1
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Audia S, Brescia C, Dattilo V, D’Antona L, Calvano P, Iuliano R, Trapasso F, Perrotti N, Amato R. RANBP1 (RAN Binding Protein 1): The Missing Genetic Piece in Cancer Pathophysiology and Other Complex Diseases. Cancers (Basel) 2023; 15:cancers15020486. [PMID: 36672435 PMCID: PMC9857238 DOI: 10.3390/cancers15020486] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/29/2022] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
RANBP1 encoded by RANBP1 or HTF9A (Hpall Tiny Fragments Locus 9A), plays regulatory functions of the RAN-network, belonging to the RAS superfamily of small GTPases. Through this function, RANBP1 regulates the RANGAP1 activity and, thus, the fluctuations between GTP-RAN and GDP-RAN. In the light of this, RANBP1 take actions in maintaining the nucleus-cytoplasmic gradient, thus making nuclear import-export functional. RANBP1 has been implicated in the inter-nuclear transport of proteins, nucleic acids and microRNAs, fully contributing to cellular epigenomic signature. Recently, a RANBP1 diriment role in spindle checkpoint formation and nucleation has emerged, thus constituting an essential element in the control of mitotic stability. Over time, RANBP1 has been demonstrated to be variously involved in human cancers both for the role in controlling nuclear transport and RAN activity and for its ability to determine the efficiency of the mitotic process. RANBP1 also appears to be implicated in chemo-hormone and radio-resistance. A key role of this small-GTPases related protein has also been demonstrated in alterations of axonal flow and neuronal plasticity, as well as in viral and bacterial metabolism and in embryological maturation. In conclusion, RANBP1 appears not only to be an interesting factor in several pathological conditions but also a putative target of clinical interest.
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Affiliation(s)
- Salvatore Audia
- Dipartimento di Scienze della Salute, Campus Salvatore Venuta, Università degli Studi “Magna Graecia” di Catanzaro, Viale Europa, 88100 Catanzaro, Italy
| | - Carolina Brescia
- Dipartimento di Scienze della Salute, Campus Salvatore Venuta, Università degli Studi “Magna Graecia” di Catanzaro, Viale Europa, 88100 Catanzaro, Italy
| | - Vincenzo Dattilo
- Dipartimento di Medicina Sperimentale e Clinica, Campus Salvatore Venuta, Università degli Studi “Magna Graecia” di Catanzaro, Viale Europa, 88100 Catanzaro, Italy
| | - Lucia D’Antona
- Dipartimento di Scienze della Salute, Campus Salvatore Venuta, Università degli Studi “Magna Graecia” di Catanzaro, Viale Europa, 88100 Catanzaro, Italy
| | - Pierluigi Calvano
- Dipartimento di Scienze della Salute, Campus Salvatore Venuta, Università degli Studi “Magna Graecia” di Catanzaro, Viale Europa, 88100 Catanzaro, Italy
| | - Rodolfo Iuliano
- Dipartimento di Scienze della Salute, Campus Salvatore Venuta, Università degli Studi “Magna Graecia” di Catanzaro, Viale Europa, 88100 Catanzaro, Italy
| | - Francesco Trapasso
- Dipartimento di Medicina Sperimentale e Clinica, Campus Salvatore Venuta, Università degli Studi “Magna Graecia” di Catanzaro, Viale Europa, 88100 Catanzaro, Italy
| | - Nicola Perrotti
- Dipartimento di Scienze della Salute, Campus Salvatore Venuta, Università degli Studi “Magna Graecia” di Catanzaro, Viale Europa, 88100 Catanzaro, Italy
| | - Rosario Amato
- Dipartimento di Scienze della Salute, Campus Salvatore Venuta, Università degli Studi “Magna Graecia” di Catanzaro, Viale Europa, 88100 Catanzaro, Italy
- Correspondence: ; Tel.: +39-0961-3694084
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2
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Lockwood DC, Amin H, Costa TRD, Schroeder GN. The Legionella pneumophila Dot/Icm type IV secretion system and its effectors. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35639581 DOI: 10.1099/mic.0.001187] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
To prevail in the interaction with eukaryotic hosts, many bacterial pathogens use protein secretion systems to release virulence factors at the host–pathogen interface and/or deliver them directly into host cells. An outstanding example of the complexity and sophistication of secretion systems and the diversity of their protein substrates, effectors, is the Defective in organelle trafficking/Intracellular multiplication (Dot/Icm) Type IVB secretion system (T4BSS) of
Legionella pneumophila
and related species.
