1
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Hamilton WC, Newton ILG. crANKing up the infection: ankyrin domains in Rickettsiales and their role in host manipulation. Infect Immun 2024:e0005924. [PMID: 39212405 DOI: 10.1128/iai.00059-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024] Open
Abstract
Intracellular bacteria use secreted effector proteins to modify host biology and facilitate infection. For many of these microbes, a particular eukaryotic domain-the ankyrin repeat (ANK)-plays a central role in specifying the host proteins and pathways targeted by the microbe. While we understand much of how some ANKs function in model organisms like Legionella and Coxiella, the understudied Rickettsiales species harbor many proteins with ANKs, some of which play critical roles during infection. This minireview is meant to organize and summarize the research progress made in understanding some of these Rickettsiales ANKs as well as document some of the techniques that have driven much of this progress.
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Affiliation(s)
| | - Irene L G Newton
- Department of Biology, Indiana University, Bloomington, Indiana, USA
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2
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Wang L, Lin M, Hou L, Rikihisa Y. Anaplasma phagocytophilum effector EgeA facilitates infection by hijacking TANGO1 and SCFD1 from ER-Golgi exit sites to pathogen-occupied inclusions. Proc Natl Acad Sci U S A 2024; 121:e2405209121. [PMID: 39106308 PMCID: PMC11331065 DOI: 10.1073/pnas.2405209121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 07/01/2024] [Indexed: 08/09/2024] Open
Abstract
The obligatory intracellular bacterium Anaplasma phagocytophilum causes human granulocytic anaplasmosis, an emerging zoonosis. Anaplasma has limited biosynthetic and metabolic capacities, yet it effectively replicates inside of inclusions/vacuoles of eukaryotic host cells. Here, we describe a unique Type IV secretion system (T4SS) effector, ER-Golgi exit site protein of Anaplasma (EgeA). In cells infected by Anaplasma, secreted native EgeA, EgeA-GFP, and the C-terminal half of EgeA (EgeA-C)-GFP localized to Anaplasma-containing inclusions. In uninfected cells, EgeA-C-GFP localized to cis-Golgi, whereas the N-terminal half of EgeA-GFP localized to the ER. Pull-down assays identified EgeA-GFP binding to a transmembrane protein in the ER, Transport and Golgi organization protein 1 (TANGO1). By yeast two-hybrid analysis, EgeA-C directly bound Sec1 family domain-containing protein 1 (SCFD1), a host protein of the cis-Golgi network that binds TANGO1 at ER-Golgi exit sites (ERES). Both TANGO1 and SCFD1 localized to the Anaplasma inclusion surface. Furthermore, knockdown of Anaplasma EgeA or either host TANGO1 or SCFD1 significantly reduced Anaplasma infection. TANGO1 and SCFD1 prevent ER congestion and stress by facilitating transport of bulky or unfolded proteins at ERES. A bulky cargo collagen and the ER-resident chaperon BiP were transported into Anaplasma inclusions, and several ER stress marker genes were not up-regulated in Anaplasma-infected cells. Furthermore, EgeA transfection reduced collagen overexpression-induced BiP upregulation. These results suggest that by binding to the two ERES proteins, EgeA redirects the cargo-adapted ERES to pathogen-occupied inclusions and reduces ERES congestion, which facilitates Anaplasma nutrient acquisition and reduces ER stress for Anaplasma survival and proliferation.
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Affiliation(s)
- Lidan Wang
- Department of Veterinary Biosciences, College of Veterinary Medicine, Infectious Diseases Institute, The Ohio State University, Columbus, OH43210
| | - Mingqun Lin
- Department of Veterinary Biosciences, College of Veterinary Medicine, Infectious Diseases Institute, The Ohio State University, Columbus, OH43210
| | - Libo Hou
- Department of Veterinary Biosciences, College of Veterinary Medicine, Infectious Diseases Institute, The Ohio State University, Columbus, OH43210
| | - Yasuko Rikihisa
- Department of Veterinary Biosciences, College of Veterinary Medicine, Infectious Diseases Institute, The Ohio State University, Columbus, OH43210
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3
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Lehman SS, Verhoeve VI, Driscoll TP, Beckmann JF, Gillespie JJ. Metagenome diversity illuminates the origins of pathogen effectors. mBio 2024; 15:e0075923. [PMID: 38564675 PMCID: PMC11077975 DOI: 10.1128/mbio.00759-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 02/12/2024] [Indexed: 04/04/2024] Open
Abstract
Recent metagenome-assembled genome (MAG) analyses have profoundly impacted Rickettsiology systematics. The discovery of basal lineages (novel families Mitibacteraceae and Athabascaceae) with predicted extracellular lifestyles exposed an evolutionary timepoint for the transition to host dependency, which seemingly occurred independent of mitochondrial evolution. Notably, these basal rickettsiae carry the Rickettsiales vir homolog (rvh) type IV secretion system and purportedly use rvh to kill congener microbes rather than parasitize host cells as described for later-evolving rickettsial pathogens. MAG analysis also substantially increased diversity for the genus Rickettsia and delineated a sister lineage (the novel genus Tisiphia) that stands to inform on the emergence of human pathogens from protist and invertebrate endosymbionts. Herein, we probed Rickettsiales MAG and genomic diversity for the distribution of Rickettsia rvh effectors to ascertain their origins. A sparse distribution of most Rickettsia rvh effectors outside of Rickettsiaceae lineages illuminates unique rvh evolution from basal extracellular species and other rickettsial families. Remarkably, nearly every effector was found in multiple divergent forms with variable architectures, indicating profound roles for gene duplication and recombination in shaping effector repertoires in Rickettsia pathogens. Lateral gene transfer plays a prominent role in shaping the rvh effector landscape, as evinced by the discovery of many effectors on plasmids and conjugative transposons, as well as pervasive effector gene exchange between Rickettsia and Legionella species. Our study exemplifies how MAGs can yield insight into pathogen effector origins, particularly how effector architectures might become tailored to the discrete host cell functions of different eukaryotic hosts.IMPORTANCEWhile rickettsioses are deadly vector-borne human diseases, factors distinguishing Rickettsia pathogens from the innumerable bevy of environmental rickettsial endosymbionts remain lacking. Recent metagenome-assembled genome (MAG) studies revealed evolutionary timepoints for rickettsial transitions to host dependency. The rvh type IV secretion system was likely repurposed from congener killing in basal extracellular species to parasitizing host cells in later-evolving pathogens. Our analysis of MAG diversity for over two dozen rvh effectors unearthed their presence in some non-pathogens. However, most effectors were found in multiple divergent forms with variable architectures, indicating gene duplication and recombination-fashioned effector repertoires of Rickettsia pathogens. Lateral gene transfer substantially shaped pathogen effector arsenals, evinced by the discovery of effectors on plasmids and conjugative transposons, as well as pervasive effector gene exchanges between Rickettsia and Legionella species. Our study exemplifies how MAGs yield insight into pathogen effector origins and evolutionary processes tailoring effectors to eukaryotic host cell biology.
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Affiliation(s)
- Stephanie S. Lehman
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Victoria I. Verhoeve
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Timothy P. Driscoll
- Department of Biology, West Virginia University, Morgantown, West Virginia, USA
| | - John F. Beckmann
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama, USA
| | - Joseph J. Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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4
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Rasouli M, Safari F, Sobhani N, Alavi M, Roudi R. Regulation of Cellular-Signaling Pathways by Mammalian Proteins Containing Bacterial EPIYA or EPIYA-Like Motifs Predicted to be Phosphorylated. DNA Cell Biol 2024; 43:74-84. [PMID: 38153368 DOI: 10.1089/dna.2023.0350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023] Open
Abstract
The effector proteins of several pathogenic bacteria contain the Glu-Pro-Ile-Tyr-Ala (EPIYA) motif or other similar motifs. The EPIYA motif is delivered into the host cells by type III and IV secretion systems, through which its tyrosine residue undergoes phosphorylation by host kinases. These motifs atypically interact with a wide range of Src homology 2 (SH2) domain-containing mammalian proteins through tyrosine phosphorylation, which leads to the perturbation of multiple signaling cascades, the spread of infection, and improved bacterial colonization. Interestingly, it has been reported that EPIYA (or EPIYA-like) motifs exist in mammalian proteomes and regulate mammalian cellular-signaling pathways, leading to homeostasis and disease pathophysiology. It is possible that pathogenic bacteria have exploited EPIYA (or EPIYA-like) motifs from mammalian proteins and that the mammalian EPIYA (or EPIYA-like) motifs have evolved to have highly specific interactions with SH2 domain-containing proteins. In this review, we focus on the regulation of mammalian cellular-signaling pathways by mammalian proteins containing these motifs.
