduction in the oxidative burst and NET release triggered by PMA, ionophore A23187, or the amoebae itself used as stimuli. Interestingly, uptake of EVs from cocultures did not affect ROS production, but instead caused a greater delay in the onset of NETs release and in their quantity. A comparative proteomic analysis between the EVs of amoebae and neutrophils separately vs the cocultures showed a similar distribution of protein categories in the GO analysis, but differences in the expression and abundance of proteins such as the N-acetyl-D-galactosamine (GalNAc) inhibitable surface lectin and calreticulin in amoeba EVs, and various antimicrobial molecules in neutrophil EVs, such as lactoferrin and myeloperoxidase. These results highlight the importance of EVs in the immunomodulatory effects exerted by amoeba on human neutrophils.
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Affiliation(s)
- César Díaz-Godínez
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
| | - Diana G. Ríos-Valencia
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
| | - Samuel García-Aguirre
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
| | - Santiago Martínez-Calvillo
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, EM, Mexico
| | - Julio César Carrero
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
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Guillen N. Signals and signal transduction pathways in Entamoeba histolytica during the life cycle and when interacting with bacteria or human cells. Mol Microbiol 2020; 115:901-915. [PMID: 33249684 DOI: 10.1111/mmi.14657] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 01/17/2023]
Abstract
Entamoeba histolytica is the etiological agent of amebiasis in humans. This ameba parasite resides as a commensal in the intestine where it shares intestinal resources with the bacterial microbiome. In the intestinal ecosystem, the ameba encysts and eventually develops disease by invading the tissues. E. histolytica possesses cell surface receptors for the proper sensing of signals involved in encystation or sustaining parasite interaction with bacteria and human cells. Among those receptors are the Gal/GalNAc lectin, G protein-coupled receptors, and transmembrane kinases. In addition there are recently discovered, promising proteins, including orthologs of Toll-type receptors and β trefoil lectins. These proteins trigger a wide variety of signal transduction pathways; however, most of the players involved in the signaling pathways evoked in this parasite are unknown. This review provides an overview of amoebic receptors and their role in encystation, adherence to bacteria or human cells, as well as the reported intracellular signal transduction processes that they can trigger. This knowledge is essential for understanding the lifestyle of E. histolytica and its cytopathic effect on bacteria and human cells that are responsible for infection.
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Affiliation(s)
- Nancy Guillen
- Institut Pasteur, Centre National de la Recherche Scientifique, CNRS-ERL9195, Paris, France
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Uddin MJ, Leslie JL, Petri WA. Host Protective Mechanisms to Intestinal Amebiasis. Trends Parasitol 2020; 37:165-175. [PMID: 33502317 PMCID: PMC7840892 DOI: 10.1016/j.pt.2020.09.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/27/2020] [Accepted: 09/28/2020] [Indexed: 12/13/2022]
Abstract
The protozoan parasite Entamoeba histolytica is the causative agent of amebiasis, an infection that manifests as colitis and, in some cases, liver abscess. A better understanding of host protective factors is key to developing an effective remedy. Recently, significant advances have been made in understanding the mechanisms of MUC2 production by goblet cells upon amebic infection, regulation of antimicrobial peptide production by Paneth cells, the interaction of commensal microbiota with immune stimulation, and host genetics in conferring protection from amebiasis. In addition to host pathways that may serve as potential therapeutic targets, significant progress has also been made with respect to development of a vaccine against amebiasis. Here, we aim to highlight the current understanding and knowledge gaps critically.
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Affiliation(s)
- Md Jashim Uddin
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Jhansi L Leslie
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA, USA
| | - William A Petri
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA, USA.
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Hasan MM, Teixeira JE, Lam YW, Huston CD. Coactosin Phosphorylation Controls Entamoeba histolytica Cell Membrane Protrusions and Cell Motility. mBio 2020; 11:e00660-20. [PMID: 32753489 PMCID: PMC7407079 DOI: 10.1128/mbio.00660-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 06/30/2020] [Indexed: 12/12/2022] Open
Abstract
Invasion of the colon wall by Entamoeba histolytica during amoebic dysentery entails migration of trophozoites through tissue layers that are rich in extracellular matrix. Transcriptional silencing of the E. histolytica surface metalloprotease EhMSP-1 produces hyperadherent less-motile trophozoites that are deficient in forming invadosomes. Reversible protein phosphorylation is often implicated in regulation of cell motility and invadosome formation. To identify such intermediaries of the EhMSP-1-silenced phenotype, here we compared the phosphoproteomes of EhMSP-1-silenced and vector control trophozoites by using quantitative tandem mass spectrometry-based proteomics. Six proteins were found to be differentially phosphorylated in EhMSP-1-silenced and control cells, including EhCoactosin, a member of the ADF/cofilin family of actin-binding proteins, which was more frequently phosphorylated at serine 147. Regulated overexpression of wild-type, phosphomimetic, and nonphosphorylatable EhCoactosin variants was used to test if phosphorylation functions in control of E. histolytica actin dynamics. Each of the overexpressed proteins colocalized with F-actin during E. histolytica phagocytosis. Nonetheless, trophozoites overexpressing an EhCoactosin phosphomimetic mutant formed more and poorly coordinated cell membrane protrusions compared to those in control or cells expressing a nonphosphorylatable mutant, while trophozoites overexpressing nonphosphorylatable EhCoactosin were significantly more motile within a model of mammalian extracellular matrix. Therefore, although EhCoactosin's actin-binding ability appeared unaffected by phosphorylation, EhCoactosin phosphorylation helps to regulate amoebic motility. These data help to understand the mechanisms underlying altered adherence and motility in EhMSP-1-silenced trophozoites and lay the groundwork for identifying kinases and phosphatases critical for control of amoebic invasiveness.IMPORTANCE Invasive amoebiasis, caused by the intestinal parasite Entamoeba histolytica, causes life-threatening diarrhea and liver abscesses, but, for unknown reasons, only approximately 10% of E. histolytica infections become symptomatic. A key requirement of invasion is the ability of the parasite to migrate through tissue layers. Here, we systematically looked for differences in protein phosphorylation between control parasites and a previously identified hyperadherent E. histolytica cell line that has reduced motility. We identified EhCoactosin, an actin-binding protein not previously known to be phosphoregulated, as one of the differentially phosphorylated proteins in E. histolytica and demonstrated that EhCoactosin phosphorylation functions in control of cell membrane dynamics and amoebic motility. This and the additional differentially phosphorylated proteins reported lay the groundwork for identifying kinases and phosphatases that regulate tissue invasiveness.