Legionella
species are facultative intracellular pathogens of environmental protozoa and opportunistic human respiratory pathogens. The Dot/Icm T4BSS translocates an exceptionally large number of effectors, more than 300 per
L. pneumophila
strain, and is essential for evasion of phagolysosomal degradation and exploitation of protozoa and human macrophages as replicative niches. Recent technological advancements in the imaging of large protein complexes have provided new insight into the architecture of the T4BSS and allowed us to propose models for the transport mechanism. At the same time, significant progress has been made in assigning functions to about a third of
L. pneumophila
effectors, discovering unprecedented new enzymatic activities and concepts of host subversion. In this review, we describe the current knowledge of the workings of the Dot/Icm T4BSS machinery and provide an overview of the activities and functions of the to-date characterized effectors in the interaction of
L. pneumophila
with host cells.
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Affiliation(s)
- Daniel C Lockwood
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL, Northern Ireland, UK
| | - Himani Amin
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Tiago R D Costa
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Gunnar N Schroeder
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL, Northern Ireland, UK
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3
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Forbes G, Schilde C, Lawal H, Kin K, Du Q, Chen ZH, Rivero F, Schaap P. Interactome and evolutionary conservation of Dictyostelid small GTPases and their direct regulators. Small GTPases 2022; 13:239-254. [PMID: 34565293 PMCID: PMC8923023 DOI: 10.1080/21541248.2021.1984829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
GTP binding proteins known as small GTPases make up one of the largest groups of regulatory proteins and control almost all functions of living cells. Their activity is under, respectively, positive and negative regulation by guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs), which together with their upstream regulators and the downstream targets of the small GTPases form formidable signalling networks. While genomics has revealed the large size of the GTPase, GEF and GAP repertoires, only a small fraction of their interactions and functions have yet been experimentally explored. Dictyostelid social amoebas have been particularly useful in unravelling the roles of many proteins in the Rac-Rho and Ras-Rap families of GTPases in directional cell migration and regulation of the actin cytoskeleton. Genomes and cell-type specific and developmental transcriptomes are available for Dictyostelium species that span the 0.5 billion years of evolution of the group from their unicellular ancestors. In this work, we identified all GTPases, GEFs and GAPs from genomes representative of the four major taxon groups and investigated their phylogenetic relationships and evolutionary conservation and changes in their functional domain architecture and in their developmental and cell-type specific expression. We performed a hierarchical cluster analysis of the expression profiles of the ~2000 analysed genes to identify putative interacting sets of GTPases, GEFs and GAPs, which highlight sets known to interact experimentally and many novel combinations. This work represents a valuable resource for research into all fields of cellular regulation.
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Affiliation(s)
- Gillian Forbes
- School of Life Sciences, University of Dundee, Dundee, UK
| | | | - Hajara Lawal
- School of Life Sciences, University of Dundee, Dundee, UK
| | - Koryu Kin
- School of Life Sciences, University of Dundee, Dundee, UK,CSIC-Universitat Pompeu Fabra, Institut de Biologia Evolutiva (Csic-universitat Pompeu Fabra), Barcelona, Spain
| | - Qingyou Du
- School of Life Sciences, University of Dundee, Dundee, UK
| | - Zhi-hui Chen
- School of Life Sciences, University of Dundee, Dundee, UK
| | - Francisco Rivero
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, Faculty of Health Sciences, University of Hull, Hull, UK
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, Dundee, UK,CONTACT Pauline Schaap ; School of Life Sciences, University of Dundee, Msi/wtb Complex, Dundee, DD15EH, UK
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4
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Swart AL, Gomez-Valero L, Buchrieser C, Hilbi H. Evolution and function of bacterial RCC1 repeat effectors. Cell Microbiol 2020; 22:e13246. [PMID: 32720355 DOI: 10.1111/cmi.13246] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/10/2020] [Accepted: 07/11/2020] [Indexed: 01/02/2023]
Abstract
Intracellular bacterial pathogens harbour genes, the closest homologues of which are found in eukaryotes. Regulator of chromosome condensation 1 (RCC1) repeat proteins are phylogenetically widespread and implicated in protein-protein interactions, such as the activation of the small GTPase Ran by its cognate guanine nucleotide exchange factor, RCC1. Legionella pneumophila and Coxiella burnetii, the causative agents of Legionnaires' disease and Q fever, respectively, harbour RCC1 repeat coding genes. Legionella pneumophila secretes the RCC1 repeat 'effector' proteins LegG1, PpgA and PieG into eukaryotic host cells, where they promote the activation of the pleiotropic small GTPase Ran, microtubule stabilisation, pathogen vacuole motility and intracellular bacterial growth as well as host cell migration. The RCC1 repeat effectors localise to the pathogen vacuole or the host plasma membrane and target distinct components of the Ran GTPase cycle, including Ran modulators and the small GTPase itself. Coxiella burnetii translocates the RCC1 repeat effector NopA into host cells, where the protein localises to nucleoli. NopA binds to Ran GTPase and promotes the nuclear accumulation of Ran(GTP), thus pertubing the import of the transcription factor NF-κB and innate immune signalling. Hence, divergent evolution of bacterial RCC1 repeat effectors defines the range of Ran GTPase cycle targets and likely allows fine-tuning of Ran GTPase activation by the pathogens at different cellular sites.