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Affiliation(s)
- Mohammad Rasouli
- Department of Biology, Faculty of Science, University of Guilan, Rasht, Iran
| | - Fatemeh Safari
- Department of Biology, Faculty of Science, University of Guilan, Rasht, Iran
| | - Navid Sobhani
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Mana Alavi
- Department of Biology, Faculty of Science, University of Guilan, Rasht, Iran
| | - Raheleh Roudi
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, Stanford University, Stanford, California, USA
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5
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Giengkam S, Kullapanich C, Wongsantichon J, Adcox HE, Gillespie JJ, Salje J. Orientia tsutsugamushi: comprehensive analysis of the mobilome of a highly fragmented and repetitive genome reveals the capacity for ongoing lateral gene transfer in an obligate intracellular bacterium. mSphere 2023; 8:e0026823. [PMID: 37850800 PMCID: PMC10732058 DOI: 10.1128/msphere.00268-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/22/2023] [Indexed: 10/19/2023] Open
Abstract
IMPORTANCE Obligate intracellular bacteria, or those only capable of growth inside other living cells, have limited opportunities for horizontal gene transfer with other microbes due to their isolated replicative niche. The human pathogen Ot, an obligate intracellular bacterium causing scrub typhus, encodes an unusually high copy number of a ~40 gene mobile genetic element that typically facilitates genetic transfer across microbes. This proliferated element is heavily degraded in Ot and previously assumed to be inactive. Here, we conducted a detailed analysis of this element in eight Ot strains and discovered two strains with at least one intact copy. This implies that the element is still capable of moving across Ot populations and suggests that the genome of this bacterium may be even more dynamic than previously appreciated. Our work raises questions about intracellular microbial evolution and sounds an alarm for gene-based efforts focused on diagnosing and combatting scrub typhus.
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Affiliation(s)
- Suparat Giengkam
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chitrasak Kullapanich
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jantana Wongsantichon
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Haley E. Adcox
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, USA
| | - Joseph J. Gillespie
- Department of Microbiology and Immunology, School of Medicine, University of Maryland Baltimore, Baltimore, Maryland, USA
| | - Jeanne Salje
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
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6
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Chien RC, Mingqun L, Yan Q, Randolph N, Huang W, Wellman M, Toribio R, Rikihisa Y. Strains of Anaplasma phagocytophilum from horses in Ohio are related to isolates from humans in the northeastern USA. Microbiol Spectr 2023; 11:e0263223. [PMID: 37882777 PMCID: PMC10715102 DOI: 10.1128/spectrum.02632-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/15/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE The tick-borne obligatory intracellular bacterium Anaplasma phagocytophilum infects humans as well as domesticated and wild animals, causing a febrile disease collectively called granulocytic anaplasmosis. The epidemiology and the host species specificity and zoonotic potential of A. phagocytophilum strains remain unclear. In this study, ankA (encoding ankyrin A) and p44 gene sequences of A. phagocytophilum were determined in clinical specimens from horses in Ohio and compared with those found in A. phagocytophilum strains from various hosts and geographic regions. With increasing numbers of seropositive horses, the study points out the unrecognized prevalence and uncharacterized strains of A. phagocytophilum infection in horses and the importance of A. phagocytophilum molecular testing for the prevention of equine and human granulocytic anaplasmosis.
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Affiliation(s)
- Rory C Chien
- Laboratory of Molecular, Cellular, and Environmental Rickettsiology, Infectious Diseases Institute, The Ohio State University , Columbus, Ohio, USA
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio, USA
| | - Lin Mingqun
- Laboratory of Molecular, Cellular, and Environmental Rickettsiology, Infectious Diseases Institute, The Ohio State University , Columbus, Ohio, USA
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio, USA
| | - Qi Yan
- Laboratory of Molecular, Cellular, and Environmental Rickettsiology, Infectious Diseases Institute, The Ohio State University , Columbus, Ohio, USA
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio, USA
| | - Nina Randolph
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio, USA
| | - Weiyan Huang
- Laboratory of Molecular, Cellular, and Environmental Rickettsiology, Infectious Diseases Institute, The Ohio State University , Columbus, Ohio, USA
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio, USA
| | - Maxey Wellman
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio, USA
| | - Ramiro Toribio
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio, USA
| | - Yasuko Rikihisa
- Laboratory of Molecular, Cellular, and Environmental Rickettsiology, Infectious Diseases Institute, The Ohio State University , Columbus, Ohio, USA
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio, USA
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7
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Park JM, Genera BM, Fahy D, Swallow KT, Nelson CM, Oliver JD, Shaw DK, Munderloh UG, Brayton KA. An Anaplasma phagocytophilum T4SS effector, AteA, is essential for tick infection. mBio 2023; 14:e0171123. [PMID: 37747883 PMCID: PMC10653876 DOI: 10.1128/mbio.01711-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Accepted: 07/26/2023] [Indexed: 09/27/2023] Open
Abstract
IMPORTANCE Ticks are the number one vector of pathogens for livestock worldwide and for humans in the United States. The biology of tick transmission is an understudied area. Understanding this critical interaction could provide opportunities to affect the course of disease spread. In this study, we examined the zoonotic tick-borne agent Anaplasma phagocytophilum and identified a secreted protein, AteA, which is expressed in a tick-specific manner. These secreted proteins, termed effectors, are the first proteins to interact with the host environment. AteA is essential for survival in ticks and appears to interact with cortical actin. Most effector proteins are studied in the context of the mammalian host; however, understanding how this unique set of proteins affects tick transmission is critical to developing interventions.
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Affiliation(s)
- Jason M. Park
- Program in Vector-borne Disease, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Brittany M. Genera
- Program in Vector-borne Disease, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Deirdre Fahy
- Program in Vector-borne Disease, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Kyle T. Swallow
- Program in Vector-borne Disease, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Curtis M. Nelson
- Department of Entomology, College of Food, Agricultural, and Natural Resource Sciences, University of Minnesota, Saint Paul, Minnesota, USA
| | - Jonathan D. Oliver
- Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, Minnesota, USA
| | - Dana K. Shaw
- Program in Vector-borne Disease, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Ulrike G. Munderloh
- Department of Entomology, College of Food, Agricultural, and Natural Resource Sciences, University of Minnesota, Saint Paul, Minnesota, USA
| | - Kelly A. Brayton
- Program in Vector-borne Disease, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
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8
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Giengkam S, Kullapanich C, Wongsantichon J, Adcox HE, Gillespie JJ, Salje J. Orientia tsutsugamushi: analysis of the mobilome of a highly fragmented and repetitive genome reveals ongoing lateral gene transfer in an obligate intracellular bacterium. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.11.540415. [PMID: 37215039 PMCID: PMC10197636 DOI: 10.1101/2023.05.11.540415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The rickettsial human pathogen Orientia tsutsugamushi (Ot) is an obligate intracellular Gram-negative bacterium with one of the most highly fragmented and repetitive genomes of any organism. Around 50% of its ~2.3 Mb genome is comprised of repetitive DNA that is derived from the highly proliferated Rickettsiales amplified genetic element (RAGE). RAGE is an integrative and conjugative element (ICE) that is present in a single Ot genome in up to 92 copies, most of which are partially or heavily degraded. In this report, we analysed RAGEs in eight fully sequenced Ot genomes and manually curated and reannotated all RAGE-associated genes, including those encoding DNA mobilisation proteins, P-type (vir) and F-type (tra) type IV secretion system (T4SS) components, Ankyrin repeat- and tetratricopeptide repeat-containing effectors, and other piggybacking cargo. Originally, the heavily degraded Ot RAGEs led to speculation that they are remnants of historical ICEs that are no longer active. Our analysis, however, identified two Ot genomes harbouring one or more intact RAGEs with complete F-T4SS genes essential for mediating ICE DNA transfer. As similar ICEs have been identified in unrelated rickettsial species, we assert that RAGEs play an ongoing role in lateral gene transfer within the Rickettsiales. Remarkably, we also identified in several Ot genomes remnants of prophages with no similarity to other rickettsial prophages. Together these findings indicate that, despite their obligate intracellular lifestyle and host range restricted to mites, rodents and humans, Ot genomes are highly dynamic and shaped through ongoing invasions by mobile genetic elements and viruses.
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Affiliation(s)
- Suparat Giengkam
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chitrasak Kullapanich
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jantana Wongsantichon
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Haley E. Adcox
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, USA
| | - Joseph J. Gillespie
- Department of Microbiology and Immunology, School of Medicine, University of Maryland Baltimore, MD 21201
| | - Jeanne Salje
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Pathology, Department of Biochemistry, Cambridge Institute for Medical Research, University of Cambridge, UK
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9
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Londoño AF, Scorpio DG, Dumler JS. Innate immunity in rickettsial infections. Front Cell Infect Microbiol 2023; 13:1187267. [PMID: 37228668 PMCID: PMC10203653 DOI: 10.3389/fcimb.2023.1187267] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 04/19/2023] [Indexed: 05/27/2023] Open
Abstract
Rickettsial agents are a diverse group of alpha-proteobacteria within the order Rickettsiales, which possesses two families with human pathogens, Rickettsiaceae and Anaplasmataceae. These obligate intracellular bacteria are most frequently transmitted by arthropod vectors, a first step in the pathogens' avoidance of host cell defenses. Considerable study of the immune responses to infection and those that result in protective immunity have been conducted. Less study has focused on the initial events and mechanism by which these bacteria avoid the innate immune responses of the hosts to survive within and propagate from host cells. By evaluating the major mechanisms of evading innate immunity, a range of similarities among these bacteria become apparent, including mechanisms to escape initial destruction in phagolysosomes of professional phagocytes, those that dampen the responses of innate immune cells or subvert signaling and recognition pathways related to apoptosis, autophagy, proinflammatory responses, and mechanisms by which these microbes attach to and enter cells or those molecules that trigger the host responses. To illustrate these principles, this review will focus on two common rickettsial agents that occur globally, Rickettsia species and Anaplasma phagocytophilum.