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Affiliation(s)
- Muhammad M Hasan
- Department of Medicine, University of Vermont, Larner College of Medicine, Burlington, Vermont, USA
- Cellular, Molecular, and Biomedical Sciences Graduate Program, University of Vermont, Burlington, Vermont, USA
| | - José E Teixeira
- Department of Medicine, University of Vermont, Larner College of Medicine, Burlington, Vermont, USA
| | - Ying-Wai Lam
- Proteomics Facility, Vermont Genetics Network, University of Vermont, Burlington, Vermont, USA
- Department of Biology, University of Vermont, Burlington, Vermont, USA
| | - Christopher D Huston
- Department of Medicine, University of Vermont, Larner College of Medicine, Burlington, Vermont, USA
- Cellular, Molecular, and Biomedical Sciences Graduate Program, University of Vermont, Burlington, Vermont, USA
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Ramírez-Toloza G, Aguilar-Guzmán L, Valck C, Ferreira VP, Ferreira A. The Interactions of Parasite Calreticulin With Initial Complement Components: Consequences in Immunity and Virulence. Front Immunol 2020; 11:1561. [PMID: 32793217 PMCID: PMC7391170 DOI: 10.3389/fimmu.2020.01561] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/12/2020] [Indexed: 12/17/2022] Open
Abstract
Because of its capacity to increase a physiologic inflammatory response, to stimulate phagocytosis, to promote cell lysis and to enhance pathogen immunogenicity, the complement system is a crucial component of both the innate and adaptive immune responses. However, many infectious agents resist the activation of this system by expressing or secreting proteins with a role as complement regulatory, mainly inhibitory, proteins. Trypanosoma cruzi, the causal agent of Chagas disease, a reemerging microbial ailment, possesses several virulence factors with capacity to inhibit complement at different stages of activation. T. cruzi calreticulin (TcCalr) is a highly-conserved, endoplasmic reticulum-resident chaperone that the parasite translocates to the extracellular environment, where it exerts a variety of functions. Among these functions, TcCalr binds C1, MBL and ficolins, thus inhibiting the classical and lectin pathways of complement at their earliest stages of activation. Moreover, the TcCalr/C1 interaction also mediates infectivity by mimicking a strategy used by apoptotic cells for their removal. More recently, it has been determined that these Calr strategies are also used by a variety of other parasites. In addition, as reviewed elsewhere, TcCalr inhibits angiogenesis, promotes wound healing and reduces tumor growth. Complement C1 is also involved in some of these properties. Knowledge on the role of virulence factors, such as TcCalr, and their interactions with complement components in host-parasite interactions, may lead toward the description of new anti-parasite therapies and prophylaxis.
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Affiliation(s)
- Galia Ramírez-Toloza
- Department of Preventive Veterinary Medicine, Faculty of Veterinary Medicine and Livestock Sciences, University of Chile, Santiago, Chile
| | - Lorena Aguilar-Guzmán
- Department of Pathology, Faculty of Veterinary Medicine and Livestock Sciences, University of Chile, Santiago, Chile
| | - Carolina Valck
- Department of Immunology, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH, United States
| | - Arturo Ferreira
- Department of Immunology, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
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Abstract
Calcium signaling plays a key role in many essential processes in almost all eukaryotic systems. It is believed that it may also be an important signaling system of the protist parasite Entamoeba histolytica. Motility, adhesion, cytolysis, and phagocytosis/trogocytosis are important steps in invasion and pathogenesis of E. histolytica, and Ca2+ signaling is thought to be associated with these processes leading to tissue invasion. There are a large number of Ca2+-binding proteins (CaBPs) in E. histolytica, and a number of these proteins appear to be associated with different steps in pathogenesis. The genome encodes 27 EF-hand–containing CaBPs in addition to a number of other Ca2+-binding domain/motif-containing proteins, which suggest intricate calcium signaling network in this parasite. Unlike other eukaryotes, a typical calmodulin-like protein has not been seen in E. histolytica. Though none of the CaBPs display sequence similarity with a typical calmodulin, extensive structural similarity has been seen in spite of lack of significant functional overlap with that of typical calmodulins. One of the unique features observed in E. histolytica is the identification of CaBPs (EhCaBP1, EhCaBP3) that have the ability to directly bind actin and modulate actin dynamics. Direct interaction of CaBPs with actin has not been seen in any other system. Pseudopod formation and phagocytosis are some of the processes that require actin dynamics, and some of the amoebic CaBPs (EhC2Pk, EhCaBP1, EhCaBP3, EhCaBP5) participate in this process. None of these E. histolytica CaBPs have any homolog in organisms other than different species of Entamoeba, suggesting a novel Ca2+ signaling pathway that has evolved in this genus.
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Affiliation(s)
- Mrigya Babuta
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Sudha Bhattacharya
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Alok Bhattacharya
- Department of Biology, Ashoka University, Sonepat, Haryana, India
- * E-mail:
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Abstract
Calreticulin (CRT) is a pleiotropic and highly conserved molecule that is mainly localized in the endoplasmic reticulum. Recently, CRT has gained special interest for its functions outside the endoplasmic reticulum where it has immunomodulatory properties. CRT translocation to the cell membrane serves as an "eat me" signal and promotes efferocytosis of apoptotic cells and cancer cell removal with completely opposite outcomes. Efferocytosis results in a silenced immune response and homeostasis, while removal of dying cancer cells brought about by anthracycline treatment, ionizing-irradiation or photodynamic therapy results in immunogenic cell death with activation of the innate and adaptive immune responses. In addition, CRT impacts phagocyte activation and cytokine production. The effects of CRT on cytokine production depend on its conformation, species specificity, degree of oligomerization and/or glycosylation, as well as its cellular localization and the molecular partners involved. The controversial roles of CRT in cancer progression and the possible role of the CALR gene mutations in myeloproliferative neoplasms are also addressed. The release of CRT and its influence on the different cells involved during efferocytosis and immunogenic cell death points to additional roles of CRT besides merely acting as an "eat me" signal during apoptosis. Understanding the contribution of CRT in physiological and pathological processes could give us some insight into the potential of CRT as a therapeutic target.
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Ujang J, Sani AAA, Lim BH, Noordin R, Othman N. Analysis of Entamoeba histolytica Membrane Proteome Using Three Extraction Methods. Proteomics 2018; 18:e1700397. [PMID: 30284757 DOI: 10.1002/pmic.201700397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 09/12/2018] [Indexed: 11/09/2022]
Abstract
Entamoeba histolytica membrane proteins are important players toward the pathogenesis of amoebiasis, but the roles of most of the proteins are not fully understood. Since efficient protein extraction method is crucial for a successful MS analysis, three extractions methods are evaluated for the use in studying the membrane proteome of E. histolytica: Two commercial kits (ProteoExtract from Calbiochem and ProteoPrep from Sigma), and a conventional laboratory method. The results show that ProteoExtract and the conventional method gave higher protein yields compared to ProteoPrep. LC-ESI-MS/MS identifies 456, 482, and 551 membrane fraction proteins extracted using ProteoExtract, ProteoPrep, and a conventional method, respectively. In silico analysis predicts 108 (21%), 235 (45%), and 177 (34%) membrane proteins from the extracts of ProteoExtract, ProteoPrep, and the conventional method, respectively. Furthermore, analysis of the cytosolic and membrane fractions shows the highest selectivity of the membrane proteins using the ProteoPrep extraction kit. Overall, this study reports 828 E. histolytica membrane fraction proteins that include 249 predicted membrane proteins. The data are available via ProteomeXchange with identifier PXD010171.