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Affiliation(s)
- Anna Leoni Swart
- Institute of Medical Microbiology, Faculty of Medicine, University of Zurich, Zürich, Switzerland
| | - Laura Gomez-Valero
- Institut Pasteur, Unité de Biologie des Bactéries Intracellulaires, Paris, France.,CNRS UMR 3525, Paris, France
| | - Carmen Buchrieser
- Institut Pasteur, Unité de Biologie des Bactéries Intracellulaires, Paris, France.,CNRS UMR 3525, Paris, France
| | - Hubert Hilbi
- Institute of Medical Microbiology, Faculty of Medicine, University of Zurich, Zürich, Switzerland
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5
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Li P, Vassiliadis D, Ong SY, Bennett-Wood V, Sugimoto C, Yamagishi J, Hartland EL, Pasricha S. Legionella pneumophila Infection Rewires the Acanthamoeba castellanii Transcriptome, Highlighting a Class of Sirtuin Genes. Front Cell Infect Microbiol 2020; 10:428. [PMID: 32974218 PMCID: PMC7468528 DOI: 10.3389/fcimb.2020.00428] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 07/14/2020] [Indexed: 12/13/2022] Open
Abstract
Legionella pneumophila is an environmental bacterium that has evolved to survive predation by soil and water amoebae such as Acanthamoeba castellanii, and this has inadvertently led to the ability of L. pneumophila to survive and replicate in human cells. L. pneumophila causes Legionnaire's Disease, with human exposure occurring via the inhalation of water aerosols containing both amoebae and the bacteria. These aerosols originate from aquatic biofilms found in artifical water sources, such as air-conditioning cooling towers and humidifiers. In these man-made environments, A. castellanii supports L. pneumophila intracellular replication, thereby promoting persistence and dissemination of the bacteria and providing protection from external stress. Despite this close evolutionary relationship, very little is known about how A. castellanii responds to L. pneumophila infection. In this study, we examined the global transcriptional response of A. castellanii to L. pneumophila infection. We compared A. castellanii infected with wild type L. pneumophila to A. castellanii infected with an isogenic ΔdotA mutant strain, which is unable to replicate intracellularly. We showed that A. castellanii underwent clear morphological and transcriptional rewiring over the course of L. pneumophila infection. Through improved annotation of the A. castellanii genome, we determined that these transcriptional changes primarily involved biological processes utilizing small GTPases, including cellular transport, signaling, metabolism and replication. In addition, a number of sirtuin-encoding genes in A. castellanii were found to be conserved and upregulated during L. pneumophila infection. Silencing of sirtuin gene, sir6f (ACA1_153540) resulted in the inhibition of A. castellanii cell proliferation during infection and reduced L. pneumophila replication. Overall our findings identified several biological pathways in amoebae that may support L. pneumophila replication and A. castellanii proliferation in environmental conditions.