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Affiliation(s)
- Andrés F. Londoño
- The Henry M. Jackson Foundation for Advancement in Military Medicine, Bethesda, MD, United States
- Department of Pathology, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Diana G. Scorpio
- Host-Pathogen Interactions Program, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - J. Stephen Dumler
- Department of Pathology, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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10
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Verhoeve VI, Lehman SS, Driscoll TP, Beckmann JF, Gillespie JJ. Metagenome diversity illuminates origins of pathogen effectors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.26.530123. [PMID: 36909625 PMCID: PMC10002696 DOI: 10.1101/2023.02.26.530123] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Recent metagenome assembled genome (MAG) analyses have profoundly impacted Rickettsiology systematics. Discovery of basal lineages (Mitibacteraceae and Athabascaceae) with predicted extracellular lifestyles reveals an evolutionary timepoint for the transition to host dependency, which occurred independent of mitochondrial evolution. Notably, these basal rickettsiae carry the Rickettsiales vir homolog (rvh) type IV secretion system (T4SS) and purportedly use rvh to kill congener microbes rather than parasitize host cells as described for derived rickettsial pathogens. MAG analysis also substantially increased diversity for genus Rickettsia and delineated a basal lineage (Tisiphia) that stands to inform on the rise of human pathogens from protist and invertebrate endosymbionts. Herein, we probed Rickettsiales MAG and genomic diversity for the distribution of Rickettsia rvh effectors to ascertain their origins. A sparse distribution of most Rickettsia rvh effectors outside of Rickettsiaceae lineages indicates unique rvh evolution from basal extracellular species and other rickettsial families. Remarkably, nearly every effector was found in multiple divergent forms with variable architectures, illuminating profound roles for gene duplication and recombination in shaping effector repertoires in Rickettsia pathogens. Lateral gene transfer plays a prominent role shaping the rvh effector landscape, as evinced by the discover of many effectors on plasmids and conjugative transposons, as well as pervasive effector gene exchange between Rickettsia and Legionella species. Our study exemplifies how MAGs can provide incredible insight on the origins of pathogen effectors and how their architectural modifications become tailored to eukaryotic host cell biology.
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Affiliation(s)
- Victoria I Verhoeve
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Stephanie S Lehman
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Timothy P Driscoll
- Department of Biology, West Virginia University, Morgantown, West Virginia, USA
| | - John F Beckmann
- Microbiology and Immunology, University of South Alabama, Mobile, AL, USA
| | - Joseph J Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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11
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Park JM, Genera BM, Fahy D, Swallow KT, Nelson CM, Oliver JD, Shaw DK, Munderloh UG, Brayton KA. An Anaplasma phagocytophilum T4SS effector, AteA, is essential for tick infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.06.527355. [PMID: 36798287 PMCID: PMC9934581 DOI: 10.1101/2023.02.06.527355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Pathogens must adapt to disparate environments in permissive host species, a feat that is especially pronounced for vector-borne microbes, which transition between vertebrate hosts and arthropod vectors to complete their lifecycles. Most knowledge about arthropod-vectored bacterial pathogens centers on their life in the mammalian host, where disease occurs. However, disease outbreaks are driven by the arthropod vectors. Adapting to the arthropod is critical for obligate intracellular rickettsial pathogens, as they depend on eukaryotic cells for survival. To manipulate the intracellular environment, these bacteria use Type IV Secretion Systems (T4SS) to deliver effectors into the host cell. To date, few rickettsial T4SS translocated effectors have been identified and have only been examined in the context of mammalian infection. We identified an effector from the tick-borne rickettsial pathogen Anaplasma phagocytophilum , HGE1_02492, as critical for survival in tick cells and acquisition by ticks in vivo . Conversely, HGE1_02492 was dispensable during mammalian cell culture and murine infection. We show HGE1_02492 is translocatable in a T4SS-dependent manner to the host cell cytosol. In eukaryotic cells, the HGE1_02492 localized with cortical actin filaments, which is dependent on multiple sub-domains of the protein. HGE1_02492 is the first arthropod-vector specific T4SS translocated effector identified from a rickettsial pathogen. Moreover, the subcellular target of HGE1_02492 suggests that A. phagocytophilum is manipulating actin to enable arthropod colonization. Based on these findings, we propose the name AteA for Anaplasma ( phagocytophilum ) tick effector A. Altogether, we show that A. phagocytophilum uses distinct strategies to cycle between mammals and arthropods. Importance Ticks are the number one vector of pathogens for livestock worldwide and for humans in the US. The biology of tick transmission is an understudied area. Understanding this critical interaction could provide opportunities to affect the course of disease spread. In this study we examined the zoonotic tick-borne agent Anaplasma phagocytophilum and identified a secreted protein, AteA, that is expressed in a tick-specific manner. These secreted proteins, termed effectors, are the first proteins to interact with the host environment. AteA is essential for survival in ticks and appears to interact with cortical actin. Most effector proteins are studied in the context of the mammalian host; however, understanding how this unique set of proteins affect tick transmission is critical to developing interventions.
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12
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Helminiak L, Mishra S, Keun Kim H. Pathogenicity and virulence of Rickettsia. Virulence 2022; 13:1752-1771. [PMID: 36208040 PMCID: PMC9553169 DOI: 10.1080/21505594.2022.2132047] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 09/16/2022] [Accepted: 09/29/2022] [Indexed: 12/24/2022] Open
Abstract
Rickettsiae include diverse Gram-negative microbial species that exhibit obligatory intracellular lifecycles between mammalian hosts and arthropod vectors. Human infections with arthropod-borne Rickettsia continue to cause significant morbidity and mortality as recent environmental changes foster the proliferation of arthropod vectors and increased exposure to humans. However, the technical difficulties in working with Rickettsia have delayed our progress in understanding the molecular mechanisms involved in rickettsial pathogenesis and disease transmission. Recent advances in developing genetic tools for Rickettsia have enabled investigators to identify virulence genes, uncover molecular functions, and characterize host responses to rickettsial determinants. Therefore, continued efforts to determine virulence genes and their biological functions will help us understand the underlying mechanisms associated with arthropod-borne rickettsioses.
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Affiliation(s)
| | | | - Hwan Keun Kim
- Center for Infectious Diseases, Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, USA
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13
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Kramer DA, Piper HK, Chen B. WASP family proteins: Molecular mechanisms and implications in human disease. Eur J Cell Biol 2022; 101:151244. [PMID: 35667337 PMCID: PMC9357188 DOI: 10.1016/j.ejcb.2022.151244] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/25/2022] [Accepted: 05/27/2022] [Indexed: 02/08/2023] Open
Abstract
Proteins of the Wiskott-Aldrich syndrome protein (WASP) family play a central role in regulating actin cytoskeletal dynamics in a wide range of cellular processes. Genetic mutations or misregulation of these proteins are tightly associated with many diseases. The WASP-family proteins act by transmitting various upstream signals to their conserved WH2-Central-Acidic (WCA) peptide sequence at the C-terminus, which in turn binds to the Arp2/3 complex to stimulate the formation of branched actin networks at membranes. Despite this common feature, the regulatory mechanisms and cellular functions of distinct WASP-family proteins are very different. Here, we summarize and clarify our current understanding of WASP-family proteins and how disruption of their functions is related to human disease.
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Affiliation(s)
- Daniel A Kramer
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Hannah K Piper
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Baoyu Chen
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA.
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14
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Kim Y, Wang J, Clemens EG, Grab DJ, Dumler JS. Anaplasma phagocytophilum Ankyrin A Protein (AnkA) Enters the Nucleus Using an Importin-β-, RanGTP-Dependent Mechanism. Front Cell Infect Microbiol 2022; 12:828605. [PMID: 35719343 PMCID: PMC9204287 DOI: 10.3389/fcimb.2022.828605] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 04/20/2022] [Indexed: 12/30/2022] Open
Abstract
Anaplasma phagocytophilum, a tick-borne obligately intracellular bacterium of neutrophils, causes human granulocytic anaplasmosis. Ankyrin A (AnkA), an effector protein with multiple ankyrin repeats (AR) is injected via type IV-secretion into the host neutrophil to gain access to the nucleus where it modifies the epigenome to promote microbial fitness and propagation. AR proteins transported into the host cell nucleus must use at least one of two known eukaryotic pathways, the classical importin β-dependent pathway, and/or the RanGDP- and AR (ankyrin-repeat)-dependent importin β-independent (RaDAR) pathway. Truncation of the first four AnkA N-terminal ARs (AR1-4), but not other regions, prevents AnkA nuclear accumulation. To investigate the mechanism of nuclear import, we created point mutations of AnkA N-terminal ARs, predicted to interfere with RaDAR protein import, and used importazole, a specific inhibitor of the importin α/β, RanGTP-dependent pathway. Nuclear colocalization analysis shows that nuclear localization of AnkA is unaffected by single AR1-4 mutations but is significantly reduced by single mutations in consecutive ARs suggesting RaDAR protein nuclear import. However, AnkA nuclear localization was also decreased with importazole, and with GTPγS. Furthermore, A. phagocytophilum growth in HL-60 cells was completely suppressed with importazole, indicating that A. phagocytophilum propagation requires a β-importin-dependent pathway. A typical classical NLS overlapping AR4 was subsequently identified suggesting the primacy of the importin-α/β system in AnkA nuclear localization. Whether the mutational studies of putative key residues support RaDAR NLS function or simply reflect structural changes that diminish engagement of an AR-NLS-importin pathway needs to be resolved through careful structure-function studies.