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Affiliation(s)
- Jorim Ujang
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800, Penang, Malaysia
| | - Asmahani Azira Abdu Sani
- Malaysia Genome Institute, National Institutes of Biotechnology Malaysia (NIBM), Jalan Bangi, 43400, Kajang, Selangor Darul Ehsan, Malaysia
| | - Boon Huat Lim
- School of Health Sciences, Universiti Sains Malaysia, 16150, Kelantan, Malaysia
| | - Rahmah Noordin
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800, Penang, Malaysia
| | - Nurulhasanah Othman
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800, Penang, Malaysia
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Gonzalez Rivas E, Ximenez C, Nieves-Ramirez ME, Moran Silva P, Partida-Rodríguez O, Hernandez EH, Rojas Velázquez L, Serrano Vázquez A, Magaña Nuñez U. Entamoeba histolytica Calreticulin Induces the Expression of Cytokines in Peripheral Blood Mononuclear Cells Isolated From Patients With Amebic Liver Abscess. Front Cell Infect Microbiol 2018; 8:358. [PMID: 30406037 PMCID: PMC6202884 DOI: 10.3389/fcimb.2018.00358] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 09/19/2018] [Indexed: 12/26/2022] Open
Abstract
Calreticulin (CRT) is a highly conserved protein in the endoplasmic reticulum that plays important roles in the regulation of key cellular functions. Little is known about the participation of E. histolytica CRT (EhCRT) in the processes of pathogenicity or in the modulation of the host immune response. The aim of this study was to evaluate the role of CRT in the proliferation and the cytokine profile in peripheral blood mononuclear cells (PBMCs) from patients with amebic liver abscess (ALA) during the acute phase (AP-ALA) of the disease compared to patients during the resolution phase (R-ALA). The PBMCs from each participant were cocultured with EhCRT and tested by the colorimetric method to evaluate their proliferation index (PI). The supernatants were subjected to an enzyme-linked immunosorbent assay (ELISA) to evaluate the concentration of cytokines. The mean values of all groups were compared using the independent t-test. When the PIs of individuals without diagnosis of liver abscess (NEG) were compared, there were no statistically significant differences in the proliferation of PBMCs between patients with AP-ALA and R-ALA when stimulated with EhCRT or concanavalin A (ConA). However, the levels of interleukins [IL-6, IL-10, granulocyte colony stimulating factor (GCSF), and transforming growth factor β1 (TGFβ1)] were higher in patients with AP-ALA, whereas in patients with R-ALA, higher levels of interferon gamma (IFNγ) were detected. These results suggest that EhCRT acts as a mitogen very similar to the activity of ConA. In addition, EhCRT is an excellent immunogen for the specific activation of PBMCs, inducing the differential expression of ILs depending on the outcome of disease, determining the type of immune response: a Th2 cytokine profile during the acute phase and a Th1 profile during the resolution phase.
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Affiliation(s)
- Enrique Gonzalez Rivas
- Laboratorio de Inmunología, Unidad de Investigación de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
| | - Cecilia Ximenez
- Laboratorio de Inmunología, Unidad de Investigación de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
| | - Miriam Enriqueta Nieves-Ramirez
- Laboratorio de Inmunología, Unidad de Investigación de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
| | - Patricia Moran Silva
- Laboratorio de Inmunología, Unidad de Investigación de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
| | - Oswaldo Partida-Rodríguez
- Laboratorio de Inmunología, Unidad de Investigación de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
| | - Eric Hernandez Hernandez
- Laboratorio de Inmunología, Unidad de Investigación de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
| | - Liliana Rojas Velázquez
- Laboratorio de Inmunología, Unidad de Investigación de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
| | - Angelica Serrano Vázquez
- Laboratorio de Inmunología, Unidad de Investigación de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
| | - Ulises Magaña Nuñez
- Laboratorio de Inmunología, Unidad de Investigación de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
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14
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Verma K, Srivastava VK, Datta S. Rab GTPases take centre stage in understanding Entamoeba histolytica biology. Small GTPases 2018; 11:320-333. [PMID: 30273093 DOI: 10.1080/21541248.2018.1528840] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Rab GTPases constitute the largest subgroup in the Ras superfamily of GTPases. It is well established that different Rab GTPases are localized in discrete subcellular localization and regulate the membrane trafficking in nearly all eukaryotic cells. Rab GTPase diversity is often regarded as an expression of vesicular trafficking complexity. The pathogenic amoeba Entamoeba histolytica harbours 91 Rab GTPases which is the highest among the currently available genome sequences from the eukaryotic kingdom. Here, we review the current status of amoebic Rab GTPases diversity, unique biochemical and structural features and summarise their predicted regulators. We discuss how amoebic Rab GTPases are involved in cellular processes such as endocytosis, phagocytosis, and invasion of host cellular components, which are essential for parasite survival and virulence.
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Affiliation(s)
- Kuldeep Verma
- Institute of Science, Nirma University , Ahmedabad, Gujarat, India.,Regional Centre for Biotechnology, NCR Biotech Science Cluster , Faridabad, India
| | | | - Sunando Datta
- Department of Biological Science, Indian Institute of Science Education and Research Bhopal , Bhauri, India
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15
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Cornick S, Chadee K. Entamoeba histolytica: Host parasite interactions at the colonic epithelium. Tissue Barriers 2018; 5:e1283386. [PMID: 28452682 DOI: 10.1080/21688370.2017.1283386] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Entamoeba histolytica (Eh) is the protozoan parasite responsible for intestinal amebiasis and interacts dynamically with the host intestinal epithelium during disease pathogenesis. A multifaceted pathogenesis profile accounts for why 90% of individuals infected with Eh are largely asymptomatic. For 100 millions individuals that are infected each year, key interactions within the intestinal mucosa dictate disease susceptibility. The ability for Eh to induce amebic colitis and disseminate into extraintestinal organs depends on the parasite competing with indigenous bacteria and overcoming the mucus barrier, binding to host cells inducing their cell death, invasion through the mucosa and outsmarting the immune system. In this review we summarize how Eh interacts with the intestinal epithelium and subverts host defense mechanisms in disease pathogenesis.