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Affiliation(s)
- Pengfei Li
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Dane Vassiliadis
- Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Sze Ying Ong
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Vicki Bennett-Wood
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Chihiro Sugimoto
- Global Station for Zoonosis Control, GI-CoRE, Hokkaido University, Sapporo, Japan.,Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Junya Yamagishi
- Global Station for Zoonosis Control, GI-CoRE, Hokkaido University, Sapporo, Japan.,Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Elizabeth L Hartland
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia.,Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan.,Department of Molecular and Translational Science, Monash University, Clayton, VIC, Australia
| | - Shivani Pasricha
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
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6
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A MicroRNA Network Controls Legionella pneumophila Replication in Human Macrophages via LGALS8 and MX1. mBio 2020; 11:mBio.03155-19. [PMID: 32209695 PMCID: PMC7157531 DOI: 10.1128/mbio.03155-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cases of Legionella pneumophila pneumonia occur worldwide, with potentially fatal outcome. When causing human disease, Legionella injects a plethora of virulence factors to reprogram macrophages to circumvent immune defense and create a replication niche. By analyzing Legionella-induced changes in miRNA expression and genomewide chromatin modifications in primary human macrophages, we identified a cell-autonomous immune network restricting Legionella growth. This network comprises three miRNAs governing expression of the cytosolic RNA receptor DDX58/RIG-I, the tumor suppressor TP53, the antibacterial effector LGALS8, and MX1, which has been described as an antiviral factor. Our findings for the first time link TP53, LGALS8, DDX58, and MX1 in one miRNA-regulated network and integrate them into a functional node in the defense against L. pneumophila. Legionella pneumophila is an important cause of pneumonia. It invades alveolar macrophages and manipulates the immune response by interfering with signaling pathways and gene transcription to support its own replication. MicroRNAs (miRNAs) are critical posttranscriptional regulators of gene expression and are involved in defense against bacterial infections. Several pathogens have been shown to exploit the host miRNA machinery to their advantage. We therefore hypothesize that macrophage miRNAs exert positive or negative control over Legionella intracellular replication. We found significant regulation of 85 miRNAs in human macrophages upon L. pneumophila infection. Chromatin immunoprecipitation and sequencing revealed concordant changes of histone acetylation at the putative promoters. Interestingly, a trio of miRNAs (miR-125b, miR-221, and miR-579) was found to significantly affect intracellular L. pneumophila replication in a cooperative manner. Using proteome-analysis, we pinpointed this effect to a concerted downregulation of galectin-8 (LGALS8), DExD/H-box helicase 58 (DDX58), tumor protein P53 (TP53), and then MX dynamin-like GTPase 1 (MX1) by the three miRNAs. In summary, our results demonstrate a new miRNA-controlled immune network restricting Legionella replication in human macrophages.
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7
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Hochstrasser R, Hutter CAJ, Arnold FM, Bärlocher K, Seeger MA, Hilbi H. The structure of the
Legionella
response regulator LqsR reveals amino acids critical for phosphorylation and dimerization. Mol Microbiol 2020; 113:1070-1084. [DOI: 10.1111/mmi.14477] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 12/16/2022]
Affiliation(s)
- Ramon Hochstrasser
- Institute of Medical Microbiology University of Zürich Zürich Switzerland
| | | | - Fabian M. Arnold
- Institute of Medical Microbiology University of Zürich Zürich Switzerland
| | - Kevin Bärlocher
- Institute of Medical Microbiology University of Zürich Zürich Switzerland
| | - Markus A. Seeger
- Institute of Medical Microbiology University of Zürich Zürich Switzerland
| | - Hubert Hilbi
- Institute of Medical Microbiology University of Zürich Zürich Switzerland
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8
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Coppola U, Caccavale F, Scelzo M, Holland ND, Ristoratore F, D’Aniello S. Ran GTPase, an eukaryotic gene novelty, is involved in amphioxus mitosis. PLoS One 2018; 13:e0196930. [PMID: 30300344 PMCID: PMC6177115 DOI: 10.1371/journal.pone.0196930] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 04/23/2018] [Indexed: 01/19/2023] Open
Abstract
Ran (ras-related nuclear protein) is a small GTPase belonging to the RAS superfamily that is specialized in nuclear trafficking. Through different accessory proteins, Ran plays key roles in several processes including nuclear import-export, mitotic progression and spindle assembly. Consequently, Ran dysfunction has been linked to several human pathologies. This work illustrates the high degree of amino acid conservation of Ran orthologues across evolution, reflected in its conserved role in nuclear trafficking. Moreover, we studied the evolutionary scenario of the pre-metazoan genetic linkage between Ran and Stx, and we hypothesized that chromosomal proximity of these two genes across metazoans could be related to a regulatory logic or a functional linkage. We studied, for the first time, Ran expression during amphioxus development and reported its presence in the neural vesicle, mouth, gill slits and gut corresponding to body regions involved in active cell division.