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Affiliation(s)
- Yuri Kim
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States,Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States
| | - Jianyang Wang
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States,Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States
| | - Emily G. Clemens
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Dennis J. Grab
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - J. Stephen Dumler
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States,*Correspondence: J. Stephen Dumler,
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Matos AL, Curto P, Simões I. Moonlighting in Rickettsiales: Expanding Virulence Landscape. Trop Med Infect Dis 2022; 7:32. [PMID: 35202227 PMCID: PMC8877226 DOI: 10.3390/tropicalmed7020032] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/05/2022] [Accepted: 02/17/2022] [Indexed: 12/22/2022] Open
Abstract
The order Rickettsiales includes species that cause a range of human diseases such as human granulocytic anaplasmosis (Anaplasma phagocytophilum), human monocytic ehrlichiosis (Ehrlichia chaffeensis), scrub typhus (Orientia tsutsugamushi), epidemic typhus (Rickettsia prowazekii), murine typhus (R. typhi), Mediterranean spotted fever (R. conorii), or Rocky Mountain spotted fever (R. rickettsii). These diseases are gaining a new momentum given their resurgence patterns and geographical expansion due to the overall rise in temperature and other human-induced pressure, thereby remaining a major public health concern. As obligate intracellular bacteria, Rickettsiales are characterized by their small genome sizes due to reductive evolution. Many pathogens employ moonlighting/multitasking proteins as virulence factors to interfere with multiple cellular processes, in different compartments, at different times during infection, augmenting their virulence. The utilization of this multitasking phenomenon by Rickettsiales as a strategy to maximize the use of their reduced protein repertoire is an emerging theme. Here, we provide an overview of the role of various moonlighting proteins in the pathogenicity of these species. Despite the challenges that lie ahead to determine the multiple potential faces of every single protein in Rickettsiales, the available examples anticipate this multifunctionality as an essential and intrinsic feature of these obligates and should be integrated into available moonlighting repositories.
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Affiliation(s)
- Ana Luísa Matos
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (A.L.M.); (P.C.)
| | - Pedro Curto
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (A.L.M.); (P.C.)
| | - Isaura Simões
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (A.L.M.); (P.C.)
- IIIUC—Institute of Interdisciplinary Research, University of Coimbra, 3004-504 Coimbra, Portugal
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Cordsmeier A, Rinkel S, Jeninga M, Schulze-Luehrmann J, Ölke M, Schmid B, Hasler D, Meister G, Häcker G, Petter M, Beare PA, Lührmann A. The Coxiella burnetii T4SS effector protein AnkG hijacks the 7SK small nuclear ribonucleoprotein complex for reprogramming host cell transcription. PLoS Pathog 2022; 18:e1010266. [PMID: 35134097 PMCID: PMC8824381 DOI: 10.1371/journal.ppat.1010266] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 01/10/2022] [Indexed: 11/24/2022] Open
Abstract
Inhibition of host cell apoptosis is crucial for survival and replication of several intracellular bacterial pathogens. To interfere with apoptotic pathways, some pathogens use specialized secretion systems to inject bacterial effector proteins into the host cell cytosol. One of these pathogens is the obligate intracellular bacterium Coxiella burnetii, the etiological agent of the zoonotic disease Q fever. In this study, we analyzed the molecular activity of the anti-apoptotic T4SS effector protein AnkG (CBU0781) to understand how C. burnetii manipulates host cell viability. We demonstrate by co- and RNA-immunoprecipitation that AnkG binds to the host cell DExD box RNA helicase 21 (DDX21) as well as to the host cell 7SK small nuclear ribonucleoprotein (7SK snRNP) complex, an important regulator of the positive transcription elongation factor b (P-TEFb). The co-immunoprecipitation of AnkG with DDX21 is probably mediated by salt bridges and is independent of AnkG-7SK snRNP binding, and vice versa. It is known that DDX21 facilitates the release of P-TEFb from the 7SK snRNP complex. Consistent with the documented function of released P-TEFb in RNA Pol II pause release, RNA sequencing experiments confirmed AnkG-mediated transcriptional reprogramming and showed that expression of genes involved in apoptosis, trafficking, and transcription are influenced by AnkG. Importantly, DDX21 and P-TEFb are both essential for AnkG-mediated inhibition of host cell apoptosis, emphasizing the significance of the interaction of AnkG with both, the DDX21 protein and the 7SK RNA. In line with a critical function of AnkG in pathogenesis, the AnkG deletion C. burnetii strain was severely affected in its ability to inhibit host cell apoptosis and to generate a replicative C. burnetii-containing vacuole. In conclusion, the interference with the activity of regulatory host cell RNAs mediated by a bacterial effector protein represent a novel mechanism through which C. burnetii modulates host cell transcription, thereby enhancing permissiveness to bacterial infection. For intracellular replication, Coxiella burnetii depends on a functional type IV secretion system, which is utilized to inject ~150 virulence factors, so called effector proteins, into the host cell cytosol. Activities have only been established for few of them. These effector proteins interfere with vesicular trafficking, autophagy, lipid metabolism, apoptosis, and transcription by binding and manipulating the activity of host cell proteins. Here, we report that the C. burnetii T4SS effector protein AnkG (CBU0781, Q83DF6) binds to the host cell DExD box helicase 21 (DDX21) as well as to several host cell RNAs, including the small regulatory 7SK RNA, which is an important regulator of the positive elongation factor b (pTEFb). AnkG interferes with the function of the 7SK small nuclear ribonucleoprotein (7SK snRNP) complex, leading to significant changes in host cell transcription and ensuring host cell survival. AnkG activity is essential for efficient intracellular replication of C. burnetii and its ability to inhibit apoptosis. In summary, we identified a novel process by which a bacterial effector protein manipulates the host cell for its own benefit.
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Affiliation(s)
- Arne Cordsmeier
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Sven Rinkel
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Myriam Jeninga
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Jan Schulze-Luehrmann
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Martha Ölke
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Benedikt Schmid
- Lehrstuhl für Biotechnik, Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Daniele Hasler
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, Regensburg, Germany
| | - Gunter Meister
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, Regensburg, Germany
| | - Georg Häcker
- Faculty of Medicine, Institute of Medical Microbiology and Hygiene, Medical Center-University of Freiburg, Freiburg, Germany
| | - Michaela Petter
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Paul A. Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Anja Lührmann
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
- * E-mail:
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17
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Noroy C, Meyer DF. The super repertoire of type IV effectors in the pangenome of Ehrlichia spp. provides insights into host-specificity and pathogenesis. PLoS Comput Biol 2021; 17:e1008788. [PMID: 34252087 PMCID: PMC8274917 DOI: 10.1371/journal.pcbi.1008788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/26/2021] [Indexed: 11/28/2022] Open
Abstract
The identification of bacterial effectors is essential to understand how obligatory intracellular bacteria such as Ehrlichia spp. manipulate the host cell for survival and replication. Infection of mammals–including humans–by the intracellular pathogenic bacteria Ehrlichia spp. depends largely on the injection of virulence proteins that hijack host cell processes. Several hypothetical virulence proteins have been identified in Ehrlichia spp., but one so far has been experimentally shown to translocate into host cells via the type IV secretion system. However, the current challenge is to identify most of the type IV effectors (T4Es) to fully understand their role in Ehrlichia spp. virulence and host adaptation. Here, we predict the T4E repertoires of four sequenced Ehrlichia spp. and four other Anaplasmataceae as comparative models (pathogenic Anaplasma spp. and Wolbachia endosymbiont) using previously developed S4TE 2.0 software. This analysis identified 579 predicted T4Es (228 pT4Es for Ehrlichia spp. only). The effector repertoires of Ehrlichia spp. overlapped, thereby defining a conserved core effectome of 92 predicted effectors shared by all strains. In addition, 69 species-specific T4Es were predicted with non-canonical GC% mostly in gene sparse regions of the genomes and we observed a bias in pT4Es according to host-specificity. We also identified new protein domain combinations, suggesting novel effector functions. This work presenting the predicted effector collection of Ehrlichia spp. can serve as a guide for future functional characterisation of effectors and design of alternative control strategies against these bacteria. A fundamental step for the survival and replication of intravacuolar bacterial pathogens is the establishment of a replicative niche inside host cells by the secretion of bacterial effector proteins in the cytoplasm of the infected cells. These effectors manipulate host signaling pathways, thus allowing to escape the host degradative pathway and uptake nutrients required for intracellular replication of bacteria. In this study, we used S4TE2.0 software for high-throughput computational prediction of bacterial type IV effectors in zoonotic bacteria of the Anaplasmataceae family. The analysis of protein architecture of effectors helped us to identify the cellular pathways targeted during the infection process. The demonstration that effectors are modular components with a broad variety of protein architectures nicely explains their pleotropic mode of action and enlightens their function. We showed that bacterial adaptation to a given host during evolution requires a minimal repertoire of candidate effectors although further experimental determination is needed. T4Es are of increasing interest for basic research, including comprehension of hijacked cellular pathways, manipulated innate immunity, and application for therapeutics. Indeed pathogenomics-driven studies, especially on genetically intractable intracellular bacteria such as Anaplasmataceae, have now a substantial impact for the development of host-targeted antimicrobials, as an alternative to antibiotics.