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Affiliation(s)
- Steve Cornick
- a Department of Microbiology, Immunology and Infectious Diseases , Snyder Institute for Chronic Diseases, University of Calgary , Calgary , Alberta , Canada
| | - Kris Chadee
- a Department of Microbiology, Immunology and Infectious Diseases , Snyder Institute for Chronic Diseases, University of Calgary , Calgary , Alberta , Canada
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16
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Kumari R, Gupta P, Tiwari S. Ubc7/Ube2g2 ortholog in Entamoeba histolytica: connection with the plasma membrane and phagocytosis. Parasitol Res 2018; 117:1599-1611. [PMID: 29594345 DOI: 10.1007/s00436-018-5842-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 03/15/2018] [Indexed: 12/13/2022]
Abstract
Endoplasmic reticulum (ER)-associated degradation (ERAD) and unfolded protein response (UPR) pathways are important for quality and quantity control of membrane and secretory proteins. We have identified orthologs of ER-associated ubiquitin conjugating enzymes (E2s) Ubc6/Ube2j2 and Ubc7/Ube2g2, ubiquitin ligases (E3) Hrd1 and GP78/AMFR, and sensor of UPR, Ire1 in E. histolytica that show conservation of important features of these proteins. Biochemical characterization of the ortholog of ERAD E2, Ubc7/Ube2g2 (termed as EhUbc7), was carried out. This E2 was transcriptionally upregulated several folds upon induction of UPR with tunicamycin. Ire1 ortholog was also upregulated upon UPR induction suggesting a linked UPR and ERAD pathway in this organism. EhUbc7 showed enzymatic activity and, similar to its orthologs in higher eukaryotes, formed polyubiquitin chains in vitro and localized to both cytoplasm and membranes. However, unlike its ortholog in higher eukaryotes, it also showed localization to the plasma membrane along with calreticulin. Inactivation of EhUbc7 significantly inhibited erythrophagocytosis, suggesting a novel function that has not been reported before for this E2. No change in growth, motility, or cell-surface expression of Gal/GalNAC lectin was observed due to inactivation of EhUbc7. The protein was present in the phagocytic cups but not in the phagosomes. A significant decrease in the number of phagocytic cups in inactive EhUbc7 expressing cells was observed, suggesting altered kinetics of phagocytosis. These findings have implications for evolutionary and mechanistic understanding of connection between phagocytosis and ER-associated proteins.
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Affiliation(s)
- Rinki Kumari
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Preeti Gupta
- Microbiology Division, Defence Research and Development Establishment, Jhansi Road, Gwalior, MP, 474002, India
| | - Swati Tiwari
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.
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17
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Ximénez C, González E, Nieves M, Magaña U, Morán P, Gudiño-Zayas M, Partida O, Hernández E, Rojas-Velázquez L, García de León MC, Maldonado H. Differential expression of pathogenic genes of Entamoeba histolytica vs E. dispar in a model of infection using human liver tissue explants. PLoS One 2017; 12:e0181962. [PMID: 28771523 PMCID: PMC5542602 DOI: 10.1371/journal.pone.0181962] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 07/10/2017] [Indexed: 12/20/2022] Open
Abstract
We sought to establish an ex vivo model for examining the interaction of E. histolytica with human tissue, using precision-cut liver slices (PCLS) from donated organs. E. histolytica- or E. dispar-infected PCLS were analyzed at different post-infection times (0, 1, 3, 24 and 48 h) to evaluate the relation between tissue damage and the expression of genes associated with three factors: a) parasite survival (peroxiredoxin, superoxide dismutase and 70 kDa heat shock protein), b) parasite virulence (EhGal/GalNAc lectin, amoebapore, cysteine proteases and calreticulin), and c) the host inflammatory response (various cytokines). Unlike E. dispar (non-pathogenic), E. histolytica produced some damage to the structure of hepatic parenchyma. Overall, greater expression of virulence genes existed in E. histolytica-infected versus E. dispar-infected tissue. Accordingly, there was an increased expression of EhGal/GalNAc lectin, Ehap-a and Ehcp-5, Ehcp-2, ehcp-1 genes with E. histolytica, and a decreased or lack of expression of Ehcp-2, and Ehap-a genes with E. dispar. E. histolytica-infected tissue also exhibited an elevated expression of genes linked to survival, principally peroxiredoxin, superoxide dismutase and Ehhsp-70. Moreover, E. histolytica-infected tissue showed an overexpression of some genes encoding for pro-inflammatory interleukins (ILs), such as il-8, ifn-γ and tnf-α. Contrarily, E. dispar-infected tissue displayed higher levels of il-10, the gene for the corresponding anti-inflammatory cytokine. Additionally, other genes were investigated that are important in the host-parasite relationship, including those encoding for the 20 kDa heat shock protein (HSP-20), the AIG-1 protein, and immune dominant variable surface antigen, as well as for proteins apparently involved in mechanisms for the protection of the trophozoites in different environments (e.g., thioredoxin-reductase, oxido-reductase, and 9 hypothetical proteins). Some of the hypothetical proteins evidenced interesting overexpression rates, however we should wait to their characterization. This finding suggest that the present model could be advantageous for exploring the complex interaction between trophozoites and hepatocytes during the development of ALA, particularly in the initial stages of infection.
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Affiliation(s)
- Cecilia Ximénez
- Laboratory of Immunology, Unit of Experimental Medicine, Faculty of Medicine, UNAM, México City, México
- * E-mail:
| | - Enrique González
- Laboratory of Immunology, Unit of Experimental Medicine, Faculty of Medicine, UNAM, México City, México
| | - Miriam Nieves
- Laboratory of Immunology, Unit of Experimental Medicine, Faculty of Medicine, UNAM, México City, México
| | - Ulises Magaña
- Laboratory of Immunology, Unit of Experimental Medicine, Faculty of Medicine, UNAM, México City, México
| | - Patricia Morán
- Laboratory of Immunology, Unit of Experimental Medicine, Faculty of Medicine, UNAM, México City, México
| | - Marco Gudiño-Zayas
- Laboratory of Immunology, Unit of Experimental Medicine, Faculty of Medicine, UNAM, México City, México
| | - Oswaldo Partida
- Laboratory of Immunology, Unit of Experimental Medicine, Faculty of Medicine, UNAM, México City, México
| | - Eric Hernández
- Laboratory of Immunology, Unit of Experimental Medicine, Faculty of Medicine, UNAM, México City, México
| | - Liliana Rojas-Velázquez
- Laboratory of Immunology, Unit of Experimental Medicine, Faculty of Medicine, UNAM, México City, México
| | | | - Héctor Maldonado
- Sub direction of Pathology, National Institute of Cancerology, México City, México
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18
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Hooshmand MJ, Nguyen HX, Piltti KM, Benavente F, Hong S, Flanagan L, Uchida N, Cummings BJ, Anderson AJ. Neutrophils Induce Astroglial Differentiation and Migration of Human Neural Stem Cells via C1q and C3a Synthesis. THE JOURNAL OF IMMUNOLOGY 2017; 199:1069-1085. [PMID: 28687659 DOI: 10.4049/jimmunol.1600064] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/31/2017] [Indexed: 12/23/2022]
Abstract
Inflammatory processes play a key role in pathophysiology of many neurologic diseases/trauma, but the effect of immune cells and factors on neurotransplantation strategies remains unclear. We hypothesized that cellular and humoral components of innate immunity alter fate and migration of human neural stem cells (hNSC). In these experiments, conditioned media collected from polymorphonuclear leukocytes (PMN) selectively increased hNSC astrogliogenesis and promoted cell migration in vitro. PMN were shown to generate C1q and C3a; exposure of hNSC to PMN-synthesized concentrations of these complement proteins promoted astrogliogenesis and cell migration. Furthermore, in vitro, Abs directed against C1q and C3a reversed the fate and migration effects observed. In a proof-of-concept in vivo experiment, blockade of C1q and C3a transiently altered hNSC migration and reversed astroglial fate after spinal cord injury. Collectively, these data suggest that modulation of the innate/humoral inflammatory microenvironment may impact the potential of cell-based therapies for recovery and repair following CNS pathology.