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Affiliation(s)
- Ugo Coppola
- Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, Villa Comunale, Napoli, Italy
| | - Filomena Caccavale
- Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, Villa Comunale, Napoli, Italy
| | - Marta Scelzo
- Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, Villa Comunale, Napoli, Italy
- Laboratory of Developmental Biology of Villefranche sur Mer, UMR7009 CNRS/UPMC Observatoire Océanologique, Villefranche sur Mer, France
| | - Nicholas D. Holland
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA, United States of America
| | - Filomena Ristoratore
- Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, Villa Comunale, Napoli, Italy
| | - Salvatore D’Aniello
- Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, Villa Comunale, Napoli, Italy
- * E-mail:
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9
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Sun S, Noorian P, McDougald D. Dual Role of Mechanisms Involved in Resistance to Predation by Protozoa and Virulence to Humans. Front Microbiol 2018; 9:1017. [PMID: 29867902 PMCID: PMC5967200 DOI: 10.3389/fmicb.2018.01017] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 04/30/2018] [Indexed: 12/12/2022] Open
Abstract
Most opportunistic pathogens transit in the environment between hosts and the environment plays a significant role in the evolution of protective traits. The coincidental evolution hypothesis suggests that virulence factors arose as a response to other selective pressures rather for virulence per se. This idea is strongly supported by the elucidation of bacterial-protozoal interactions. In response to protozoan predation, bacteria have evolved various defensive mechanisms which may also function as virulence factors. In this review, we summarize the dual role of factors involved in both grazing resistance and human pathogenesis, and compare the traits using model intracellular and extracellular pathogens. Intracellular pathogens rely on active invasion, blocking of the phagosome and lysosome fusion and resistance to phagocytic digestion to successfully invade host cells. In contrast, extracellular pathogens utilize toxin secretion and biofilm formation to avoid internalization by phagocytes. The complexity and diversity of bacterial virulence factors whose evolution is driven by protozoan predation, highlights the importance of protozoa in evolution of opportunistic pathogens.
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Affiliation(s)
- Shuyang Sun
- ithree Institute, University of Technology Sydney, Sydney, NSW, Australia
| | - Parisa Noorian
- ithree Institute, University of Technology Sydney, Sydney, NSW, Australia.,School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Diane McDougald
- ithree Institute, University of Technology Sydney, Sydney, NSW, Australia.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
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10
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Guimaraes AJ, Gomes KX, Cortines JR, Peralta JM, Peralta RHS. Acanthamoeba spp. as a universal host for pathogenic microorganisms: One bridge from environment to host virulence. Microbiol Res 2016; 193:30-38. [PMID: 27825484 DOI: 10.1016/j.micres.2016.08.001] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 06/02/2016] [Accepted: 08/01/2016] [Indexed: 10/21/2022]
Abstract
Free-living amoebas (FLA) are ubiquitous environmental protists that have enormously contributed to the microbiological contamination of water sources. FLAs have displayed resistance to environmental adversities and germicides and have played important roles in the population control of microbial communities due to its predatory behavior and microbicidal activity. However, some organisms have developed resistance to the intracellular milieu of amoebas, as in the case of Acanthamoebas, which in turn, have been functioning as excellent reservoirs for amoeba-resistant microorganisms (ARMs), such as bacteria, viruses and fungi. Little is known about these relationships and interaction mechanisms, but it is speculated that the FLAs need a very broad repertoire or universal class of receptors to bind and recognize these diverse species of microorganisms. By harboring these organisms as a "Trojan Horse", the Achantamoeba has been working as an excellent vector for pathogens. Moreover, studies have demonstrated that the interaction of pathogens with Acanthamoeba results in environmental selective pressure responsible for induction and maintenance of virulence factors and increase in microbial pathogenicity. This phenomenon is correlated to the observation of higher gene number and DNA content of ARMs, when compared to their relatives which are adapted to other hosts, due to allopatric or sympatric gene transfer and acquisition, contradicting the overall genome reduction theory for intracellularly adapted pathogens. Thus, adaptation to FLAs indirectly provided a "learning" environment for pathogens to resist later to macrophages; besides the evolutionary distance, these phagocytes share similar predatory mechanisms, such as phagocytosis and phagolysossomal degradation. In this mini-review, we cover the most important aspects of Acanthamoeba biology and their interactions with endemically important human pathogens.
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Affiliation(s)
- Allan J Guimaraes
- Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Brazil.
| | - Kamilla Xavier Gomes
- Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Brazil
| | - Juliana Reis Cortines
- Departamento de Virologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Brazil
| | - José Mauro Peralta
- Departamento de Imunologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Brazil.