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Affiliation(s)
- Christophe Noroy
- CIRAD, UMR ASTRE, Petit-Bourg, Guadeloupe, France
- ASTRE, CIRAD, INRA, Univ Montpellier, Montpellier, France
- Université des Antilles, Fouillole, Pointe-à-Pitre, Guadeloupe, France
| | - Damien F. Meyer
- CIRAD, UMR ASTRE, Petit-Bourg, Guadeloupe, France
- ASTRE, CIRAD, INRA, Univ Montpellier, Montpellier, France
- * E-mail:
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18
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Revisiting Ehrlichia ruminantium Replication Cycle Using Proteomics: The Host and the Bacterium Perspectives. Microorganisms 2021; 9:microorganisms9061144. [PMID: 34073568 PMCID: PMC8229282 DOI: 10.3390/microorganisms9061144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/28/2021] [Accepted: 05/07/2021] [Indexed: 12/16/2022] Open
Abstract
The Rickettsiales Ehrlichia ruminantium, the causal agent of the fatal tick-borne disease Heartwater, induces severe damage to the vascular endothelium in ruminants. Nevertheless, E. ruminantium-induced pathobiology remains largely unknown. Our work paves the way for understanding this phenomenon by using quantitative proteomic analyses (2D-DIGE-MS/MS, 1DE-nanoLC-MS/MS and biotin-nanoUPLC-MS/MS) of host bovine aorta endothelial cells (BAE) during the in vitro bacterium intracellular replication cycle. We detect 265 bacterial proteins (including virulence factors), at all time-points of the E. ruminantium replication cycle, highlighting a dynamic bacterium–host interaction. We show that E. ruminantium infection modulates the expression of 433 host proteins: 98 being over-expressed, 161 under-expressed, 140 detected only in infected BAE cells and 34 exclusively detected in non-infected cells. Cystoscape integrated data analysis shows that these proteins lead to major changes in host cell immune responses, host cell metabolism and vesicle trafficking, with a clear involvement of inflammation-related proteins in this process. Our findings led to the first model of E. ruminantium infection in host cells in vitro, and we highlight potential biomarkers of E. ruminantium infection in endothelial cells (such as ROCK1, TMEM16K, Albumin and PTPN1), which may be important to further combat Heartwater, namely by developing non-antibiotic-based strategies.
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Le LHM, Ying L, Ferrero RL. Nuclear trafficking of bacterial effector proteins. Cell Microbiol 2021; 23:e13320. [PMID: 33600054 DOI: 10.1111/cmi.13320] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 02/06/2023]
Abstract
Bacterial pathogens can subvert host responses by producing effector proteins that directly target the nucleus of eukaryotic cells in animals and plants. Nuclear-targeting proteins are categorised as either: "nucleomodulins," which have epigenetic-modulating activities; or "cyclomodulins," which specifically interfere with the host cell cycle. Bacteria can deliver these effector proteins to eukaryotic cells via a range of strategies. Despite an increasing number of reports describing the effects of bacterial effector proteins on nuclear processes in host cells, the intracellular pathways used by these proteins to traffic to the nucleus have yet to be fully elucidated. This review will describe current knowledge about how nucleomodulins and cyclomodulins enter eukaryotic cells, exploit endocytic pathways and translocate to the nucleus. We will also discuss the secretion of nuclear-targeting proteins or their release in bacterial membrane vesicles and the trafficking pathways employed by each of these forms. Besides their importance for bacterial pathogenesis, some nuclear-targeting proteins have been implicated in the development of chronic diseases and even cancer. A greater understanding of nuclear-targeting proteins and their actions will provide new insights into the pathogenesis of infectious diseases, as well as contribute to advances in the development of novel therapies against bacterial infections and possibly cancer.
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Affiliation(s)
- Lena Hoang My Le
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Biomedicine Discovery Institute, Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Le Ying
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Richard L Ferrero
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Biomedicine Discovery Institute, Department of Microbiology, Monash University, Melbourne, Victoria, Australia.,Department of Molecular and Translational Science, Monash University, Melbourne, Victoria, Australia
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20
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Lin M, Xiong Q, Chung M, Daugherty SC, Nagaraj S, Sengamalay N, Ott S, Godinez A, Tallon LJ, Sadzewicz L, Fraser C, Dunning Hotopp JC, Rikihisa Y. Comparative Analysis of Genome of Ehrlichia sp. HF, a Model Bacterium to Study Fatal Human Ehrlichiosis. BMC Genomics 2021; 22:11. [PMID: 33407096 PMCID: PMC7789307 DOI: 10.1186/s12864-020-07309-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 12/07/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The genus Ehrlichia consists of tick-borne obligatory intracellular bacteria that can cause deadly diseases of medical and agricultural importance. Ehrlichia sp. HF, isolated from Ixodes ovatus ticks in Japan [also referred to as I. ovatus Ehrlichia (IOE) agent], causes acute fatal infection in laboratory mice that resembles acute fatal human monocytic ehrlichiosis caused by Ehrlichia chaffeensis. As there is no small laboratory animal model to study fatal human ehrlichiosis, Ehrlichia sp. HF provides a needed disease model. However, the inability to culture Ehrlichia sp. HF and the lack of genomic information have been a barrier to advance this animal model. In addition, Ehrlichia sp. HF has several designations in the literature as it lacks a taxonomically recognized name. RESULTS We stably cultured Ehrlichia sp. HF in canine histiocytic leukemia DH82 cells from the HF strain-infected mice, and determined its complete genome sequence. Ehrlichia sp. HF has a single double-stranded circular chromosome of 1,148,904 bp, which encodes 866 proteins with a similar metabolic potential as E. chaffeensis. Ehrlichia sp. HF encodes homologs of all virulence factors identified in E. chaffeensis, including 23 paralogs of P28/OMP-1 family outer membrane proteins, type IV secretion system apparatus and effector proteins, two-component systems, ankyrin-repeat proteins, and tandem repeat proteins. Ehrlichia sp. HF is a novel species in the genus Ehrlichia, as demonstrated through whole genome comparisons with six representative Ehrlichia species, subspecies, and strains, using average nucleotide identity, digital DNA-DNA hybridization, and core genome alignment sequence identity. CONCLUSIONS The genome of Ehrlichia sp. HF encodes all known virulence factors found in E. chaffeensis, substantiating it as a model Ehrlichia species to study fatal human ehrlichiosis. Comparisons between Ehrlichia sp. HF and E. chaffeensis will enable identification of in vivo virulence factors that are related to host specificity, disease severity, and host inflammatory responses. We propose to name Ehrlichia sp. HF as Ehrlichia japonica sp. nov. (type strain HF), to denote the geographic region where this bacterium was initially isolated.
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Affiliation(s)
- Mingqun Lin
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH, 43210, USA.
| | - Qingming Xiong
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH, 43210, USA
| | - Matthew Chung
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Sean C Daugherty
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Sushma Nagaraj
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Naomi Sengamalay
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Sandra Ott
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Al Godinez
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Luke J Tallon
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Lisa Sadzewicz
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Claire Fraser
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
- Department of Medicine, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Julie C Dunning Hotopp
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
- Greenebaum Cancer Center, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Yasuko Rikihisa
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH, 43210, USA.
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21
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Bacterial Factors Targeting the Nucleus: The Growing Family of Nucleomodulins. Toxins (Basel) 2020; 12:toxins12040220. [PMID: 32244550 PMCID: PMC7232420 DOI: 10.3390/toxins12040220] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 03/23/2020] [Accepted: 03/29/2020] [Indexed: 12/18/2022] Open
Abstract
Pathogenic bacteria secrete a variety of proteins that manipulate host cell function by targeting components of the plasma membrane, cytosol, or organelles. In the last decade, several studies identified bacterial factors acting within the nucleus on gene expression or other nuclear processes, which has led to the emergence of a new family of effectors called “nucleomodulins”. In human and animal pathogens, Listeria monocytogenes for Gram-positive bacteria and Anaplasma phagocytophilum, Ehrlichia chaffeensis, Chlamydia trachomatis, Legionella pneumophila, Shigella flexneri, and Escherichia coli for Gram-negative bacteria, have led to pioneering discoveries. In this review, we present these paradigms and detail various mechanisms and core elements (e.g., DNA, histones, epigenetic regulators, transcription or splicing factors, signaling proteins) targeted by nucleomodulins. We particularly focus on nucleomodulins interacting with epifactors, such as LntA of Listeria and ankyrin repeat- or tandem repeat-containing effectors of Rickettsiales, and nucleomodulins from various bacterial species acting as post-translational modification enzymes. The study of bacterial nucleomodulins not only generates important knowledge about the control of host responses by microbes but also creates new tools to decipher the dynamic regulations that occur in the nucleus. This research also has potential applications in the field of biotechnology. Finally, this raises questions about the epigenetic effects of infectious diseases.