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Affiliation(s)
- Mitra J Hooshmand
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697; .,Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA 92697.,Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92697
| | - Hal X Nguyen
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697.,Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA 92697.,Department of Physical Medicine and Rehabilitation, University of California, Irvine, Irvine, CA 92697
| | - Katja M Piltti
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697.,Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA 92697.,Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92697
| | - Francisca Benavente
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697.,Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA 92697.,Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92697
| | - Samuel Hong
- Bridges to Stem Cell Research Program, California State University, Fullerton, Fullerton, CA 92834; and
| | - Lisa Flanagan
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA 92697
| | | | - Brian J Cummings
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697.,Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA 92697.,Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92697.,Department of Physical Medicine and Rehabilitation, University of California, Irvine, Irvine, CA 92697
| | - Aileen J Anderson
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697.,Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA 92697.,Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92697.,Department of Physical Medicine and Rehabilitation, University of California, Irvine, Irvine, CA 92697
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19
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Moreau C, Cioci G, Iannello M, Laffly E, Chouquet A, Ferreira A, Thielens NM, Gaboriaud C. Structures of parasite calreticulins provide insights into their flexibility and dual carbohydrate/peptide-binding properties. IUCRJ 2016; 3:408-419. [PMID: 27840680 PMCID: PMC5094443 DOI: 10.1107/s2052252516012847] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/09/2016] [Indexed: 06/06/2023]
Abstract
Calreticulin (CRT) is a multifaceted protein, initially discovered as an endoplasmic reticulum (ER) chaperone protein, that is essential in calcium metabolism. Various implications in cancer, early development and immunology have been discovered more recently for CRT, as well as its role as a dominant 'eat-me' prophagocytic signal. Intriguingly, cell-surface exposure/secretion of CRT is among the infective strategies used by parasites such as Trypanosoma cruzi, Entamoeba histolytica, Taenia solium, Leishmania donovani and Schistosoma mansoni. Because of the inherent flexibility of CRTs, their analysis by X-ray crystallography requires the design of recombinant constructs suitable for crystallization, and thus only the structures of two very similar mammalian CRT lectin domains are known. With the X-ray structures of two distant parasite CRTs, insights into species structural determinants that might be harnessed to fight against the parasites without affecting the functions of the host CRT are now provided. Moreover, although the hypothesis that CRT can exhibit both open and closed conformations has been proposed in relation to its chaperone function, only the open conformation has so far been observed in crystal structures. The first evidence is now provided of a complex conformational transition with the junction reoriented towards P-domain closure. SAXS experiments also provided additional information about the flexibility of T. cruzi CRT in solution, thus complementing crystallographic data on the open conformation. Finally, regarding the conserved lectin-domain structure and chaperone function, evidence is provided of its dual carbohydrate/protein specificity and a new scheme is proposed to interpret such unusual substrate-binding properties. These fascinating features are fully consistent with previous experimental observations, as discussed considering the broad spectrum of CRT sequence conservations and differences.
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Affiliation(s)
- Christophe Moreau
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Gianluca Cioci
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Marina Iannello
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Emmanuelle Laffly
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Anne Chouquet
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Arturo Ferreira
- Program of Immunology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, University of Chile, Santiago, Chile
| | - Nicole M. Thielens
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Christine Gaboriaud
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
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20
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Evaluation of the immunodiagnostic potential of a recombinant surface protein domain from Acanthamoeba castellanii. Parasitology 2016; 143:1656-64. [PMID: 27430295 DOI: 10.1017/s0031182016001281] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Acanthamoeba spp. are free-living protists widely distributed in environment, able to cause keratitis, encephalitis and skin lesions in humans and animals. Acanthamoeba spp. exist in two forms: an infective trophozoite and a dormant cyst. Several factors contribute to the pathogenesis of Acanthamoeba spp. The parasite adhesion to the host cell is the primary step for infection and is mediated by a mannose binding-protein, expressed in the surface and considered the main pathogenicity factor in Acanthamoeba spp. So far, there was no evidence of another surface protein of Acanthamoeba spp. relevant for host invasion or infection by these organisms. The aims of this study were to identify and characterize an Acanthamoeba castellanii surface protein and to evaluate its diagnostic potential. In silico predictions of surface proteins allowed to identify the A. castellanii calreticulin as a possible surface antigen. The coding sequence of a predicted extracellular domain of A. castellanii calreticulin was cloned by in vivo homologous recombination and the recombinant polypeptide (AcCRT29-130) was produced. Its immunodiagnostic potential was assessed in a recombinant antigen-based ELISA with sera from experimentally infected rats that developed keratitis and encephalitis, and sera from patients with encephalitis. The AcCRT29-130 was significantly more recognized by sera from encephalitis infected rats in comparison with the non-infected controls. Human sera from encephalitis patients, however presented no significant response. These results showed the AcCRT29-130 potential for A. castellanii infection immunodiagnosis in animals, with further studies being required for assessment of its use for human infections.