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11
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Finsel I, Hilbi H. Formation of a pathogen vacuole according to Legionella pneumophila: how to kill one bird with many stones. Cell Microbiol 2015; 17:935-50. [PMID: 25903720 DOI: 10.1111/cmi.12450] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/13/2015] [Accepted: 04/17/2015] [Indexed: 12/12/2022]
Abstract
Legionella species are ubiquitous, waterborne bacteria that thrive in numerous ecological niches. Yet, in contrast to many other environmental bacteria, Legionella spp. are also able to grow intracellularly in predatory protozoa. This feature mainly accounts for the pathogenicity of Legionella pneumophila, which causes the majority of clinical cases of a severe pneumonia termed Legionnaires' disease. The pathomechanism underlying L. pneumophila infection is based on macrophage resistance, which in turn is largely defined by the opportunistic pathogen's resistance towards amoebae. L. pneumophila replicates in macrophages or amoebae in a unique membrane-bound compartment, the Legionella-containing vacuole (LCV). LCV formation requires the bacterial intracellular multiplication/defective for organelle trafficking (Icm/Dot) type IV secretion system and involves a plethora of translocated effector proteins, which subvert pivotal processes in the host cell. Of the ca. 300 different experimentally validated Icm/Dot substrates, about 50 have been studied and attributed a cellular function to date. The versatility and ingenuity of these effectors' mode of actions is striking. In this review, we summarize insight into the cellular functions and biochemical activities of well-characterized L. pneumophila effector proteins and the host pathways they target. Recent studies not only substantially increased our knowledge about pathogen-host interactions, but also shed light on novel biological mechanisms.
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Affiliation(s)
- Ivo Finsel
- Max von Pettenkofer Institute, Ludwig-Maximilians University, Munich, Germany
| | - Hubert Hilbi
- Max von Pettenkofer Institute, Ludwig-Maximilians University, Munich, Germany.,Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
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12
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Weber S, Stirnimann CU, Wieser M, Frey D, Meier R, Engelhardt S, Li X, Capitani G, Kammerer RA, Hilbi H. A type IV translocated Legionella cysteine phytase counteracts intracellular growth restriction by phytate. J Biol Chem 2014; 289:34175-88. [PMID: 25339170 DOI: 10.1074/jbc.m114.592568] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The causative agent of Legionnaires' pneumonia, Legionella pneumophila, colonizes diverse environmental niches, including biofilms, plant material, and protozoa. In these habitats, myo-inositol hexakisphosphate (phytate) is prevalent and used as a phosphate storage compound or as a siderophore. L. pneumophila replicates in protozoa and mammalian phagocytes within a unique "Legionella-containing vacuole." The bacteria govern host cell interactions through the Icm/Dot type IV secretion system (T4SS) and ∼300 different "effector" proteins. Here we characterize a hitherto unrecognized Icm/Dot substrate, LppA, as a phytate phosphatase (phytase). Phytase activity of recombinant LppA required catalytically essential cysteine (Cys(231)) and arginine (Arg(237)) residues. The structure of LppA at 1.4 Å resolution revealed a mainly α-helical globular protein stabilized by four antiparallel β-sheets that binds two phosphate moieties. The phosphates localize to a P-loop active site characteristic of dual specificity phosphatases or to a non-catalytic site, respectively. Phytate reversibly abolished growth of L. pneumophila in broth, and growth inhibition was relieved by overproduction of LppA or by metal ion titration. L. pneumophila lacking lppA replicated less efficiently in phytate-loaded Acanthamoeba castellanii or Dictyostelium discoideum, and the intracellular growth defect was complemented by the phytase gene. These findings identify the chelator phytate as an intracellular bacteriostatic component of cell-autonomous host immunity and reveal a T4SS-translocated L. pneumophila phytase that counteracts intracellular bacterial growth restriction by phytate. Thus, bacterial phytases might represent therapeutic targets to combat intracellular pathogens.
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Affiliation(s)
- Stephen Weber
- From the Max von Pettenkofer Institute, Department of Medicine, Ludwig-Maximilians University Munich, 80336 Munich, Germany
| | - Christian U Stirnimann
- the Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Mara Wieser
- the Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Daniel Frey
- the Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Roger Meier
- the Scientific Center for Optical and Electron Microscopy, ETH Zurich, 8093 Zurich, Switzerland
| | - Sabrina Engelhardt
- the Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology (ZIHP), Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland, and
| | - Xiaodan Li
- the Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Guido Capitani
- the Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Richard A Kammerer
- the Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Hubert Hilbi
- From the Max von Pettenkofer Institute, Department of Medicine, Ludwig-Maximilians University Munich, 80336 Munich, Germany, the Institute of Medical Microbiology, Department of Medicine, University of Zurich, 8006 Zurich, Switzerland
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