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22
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Matei IA, Estrada-Peña A, Cutler SJ, Vayssier-Taussat M, Varela-Castro L, Potkonjak A, Zeller H, Mihalca AD. A review on the eco-epidemiology and clinical management of human granulocytic anaplasmosis and its agent in Europe. Parasit Vectors 2019; 12:599. [PMID: 31864403 PMCID: PMC6925858 DOI: 10.1186/s13071-019-3852-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 12/13/2019] [Indexed: 11/11/2022] Open
Abstract
Anaplasma phagocytophilum is the agent of tick-borne fever, equine, canine and human granulocytic anaplasmosis. The common route of A. phagocytophilum transmission is through a tick bite, the main vector in Europe being Ixodes ricinus. Despite the apparently ubiquitous presence of the pathogen A. phagocytophilum in ticks and various wild and domestic animals from Europe, up to date published clinical cases of human granulocytic anaplasmosis (HGA) remain rare compared to the worldwide status. It is unclear if this reflects the epidemiological dynamics of the human infection in Europe or if the disease is underdiagnosed or underreported. Epidemiologic studies in Europe have suggested an increased occupational risk of infection for forestry workers, hunters, veterinarians, and farmers with a tick-bite history and living in endemic areas. Although the overall genetic diversity of A. phagocytophilum in Europe is higher than in the USA, the strains responsible for the human infections are related on both continents. However, the study of the genetic variability and assessment of the difference of pathogenicity and infectivity between strains to various hosts has been insufficiently explored to date. Most of the European HGA cases presented as a mild infection, common clinical signs being pyrexia, headache, myalgia and arthralgia. The diagnosis of HGA in the USA was recommended to be based on clinical signs and the patient’s history and later confirmed using specialized laboratory tests. However, in Europe since the majority of cases are presenting as mild infection, laboratory tests may be performed before the treatment in order to avoid antibiotic overuse. The drug of choice for HGA is doxycycline and because of potential for serious complication the treatment should be instituted on clinical suspicion alone.
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Affiliation(s)
- Ioana A Matei
- Department of Parasitology and Parasitic Diseases, Faculty of Veterinary Medicine, University of Agricultural Science and Veterinary Medicine Cluj-Napoca, Cluj-Napoca, Romania
| | - Agustín Estrada-Peña
- Department of Animal Health, Faculty of Veterinary Medicine, University of Zaragoza, Zaragoza, Spain
| | - Sally J Cutler
- School of Health, Sport & Bioscience, University of East London, London, UK.
| | - Muriel Vayssier-Taussat
- Department of Animal Health, French National Institute for Agricultural Research, Maisons-Alfort, France
| | - Lucía Varela-Castro
- Department of Animal Health, Faculty of Veterinary Medicine, University of Zaragoza, Zaragoza, Spain.,Animal Health Department, NEIKER-Instituto Vasco de Investigación y Desarrollo Agrario, Bizkaia Science and Technology Park, Derio, Bizkaia, Spain
| | - Aleksandar Potkonjak
- Department of Veterinary Medicine, Faculty of Agriculture, University of Novi Sad, Novi Sad, Serbia
| | - Herve Zeller
- Emerging and Vector-borne Diseases Programme, European Centre for Disease Prevention and Control, Solna, Sweden
| | - Andrei D Mihalca
- Department of Parasitology and Parasitic Diseases, Faculty of Veterinary Medicine, University of Agricultural Science and Veterinary Medicine Cluj-Napoca, Cluj-Napoca, Romania
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23
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Host-Targeted Therapeutics against Multidrug Resistant Intracellular Staphylococcus aureus. Antibiotics (Basel) 2019; 8:antibiotics8040241. [PMID: 31795127 PMCID: PMC6963206 DOI: 10.3390/antibiotics8040241] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/21/2019] [Accepted: 11/25/2019] [Indexed: 12/14/2022] Open
Abstract
Staphylococcus aureus is a facultative intracellular pathogen that invades and replicates within many types of human cells. S. aureus has shown to rapidly overcome traditional antibiotherapy by developing multidrug resistance. Furthermore, intracellular S. aureus is protected from the last-resort antibiotics—vancomycin, daptomycin, and linezolid—as they are unable to achieve plasma concentrations sufficient for intracellular killing. Therefore, there is an urgent need to develop novel anti-infective therapies against S. aureus infections. Here, we review the current state of the field and highlight the exploitation of host-directed approaches as a promising strategy going forward.
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24
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Sinha A, Li Z, Sun L, Carlow CKS. Complete Genome Sequence of the Wolbachia wAlbB Endosymbiont of Aedes albopictus. Genome Biol Evol 2019; 11:706-720. [PMID: 30715337 PMCID: PMC6414309 DOI: 10.1093/gbe/evz025] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/29/2019] [Indexed: 12/21/2022] Open
Abstract
Wolbachia, an alpha-proteobacterium closely related to Rickettsia, is a maternally transmitted, intracellular symbiont of arthropods and nematodes. Aedes albopictus mosquitoes are naturally infected with Wolbachia strains wAlbA and wAlbB. Cell line Aa23 established from Ae. albopictus embryos retains only wAlbB and is a key model to study host–endosymbiont interactions. We have assembled the complete circular genome of wAlbB from the Aa23 cell line using long-read PacBio sequencing at 500× median coverage. The assembled circular chromosome is 1.48 megabases in size, an increase of more than 300 kb over the published draft wAlbB genome. The annotation of the genome identified 1,205 protein coding genes, 34 tRNA, 3 rRNA, 1 tmRNA, and 3 other ncRNA loci. The long reads enabled sequencing over complex repeat regions which are difficult to resolve with short-read sequencing. Thirteen percent of the genome comprised insertion sequence elements distributed throughout the genome, some of which cause pseudogenization. Prophage WO genes encoding some essential components of phage particle assembly are missing, while the remainder are found in five prophage regions/WO-like islands or scattered around the genome. Orthology analysis identified a core proteome of 535 orthogroups across all completed Wolbachia genomes. The majority of proteins could be annotated using Pfam and eggNOG analyses, including ankyrins and components of the Type IV secretion system. KEGG analysis revealed the absence of five genes in wAlbB which are present in other Wolbachia. The availability of a complete circular chromosome from wAlbB will enable further biochemical, molecular, and genetic analyses on this strain and related Wolbachia.
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Affiliation(s)
- Amit Sinha
- New England Biolabs, Ipswich, Massachusetts
| | - Zhiru Li
- New England Biolabs, Ipswich, Massachusetts
| | - Luo Sun
- New England Biolabs, Ipswich, Massachusetts
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25
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Role and Function of the Type IV Secretion System in Anaplasma and Ehrlichia Species. Curr Top Microbiol Immunol 2019; 413:297-321. [PMID: 29536364 DOI: 10.1007/978-3-319-75241-9_12] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The obligatory intracellular pathogens Anaplasma phagocytophilum and Ehrlichia chaffeensis proliferate within membrane-bound vacuoles of human leukocytes and cause potentially fatal emerging infectious diseases. Despite the reductive genome evolution in this group of bacteria, genes encoding the type IV secretion system (T4SS), which is homologous to the VirB/VirD4 system of the plant pathogen Agrobacterium tumefaciens, have been expanded and are highly expressed in A. phagocytophilum and E. chaffeensis in human cells. Of six T4SS effector proteins identified in them, roles and functions have been described so far only for ankyrin repeat domain-containing protein A (AnkA), Anaplasma translocated substrate 1 (Ats-1), and Ehrlichia translocated factor 1 (Etf-1, ECH0825). These effectors are abundantly produced and secreted into the host cytoplasm during infection, but not toxic to host cells. They contain eukaryotic protein motifs or organelle localization signals and have distinct subcellular localization, target to specific host cell molecules to promote infection. Ats-1 and Etf-1 are orthologous proteins, subvert two important innate immune mechanisms against intracellular infection, cellular apoptosis and autophagy, and manipulate autophagy to gain nutrients from host cells. Although Ats-1 and Etf-1 have similar functions and roles in obligatory intracellular infection, they are specifically adapted to the distinct membrane-bound intracellular niche of A. phagocytophilum and E. chaffeensis, respectively. Ectopic expression of these effectors enhances respective bacterial infection, whereas intracellular delivery of antibodies against these effectors or targeted knockdown of the effector with antisense peptide nucleic acid significantly impairs bacterial infection. Thus, both T4SSs have evolved as important survival and nutritional virulence mechanism in these obligatory intracellular bacteria. Future studies on the functions of Anaplasma and Ehrlichia T4SS effector molecules and signaling pathways will undoubtedly advance our understanding of the complex interplay between obligatory intracellular pathogens and their hosts. Such data can be applied toward the treatment and control of anaplasmosis and ehrlichiosis.