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21
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Nakada-Tsukui K, Nozaki T. Immune Response of Amebiasis and Immune Evasion by Entamoeba histolytica. Front Immunol 2016; 7:175. [PMID: 27242782 PMCID: PMC4863898 DOI: 10.3389/fimmu.2016.00175] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 04/20/2016] [Indexed: 12/27/2022] Open
Abstract
Entamoeba histolytica is a protozoan parasite and the causative agent of amebiasis. It is estimated approximately 1% of humans are infected with E. histolytica, resulting in an estimate of 100,000 deaths annually. Clinical manifestations of amebic infection range widely from asymptomatic to severe symptoms, including dysentery and extra-intestinal abscesses. Like other infectious diseases, it is assumed that only ~20% of infected individuals develop symptoms, and genetic factors of both the parasite and humans as well as the environmental factors, e.g., microbiota, determine outcome of infection. There are multiple essential steps in amebic infection: degradation of and invasion into the mucosal layer, adherence to the intestinal epithelium, invasion into the tissues, and dissemination to other organs. While the mechanisms of invasion and destruction of the host tissues by the amebae during infection have been elucidated at the molecular levels, it remains largely uncharacterized how the parasite survive in the host by evading and attacking host immune system. Recently, the strategies for immune evasion by the parasite have been unraveled, including immunomodulation to suppress IFN-γ production, elimination of immune cells and soluble immune mediators, and metabolic alterations against reactive oxygen and nitrogen species to fend off the attack from immune system. In this review, we summarized the latest knowledge on immune reaction and immune evasion during amebiasis.
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Affiliation(s)
- Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases , Tokyo , Japan
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan; Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
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22
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Kim TK, Ibelli AMG, Mulenga A. Amblyomma americanum tick calreticulin binds C1q but does not inhibit activation of the classical complement cascade. Ticks Tick Borne Dis 2016; 6:91-101. [PMID: 25454607 DOI: 10.1016/j.ttbdis.2014.10.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/08/2014] [Accepted: 10/13/2014] [Indexed: 01/02/2023]
Abstract
In this study we characterized Amblyomma americanum (Aam) tick calreticulin (CRT) homolog in tick feeding physiology. In nature, different tick species can be found feeding on the same animal host. This suggests that different tick species found feeding on the same host can modulate the same host anti-tick defense pathways to successfully feed. From this perspective it's plausible that different tick species can utilize universally conserved proteins such as CRT to regulate and facilitate feeding. CRT is a multi-functional protein found in most taxa that is injected into the vertebrate host during tick feeding. Apart from it's current use as a biomarker for human tick bites, role(s) of this protein in tick feeding physiology have not been elucidated. Here we show that annotated functional CRT amino acid motifs are well conserved in tick CRT. However our data show that despite high amino acid identity levels to functionally characterized CRT homologs in other organisms, AamCRT is apparently functionally different. Pichia pastoris expressed recombinant (r) AamCRT bound C1q, the first component of the classical complement system, but it did not inhibit activation of this pathway. This contrast with reports of other parasite CRT that inhibited activation of the classical complement pathway through sequestration of C1q. Furthermore rAamCRT did not bind factor Xa in contrast to reports of parasite CRT binding factor Xa, an important protease in the blood clotting system. Consistent with this observation, rAamCRT did not affect plasma clotting or platelet aggregation. We discuss our findings in the context of tick feeding physiology.
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Affiliation(s)
- Tae Kwon Kim
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, United States
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23
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Hanadate Y, Saito-Nakano Y, Nakada-Tsukui K, Nozaki T. Endoplasmic reticulum-resident Rab8A GTPase is involved in phagocytosis in the protozoan parasite Entamoeba histolytica. Cell Microbiol 2016; 18:1358-73. [PMID: 26807810 PMCID: PMC5071775 DOI: 10.1111/cmi.12570] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 12/31/2015] [Accepted: 01/19/2016] [Indexed: 12/20/2022]
Abstract
Phagocytosis is indispensable for the pathogenesis of the intestinal protozoan parasite Entamoeba histolytica. Here, we showed that in E. histolytica Rab8A, which is generally involved in trafficking from the trans‐Golgi network to the plasma membrane in other organisms but was previously identified in phagosomes of the amoeba in the proteomic analysis, primarily resides in the endoplasmic reticulum (ER) and participates in phagocytosis. We demonstrated that down‐regulation of EhRab8A by small antisense RNA‐mediated transcriptional gene silencing remarkably reduced adherence and phagocytosis of erythrocytes, bacteria and carboxylated latex beads. Surface biotinylation followed by SDS‐PAGE analysis revealed that the surface expression of several proteins presumably involved in target recognition was reduced in the EhRab8A gene‐silenced strain. Further, overexpression of wild‐type EhRab8A augmented phagocytosis, whereas expression of the dominant‐negative form of EhRab8A resulted in reduced phagocytosis. These results indicated that EhRab8A regulates transport of surface receptor(s) for the prey from the ER to the plasma membrane. To our knowledge, this is the first report that the ER‐resident Rab GTPase is involved in phagocytosis through the regulation of trafficking of a surface receptor, supporting a premise of direct involvement of the ER in phagocytosis.
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Affiliation(s)
- Yuki Hanadate
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan
| | - Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. .,Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan.
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Knockdown of Five Genes Encoding Uncharacterized Proteins Inhibits Entamoeba histolytica Phagocytosis of Dead Host Cells. Infect Immun 2016; 84:1045-1053. [PMID: 26810036 DOI: 10.1128/iai.01325-15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/15/2016] [Indexed: 12/17/2022] Open
Abstract
Entamoeba histolytica is the protozoan parasite that causes invasive amebiasis, which is endemic to many developing countries and characterized by dysentery and liver abscesses. The virulence of E. histolytica correlates with the degree of host cell engulfment, or phagocytosis, and E. histolytica phagocytosis alters amebic gene expression in a feed-forward manner that results in an increased phagocytic ability. Here, we used a streamlined RNA interference screen to silence the expression of 15 genes whose expression was upregulated in phagocytic E. histolytica trophozoites to determine whether these genes actually function in the phagocytic process. When five of these genes were silenced, amebic strains with significant decreases in the ability to phagocytose apoptotic host cells were produced. Phagocytosis of live host cells, however, was largely unchanged, and the defects were surprisingly specific for phagocytosis. Two of the five encoded proteins, which we named E. histolytica ILWEQ (EhILWEQ) and E. histolytica BAR (EhBAR), were chosen for localization via SNAP tag labeling and localized to the site of partially formed phagosomes. Therefore, both EhILWEQ and EhBAR appear to contribute to E. histolytica virulence through their function in phagocytosis, and the large proportion (5/15 [33%]) of gene-silenced strains with a reduced ability to phagocytose host cells validates the previously published microarray data set demonstrating feed-forward control of E. histolytica phagocytosis. Finally, although only limited conclusions can be drawn from studies using the virulence-deficient G3 Entamoeba strain, the relative specificity of the defects induced for phagocytosis of apoptotic cells but not healthy cells suggests that cell killing may play a rate-limiting role in the process of Entamoeba histolytica host cell engulfment.