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26
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Infection by Anaplasma phagocytophilum Requires Recruitment of Low-Density Lipoprotein Cholesterol by Flotillins. mBio 2019; 10:mBio.02783-18. [PMID: 30914515 PMCID: PMC6437059 DOI: 10.1128/mbio.02783-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Anaplasma phagocytophilum is an obligatory intracellular bacterium that proliferates in membrane-bound inclusions. A. phagocytophilum is dependent on cholesterol and acquire cholesterol from low-density lipoprotein (LDL) endocytosed by mammalian host cells. The mechanism of cholesterol transport to Anaplasma inclusions, however, is not fully understood. Flotillin-1 (FLOT1) and FLOT2 are cholesterol-associated membrane proteins that form a heterodimer and/or oligomer complex. Here, we found that Anaplasma infection was significantly reduced by small interfering RNA (siRNA) knockdown of FLOT1 or FLOT2. Anaplasma inclusions were encircled with small vesicles containing endogenous FLOT1 or FLOT2 or with ectopically expressed FLOT1-mCherry and FLOT2-green fluorescent protein (FLOT2-GFP). FLOT1- and FLOT2-containing vesicles were enriched with unesterified cholesterol, as indicated by labeling with filipin and aminomethyl coumarin acetic acid-conjugated theonellamide. Localization of FLOT2 to Anaplasma inclusions was dependent on cholesterol, as FLOT2-GFP bearing two mutations in the cholesterol recognition/interaction motif could not target the inclusions. The cholesterol-sequestering agent methyl-β-cyclodextrin abrogated FLOT1 localization to Anaplasma inclusions and cleared infection. FLOT2-GFP also localized to fluorescent 3,3'-dioctadecylindocarbocyanine (DiI)-LDL-containing vesicles, including those surrounding Anaplasma inclusions. FLOT2 siRNA knockdown blocked DiI-LDL trafficking to Anaplasma inclusions and reduced bacteria-associated cholesterol amount, and therefore inhibiting Anaplasma infection. Vesicles containing acid lipase, which hydrolyzes LDL cholesterol esters to free cholesterol, colocalized with FLOT2 and encircled Anaplasma inclusions, while the acid lipase inhibitor orlistat significantly inhibited Anaplasma replication. Together, the data revealed that FLOTs are crucial for Anaplasma replication in host cells, likely by aiding vesicular traffic of LDL-derived free cholesterol to Anaplasma inclusions, and suggest a new way of inhibiting Anaplasma infection.IMPORTANCE Cholesterol is essential for animal cells, but most bacteria do not depend on cholesterol and instead lack cholesterol. However, the intracellular Gram-negative bacterium Anaplasma phagocytophilum that causes human granulocytic anaplasmosis (HGA) is unusual, as it contains significant amount of cholesterol and depends on cholesterol for survival and infection. A. phagocytophilum lacks genes for cholesterol biosynthesis or modification but acquire cholesterol from host cells exclusively from the LDL uptake pathway by a yet-to-be defined mechanism. Here, we uncovered a role of cholesterol-binding proteins FLOT1 and FLOT2 in LDL-derived cholesterol trafficking to Anaplasma inclusions and cholesterol acquisition by Anaplasma species. Importantly, we found that FLOTs localize to A. phagocytophilum-containing inclusions and the compartments containing LDL, and the acid lipase inhibitor orlistat significantly inhibits Anaplasma replication. Our data suggest a fundamental role of FLOTs in intracellular vesicular transport of LDL-derived free cholesterol and may provide insight regarding a new therapeutic target for HGA treatment.
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27
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Marcelino I, Colomé-Calls N, Holzmuller P, Lisacek F, Reynaud Y, Canals F, Vachiéry N. Sweet and Sour Ehrlichia: Glycoproteomics and Phosphoproteomics Reveal New Players in Ehrlichia ruminantium Physiology and Pathogenesis. Front Microbiol 2019; 10:450. [PMID: 30930869 PMCID: PMC6429767 DOI: 10.3389/fmicb.2019.00450] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 02/20/2019] [Indexed: 01/31/2023] Open
Abstract
Unraveling which proteins and post-translational modifications (PTMs) affect bacterial pathogenesis and physiology in diverse environments is a tough challenge. Herein, we used mass spectrometry-based assays to study protein phosphorylation and glycosylation in Ehrlichia ruminantium Gardel virulent (ERGvir) and attenuated (ERGatt) variants and, how they can modulate Ehrlichia biological processes. The characterization of the S/T/Y phosphoproteome revealed that both strains share the same set of phosphoproteins (n = 58), 36% being overexpressed in ERGvir. The percentage of tyrosine phosphorylation is high (23%) and 66% of the identified peptides are multi-phosphorylated. Glycoproteomics revealed a high percentage of glycoproteins (67% in ERGvir) with a subset of glycoproteins being specific to ERGvir (n = 64/371) and ERGatt (n = 36/343). These glycoproteins are involved in key biological processes such as protein, amino-acid and purine biosynthesis, translation, virulence, DNA repair, and replication. Label-free quantitative analysis revealed over-expression in 31 proteins in ERGvir and 8 in ERGatt. While further PNGase digestion confidently localized 2 and 5 N-glycoproteins in ERGvir and ERGatt, respectively, western blotting suggests that many glycoproteins are O-GlcNAcylated. Twenty-three proteins were detected in both the phospho- and glycoproteome, for the two variants. This work represents the first comprehensive assessment of PTMs on Ehrlichia biology, rising interesting questions regarding ER–host interactions. Phosphoproteome characterization demonstrates an increased versatility of ER phosphoproteins to participate in different mechanisms. The high number of glycoproteins and the lack of glycosyltransferases-coding genes highlight ER dependence on the host and/or vector cellular machinery for its own protein glycosylation. Moreover, these glycoproteins could be crucial to interact and respond to changes in ER environment. PTMs crosstalk between of O-GlcNAcylation and phosphorylation could be used as a major cellular signaling mechanism in ER. As little is known about the Ehrlichia proteins/proteome and its signaling biology, the results presented herein provide a useful resource for further hypothesis-driven exploration of Ehrlichia protein regulation by phosphorylation and glycosylation events. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium with the data set identifier PXD012589.
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Affiliation(s)
- Isabel Marcelino
- CIRAD, UMR ASTRE, Petit-Bourg, France.,ASTRE, CIRAD, INRA, Université de Montpellier, Montpellier, France.,Unitè TReD-Path (Transmission Rèservoirs et Diversitè des Pathogènes), Institut Pasteur de Guadeloupe, Les Abymes, France
| | - Núria Colomé-Calls
- Proteomics Laboratory, Vall Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Philippe Holzmuller
- ASTRE, CIRAD, INRA, Université de Montpellier, Montpellier, France.,CIRAD, UMR ASTRE, Montpellier, France
| | - Frédérique Lisacek
- Proteome Informatics, Swiss Institute of Bioinformatics, Geneva, Switzerland.,Computer Science Department and Section of Biology, University of Geneva, Geneva, Switzerland
| | - Yann Reynaud
- Unitè TReD-Path (Transmission Rèservoirs et Diversitè des Pathogènes), Institut Pasteur de Guadeloupe, Les Abymes, France
| | - Francesc Canals
- Proteomics Laboratory, Vall Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Nathalie Vachiéry
- ASTRE, CIRAD, INRA, Université de Montpellier, Montpellier, France.,CIRAD, UMR ASTRE, Montpellier, France
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28
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Zhu J, He M, Xu W, Li Y, Huang R, Wu S, Niu H. Development of TEM-1 β-lactamase based protein translocation assay for identification of Anaplasma phagocytophilum type IV secretion system effector proteins. Sci Rep 2019; 9:4235. [PMID: 30862835 PMCID: PMC6414681 DOI: 10.1038/s41598-019-40682-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 02/20/2019] [Indexed: 11/24/2022] Open
Abstract
Anaplasma phagocytophilum, the aetiologic agent of human granulocytic anaplasmosis (HGA) is an obligate intracellular Gram-negative bacterium with the genome size of 1.47 megabases. The intracellular life style and small size of genome suggest that A. phagocytophilum has to modulate a multitude of host cell physiological processes to facilitate its replication. One strategy employed by A. phagocytophilum is through its type IV secretion system (T4SS), which translocates bacterial effectors into target cells to disrupt normal cellular activities. In this study we developed a TEM-1 β-lactamase based protein translocation assay and applied this assay for identification of A. phagocytophilum T4SS effectors. An A. phagocytophilum hypothetical protein, APH0215 is identified as a T4SS effector protein and found interacting with trans-Golgi network in transfected cells. Hereby, this protein translocation assay developed in this study will facilitate the identification of A. phagocytophilum T4SS effectors and elucidation of HGA pathogenesis.
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Affiliation(s)
- Jiafeng Zhu
- Department of Microbiology, College of Medicine, Soochow University, Suzhou, Jiangsu Province, 215123, China
| | - Meiling He
- Department of Microbiology, College of Medicine, Soochow University, Suzhou, Jiangsu Province, 215123, China
| | - Wenting Xu
- Department of Microbiology, College of Medicine, Soochow University, Suzhou, Jiangsu Province, 215123, China
| | - Yuanyuan Li
- Department of Microbiology, College of Medicine, Soochow University, Suzhou, Jiangsu Province, 215123, China
| | - Rui Huang
- Department of Microbiology, College of Medicine, Soochow University, Suzhou, Jiangsu Province, 215123, China
| | - Shuyan Wu
- Department of Microbiology, College of Medicine, Soochow University, Suzhou, Jiangsu Province, 215123, China
| | - Hua Niu
- Department of Microbiology, College of Medicine, Soochow University, Suzhou, Jiangsu Province, 215123, China.