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Ralston KS. Chew on this: amoebic trogocytosis and host cell killing by Entamoeba histolytica. Trends Parasitol 2015; 31:442-52. [PMID: 26070402 DOI: 10.1016/j.pt.2015.05.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 05/04/2015] [Accepted: 05/05/2015] [Indexed: 01/23/2023]
Abstract
Entamoeba histolytica was named 'histolytica' (from histo-, 'tissue'; lytic-, 'dissolving') for its ability to destroy host tissues. Direct killing of host cells by the amoebae is likely to be the driving factor that underlies tissue destruction, but the mechanism was unclear. We recently showed that, after attaching to host cells, amoebae bite off and ingest distinct host cell fragments, and that this contributes to cell killing. We review this process, termed 'amoebic trogocytosis' (trogo-, 'nibble'), and how this process interplays with phagocytosis, or whole cell ingestion, in this organism. 'Nibbling' processes have been described in other microbes and in multicellular organisms. The discovery of amoebic trogocytosis in E. histolytica may also shed light on an evolutionarily conserved process for intercellular exchange.
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Affiliation(s)
- Katherine S Ralston
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA.
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Radulović ŽM, Kim TK, Porter LM, Sze SH, Lewis L, Mulenga A. A 24-48 h fed Amblyomma americanum tick saliva immuno-proteome. BMC Genomics 2014; 15:518. [PMID: 24962723 PMCID: PMC4099483 DOI: 10.1186/1471-2164-15-518] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 06/12/2014] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Multiple tick saliva proteins, the majority of which are unknown, confer tick resistance in repeatedly infested animals. The objective of this study was to identify the 24-48 h fed Amblyomma americanum tick saliva immuno-proteome. The 24-48 h tick-feeding phase is critical to tick parasitism as it precedes important events in tick biology, blood meal feeding and disease agent transmission. Fed male, 24 and 96 h fed female phage display cDNA expression libraries were biopanned using rabbit antibodies to 24 and 48 h fed A. americanum female tick saliva proteins. Biopanned immuno-cDNA libraries were subjected to next generation sequencing, de novo assembly, and bioinformatic analysis. RESULTS More than 800 transcripts that code for 24-48 h fed A. americanum immuno-proteins are described. Of the 895 immuno-proteins, 52% (464/895) were provisionally identified based on matches in GenBank. Of these, ~19% (86/464) show high level of identity to other tick hypothetical proteins, and the rest include putative proteases (serine, cysteine, leukotriene A-4 hydrolase, carboxypeptidases, and metalloproteases), protease inhibitors (serine and cysteine protease inhibitors, tick carboxypeptidase inhibitor), and transporters and/or ligand binding proteins (histamine binding/lipocalin, fatty acid binding, calreticulin, hemelipoprotein, IgG binding protein, ferritin, insulin-like growth factor binding proteins, and evasin). Others include enzymes (glutathione transferase, cytochrome oxidase, protein disulfide isomerase), ribosomal proteins, and those of miscellaneous functions (histamine release factor, selenoproteins, tetraspanin, defensin, heat shock proteins). CONCLUSIONS Data here demonstrate that A. americanum secretes a complex cocktail of immunogenic tick saliva proteins during the first 24-48 h of feeding. Of significance, previously validated immunogenic tick saliva proteins including AV422 protein, calreticulin, histamine release factor, histamine binding/lipocalins, selenoproteins, and paramyosin were identified in this screen, supporting the specificity of the approach in this study. While descriptive, this study opens opportunities for in-depth tick feeding physiology studies.
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Affiliation(s)
- Željko M Radulović
- />Department of Entomology, AgriLife Research, Texas A & M University, 2475 TAMU, College Station, TX77843 USA
| | - Tae K Kim
- />Department of Entomology, AgriLife Research, Texas A & M University, 2475 TAMU, College Station, TX77843 USA
| | - Lindsay M Porter
- />Department of Entomology, AgriLife Research, Texas A & M University, 2475 TAMU, College Station, TX77843 USA
| | - Sing-Hoi Sze
- />Department of Computer Sciences and Engineering, Texas A & M University, College Station, TX77843 USA
- />Department of Biochemistry & Biophysics, Texas A & M University, College Station, TX77843 USA
| | - Lauren Lewis
- />Department of Entomology, AgriLife Research, Texas A & M University, 2475 TAMU, College Station, TX77843 USA
| | - Albert Mulenga
- />Department of Entomology, AgriLife Research, Texas A & M University, 2475 TAMU, College Station, TX77843 USA
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Abstract
Entamoeba histolytica is the third-leading cause of parasitic mortality globally. E. histolytica infection generally does not cause symptoms, but the parasite has potent pathogenic potential. The origins, benefits, and triggers of amoebic virulence are complex. Amoebic pathogenesis entails depletion of the host mucosal barrier, adherence to the colonic lumen, cytotoxicity, and invasion of the colonic epithelium. Parasite damage results in colitis and, in some cases, disseminated disease. Both host and parasite genotypes influence the development of disease, as do the regulatory responses they govern at the host-pathogen interface. Host environmental factors determine parasite transmission and shape the colonic microenvironment E. histolytica infects. Here we highlight research that illuminates novel links between host, parasite, and environmental factors in the regulation of E. histolytica virulence.
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Affiliation(s)
- Chelsea Marie
- Division of Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, Virginia 22908; ,
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Novel distribution of calreticulin to cardiomyocyte mitochondria and its increase in a rat model of dilated cardiomyopathy. Biochem Biophys Res Commun 2014; 449:62-8. [PMID: 24813996 DOI: 10.1016/j.bbrc.2014.04.156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Accepted: 04/29/2014] [Indexed: 11/21/2022]
Abstract
BACKGROUND Calreticulin (CRT), a Ca(2+)-binding chaperone of the endoplasmic reticulum, can also be found in several other locations including the cytosol, nucleus, secretory granules, the outer side of the plasma membrane, and the extracellular matrix. Whether CRT is localized at mitochondria of cardiomyocytes and whether such localization is affected under DCM are still unclear. METHODS AND RESULTS The DCM model was generated in rats by the daily oral administration of furazolidone for thirty weeks. Echocardiographic and hemodynamic studies demonstrated enlarged left ventricular dimensions and reduced systolic and diastolic function in DCM rats. Immuno-electron microscopy and Western blot showed that CRT was present in cardiomyocyte mitochondria and the mitochondrial content of CRT was increased in DCM hearts (P<0.05). Morphometric analysis showed notable myocardial apoptosis and mitochondrial swelling with fractured or dissolved cristae in the DCM hearts. Compared with the control group, the mitochondrial membrane potential level of the freshly isolated cardiac mitochondria and the enzyme activities of cytochrome c oxidase and succinate dehydrogenase in the model group were significantly decreased (P<0.05), and the myocardial apoptosis index and the caspase activities of caspase-9 and caspase-3 were significantly increased (P<0.05). Pearson linear correlation analysis showed that the mitochondrial content of CRT had negative correlations with the mitochondrial function, and a positive correlation with myocardial apoptosis index (P<0.001). The protein expression level of cytochrome c and the phosphorylation activity of STAT3 in the mitochondrial fraction were significantly decreased in the model group compared with the control group (P<0.05). CONCLUSIONS These data demonstrate that CRT is localized at cardiomyocyte mitochondria and its mitochondrial content is increased in DCM hearts.
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Entamoeba histolytica and E. dispar Calreticulin: inhibition of classical complement pathway and differences in the level of expression in amoebic liver abscess. BIOMED RESEARCH INTERNATIONAL 2014; 2014:127453. [PMID: 24860808 PMCID: PMC4016843 DOI: 10.1155/2014/127453] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 02/19/2014] [Accepted: 03/07/2014] [Indexed: 12/26/2022]
Abstract
The role of calreticulin (CRT) in host-parasite interactions has recently become an important area of research. Information about the functions of calreticulin and its relevance to the physiology of Entamoeba parasites is limited. The present work demonstrates that CRT of both pathogenic E. histolytica and nonpathogenic E. dispar species specifically interacted with human C1q inhibiting the activation of the classical complement pathway. Using recombinant EhCRT protein, we demonstrate that CRT interaction site and human C1q is located at the N-terminal region of EhCRT. The immunofluorescence and confocal microscopy experiments show that CRT and human C1q colocalize in the cytoplasmic vesicles and near to the surface membrane of previously permeabilized trophozoites or are incubated with normal human serum which is known to destroy trophozoites. In the presence of peripheral mononuclear blood cells, the distribution of EhCRT and C1q is clearly over the surface membrane of trophozoites. Nevertheless, the level of expression of CRT in situ in lesions of amoebic liver abscess (ALA) in the hamster model is different in both Entamoeba species; this molecule is expressed in higher levels in E. histolytica than in E. dispar. This result suggests that EhCRT may modulate some functions during the early moments of the host-parasite relationship.
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Sateriale A, Roy NH, Huston CD. SNAP-tag technology optimized for use in Entamoeba histolytica. PLoS One 2013; 8:e83997. [PMID: 24391864 PMCID: PMC3877135 DOI: 10.1371/journal.pone.0083997] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 11/08/2013] [Indexed: 01/11/2023] Open
Abstract
Entamoeba histolytica is a protozoan parasite responsible for invasive intestinal and extraintestinal amebiasis. The pathology of amebiasis is still poorly understood, which can be largely attributed to lack of molecular tools. Here we present the optimization of SNAP-tag technology via codon optimization specific for E. histolytica. The resultant SNAP protein is highly expressed in amebic trophozoites, and shows proper localization when tagged with an endoplasmic reticulum retention signal. We further demonstrate the capabilities of this system using super resolution microscopy, done for the first time in E. histolytica.
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Affiliation(s)
- Adam Sateriale
- University of Vermont Cellular, Molecular, and Biomedical Sciences Program, Burlington, Vermont, United States of America
- University of Vermont Department of Medicine, Burlington, Vermont, United States of America
| | - Nathan H. Roy
- University of Vermont Cellular, Molecular, and Biomedical Sciences Program, Burlington, Vermont, United States of America
- University of Vermont Microbiology and Molecular Genetics, Burlington, Vermont, United States of America
| | - Christopher D. Huston
- University of Vermont Cellular, Molecular, and Biomedical Sciences Program, Burlington, Vermont, United States of America
- University of Vermont Microbiology and Molecular Genetics, Burlington, Vermont, United States of America
- University of Vermont Department of Medicine, Burlington, Vermont, United States of America
- * E-mail:
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Biller L, Matthiesen J, Kühne V, Lotter H, Handal G, Nozaki T, Saito-Nakano Y, Schümann M, Roeder T, Tannich E, Krause E, Bruchhaus I. The cell surface proteome of Entamoeba histolytica. Mol Cell Proteomics 2013; 13:132-44. [PMID: 24136294 PMCID: PMC3879609 DOI: 10.1074/mcp.m113.031393] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Surface molecules are of major importance for host-parasite interactions. During Entamoeba histolytica infections, these interactions are predicted to be of prime importance for tissue invasion, induction of colitis and liver abscess formation. To date, however, little is known about the molecules involved in these processes, with only about 20 proteins or protein families found exposed on the E. histolytica surface. We have therefore analyzed the complete surface proteome of E. histolytica. Using cell surface biotinylation and mass spectrometry, 693 putative surface-associated proteins were identified. In silico analysis predicted that ∼26% of these proteins are membrane-associated, as they contain transmembrane domains and/or signal sequences, as well as sites of palmitoylation, myristoylation, or prenylation. An additional 25% of the identified proteins likely represent nonclassical secreted proteins. Surprisingly, no membrane-association sites could be predicted for the remaining 49% of the identified proteins. To verify surface localization, 23 proteins were randomly selected and analyzed by immunofluorescence microscopy. Of these 23 proteins, 20 (87%) showed definite surface localization. These findings indicate that a far greater number of E. histolytica proteins than previously supposed are surface-associated, a phenomenon that may be based on the high membrane turnover of E. histolytica.
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Affiliation(s)
- Laura Biller
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359 Hamburg, Germany
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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: 1.3] [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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Abstract
The parasitic protozoan Entamoeba histolytica is aptly named for its capacity to destroy host tissue. When E. histolytica trophozoites invade the lamina propria of a host colon, extracellular matrices are degraded while host cells are killed and phagocytosed. The ability of E. histolytica to phagocytose host cells correlates with virulence in vivo. In order to better understand the mechanism of phagocytosis, we used an E. histolytica Affymetrix microarray chip to measure the total gene expression of phagocytic and nonphagocytic subpopulations. Using paramagnetic beads coated with a known host ligand that stimulates phagocytosis, phagocytic and nonphagocytic amoebae from a single culture were purified. Microarray analysis of the subpopulations identified 121 genes with >2-fold higher expression in phagocytic than in nonphagocytic amoebae. Functional annotation identified genes encoding proteins involved in actin binding and cytoskeletal organization as highly enriched gene clusters. Post hoc analyses of selected genes showed that the gene expression profile identified in the microarray experiment did not exist prior to cell sorting but rather was stimulated through phagocytosis. Further, these expression profiles correlated with an increase in phagocytic ability, as E. histolytica cultures exposed to an initial stimulus of phagocytosis showed increased phagocytic ability upon a second stimulus. To our knowledge, this is the first description of such feed-forward regulation of gene expression and phagocytic ability in a phagocyte.
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