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29
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López V, Alberdi P, Fuente JDL. Common Strategies, Different Mechanisms to Infect the Host: Anaplasma and Mycobacterium. Tuberculosis (Edinb) 2018. [DOI: 10.5772/intechopen.71535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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30
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Identification of novel immunoreactive proteins and delineation of a specific epitope of Anaplasma phagocytophilum. Microb Pathog 2018; 125:183-188. [PMID: 30217516 DOI: 10.1016/j.micpath.2018.09.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 08/27/2018] [Accepted: 09/11/2018] [Indexed: 01/09/2023]
Abstract
Human granulocytic anaplasmosis (HGA), an increasingly recognized febrile tick-borne illness, is caused by a gram-negative obligate intracellular bacterium Anaplasma phagocytophilum. Because of nonspecific clinical manifestations, diagnosis of HGA highly depends on laboratory tests. Identification of immunoreactive proteins is prerequisite for development of specific and sensitive immunoassays for HGA. In this study, we identified novel immunoreactive proteins of A. phagocytophilum. Previous studies indicated that secreted proteins of A. phagocytophilum and other bacteria can be immunoreactive antigens. Here we in silico screened A. phagocytophilum genome for encoding proteins which bear features of type IV secretion system substrates. Among seventy seven predicted proteins, fourteen proteins were determined for antigenicity and nine proteins were showed to be immunoreactive antigens. In addition, an APH1384 peptide harboring a B cell epitope predicted by bioinformatics was found specifically reacting with anti-A. phagocytophilum sera. Hereby, we identified novel immunoreactive proteins and delineated a specific epitope of A. phagocytophilum, which might be employed for HGA diagnosis.
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31
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The Rickettsial Ankyrin Repeat Protein 2 Is a Type IV Secreted Effector That Associates with the Endoplasmic Reticulum. mBio 2018; 9:mBio.00975-18. [PMID: 29946049 PMCID: PMC6020290 DOI: 10.1128/mbio.00975-18] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Strains of Rickettsia rickettsii, the tick-borne agent of Rocky Mountain spotted fever, vary considerably in virulence. Genomic comparisons of R. rickettsii strains have identified a relatively small number of genes divergent in an avirulent strain. Among these is one annotated as Rickettsia ankyrin repeat protein 2 (RARP-2). Homologs of RARP-2 are present in all strains of R. rickettsii, but the protein in the avirulent strain Iowa contains a large internal deletion relative to the virulent Sheila Smith strain. RARP-2 is secreted in a type IV secretion system-dependent manner and exposed to the host cell cytosol. RARP-2 of Sheila Smith colocalizes with multilamellar membranous structures bearing markers of the endoplasmic reticulum (ER), whereas the Iowa protein shows no colocalization with host cell organelles and evidence of proteolytic degradation is detected. Overexpression of Sheila Smith RARP-2 in R. rickettsii Iowa converts this avirulent strain’s typically nonlytic or opaque plaque type to a lytic plaque phenotype similar to that of the virulent Sheila Smith strain. Mutation of a predicted proteolytic active site of Sheila Smith RARP-2 abolished the lytic plaque phenotype but did not eliminate association with host membrane. RARP-2 is thus a type IV secreted effector and released from the rickettsiae into the host cytosol to modulate host processes during infection. Overexpression of Sheila Smith RARP-2 did not, however, restore the virulence of the Iowa strain in a guinea pig model, likely due to the multifactorial nature of rickettsial virulence. Members of the genus Rickettsia are obligate intracellular bacteria that exhibit a range of virulence from harmless endosymbionts of arthropods to the etiologic agents of severe disease. Despite the growing number of available genomes, little is known regarding virulence determinants of rickettsiae. Here, we have characterized an ankyrin repeat-containing protein, RARP-2, which differs between a highly virulent and an avirulent strain of R. rickettsii, the agent of Rocky Mountain spotted fever. RARP-2 is secreted by a type IV secretion system into the cytosol of the host cell, where it interacts with and manipulates the structure of the endoplasmic reticulum. RARP-2 from the avirulent strain is truncated by the loss of seven of 10 ankyrin repeat units but, although secreted, fails to alter ER structure. Recognition of those rickettsial factors associated with virulence will facilitate understanding of regional and strain-specific variation in severity of disease.
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32
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Scorpio DG, Choi KS, Dumler JS. Anaplasma phagocytophilum-Related Defects in CD8, NKT, and NK Lymphocyte Cytotoxicity. Front Immunol 2018; 9:710. [PMID: 29686681 PMCID: PMC5900440 DOI: 10.3389/fimmu.2018.00710] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 03/22/2018] [Indexed: 12/19/2022] Open
Abstract
Human granulocytic anaplasmosis, caused by the tick-transmitted Anaplasma phagocytophilum, is not controlled by innate immunity, and induces a proinflammatory disease state with innate immune cell activation. In A. phagocytophilum murine infection models, hepatic injury occurs with production of IFNγ thought to be derived from NK, NKT cells, and CD8 T lymphocytes. Specific A. phagocytophilum ligands that drive inflammation and disease are not known, but suggest a clinical and pathophysiologic basis strikingly like macrophage activation syndrome (MAS) and hemophagocytic syndrome (HPS). We studied in vivo responses of NK, NKT, and CD8 T lymphocytes from infected animals for correlates of lymphocyte-mediated cytotoxicity and examined in vitro interactions with A. phagocytophilum-loaded antigen-presenting cells (APCs). Murine splenocytes were examined and found deficient in cytotoxicity as determined by CD107a expression in vitro for specific CTL effector subsets as determined by flow cytometry. Moreover, A. phagocytophilum-loaded APCs did not lead to IFNγ production among CTLs in vitro. These findings support the concept of impaired cytotoxicity with A. phagocytophilum presentation by APCs that express MHC class I and that interact with innate and adaptive immune cells with or after infection. The findings strengthen the concept of an enhanced proinflammatory phenotype, such as MAS and HPS disease states as the basis of disease and severity with A. phagocytophilum infection, and perhaps by other obligate intracellular bacteria.
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Affiliation(s)
- Diana G Scorpio
- Vaccine Research Center, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Kyoung-Seong Choi
- College of Ecology and Environmental Science, Kyungpook National University, Sangju, South Korea
| | - J Stephen Dumler
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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33
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Dumler JS, Sinclair SH, Shetty AC. Alternative Splicing of Differentiated Myeloid Cell Transcripts after Infection by Anaplasma phagocytophilum Impacts a Selective Group of Cellular Programs. Front Cell Infect Microbiol 2018; 8:14. [PMID: 29456968 PMCID: PMC5801399 DOI: 10.3389/fcimb.2018.00014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 01/12/2018] [Indexed: 12/21/2022] Open
Abstract
Eukaryotic proteome diversity exceeds that encoded within individual genes, and results in part from alternative splicing events of pre-messenger RNA. The diversity of these splicing events can shape the outcome in development and differentiation of normal tissues, and is important in pathogenic circumstances such as cancer and some heritable conditions. A role for alternative splicing of eukaryotic genes in response to viral and intracellular bacterial infections has only recently been recognized, and plays an important role in providing fitness for microbial survival, while potentially enhancing pathogenicity. Anaplasma phagocytophilum survives within mammalian neutrophils by reshaping transcriptional programs that govern cellular functions. We applied next generation RNAseq to ATRA-differentiated HL-60 cells established to possess transcriptional and functional responses similar to A. phagocytophilum-infected human neutrophils. This demonstrated an increase in transcripts with infection and high proportion of alternatively spliced transcript events (ASEs) for which predicted gene ontology processes were in part distinct from those identified by evaluation of single transcripts or gene-level analyses alone. The alternative isoforms are not on average shorter, and no alternative splicing in genes encoding spliceosome components is noted. Although not evident at gene-level analyses, individual spliceosome transcripts that impact nearly all spliceosome components were significantly upregulated. How the distinct GO processes predicted by ASEs are regulated by infection and whether they are relevant to fitness or pathogenicity of A. phagocytophilum should be addressed in more detailed studies.
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Affiliation(s)
- J Stephen Dumler
- Department of Pathology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | | | - Amol C Shetty
- Institute for Genome Sciences, University of Maryland, Baltimore, Baltimore, MD, United States
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34
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Grohmann E, Christie PJ, Waksman G, Backert S. Type IV secretion in Gram-negative and Gram-positive bacteria. Mol Microbiol 2018; 107:455-471. [PMID: 29235173 PMCID: PMC5796862 DOI: 10.1111/mmi.13896] [Citation(s) in RCA: 225] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/07/2017] [Accepted: 12/09/2017] [Indexed: 02/06/2023]
Abstract
Type IV secretion systems (T4SSs) are versatile multiprotein nanomachines spanning the entire cell envelope in Gram-negative and Gram-positive bacteria. They play important roles through the contact-dependent secretion of effector molecules into eukaryotic hosts and conjugative transfer of mobile DNA elements as well as contact-independent exchange of DNA with the extracellular milieu. In the last few years, many details on the molecular mechanisms of T4SSs have been elucidated. Exciting structures of T4SS complexes from Escherichia coli plasmids R388 and pKM101, Helicobacter pylori and Legionella pneumophila have been solved. The structure of the F-pilus was also reported and surprisingly revealed a filament composed of pilin subunits in 1:1 stoichiometry with phospholipid molecules. Many new T4SSs have been identified and characterized, underscoring the structural and functional diversity of this secretion superfamily. Complex regulatory circuits also have been shown to control T4SS machine production in response to host cell physiological status or a quorum of bacterial recipient cells in the vicinity. Here, we summarize recent advances in our knowledge of 'paradigmatic' and emerging systems, and further explore how new basic insights are aiding in the design of strategies aimed at suppressing T4SS functions in bacterial infections and spread of antimicrobial resistances.
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Affiliation(s)
- Elisabeth Grohmann
- Beuth University of Applied Sciences Berlin, Life Sciences and Technology, D-13347 Berlin, Germany
| | - Peter J. Christie
- Department of Microbiology and Molecular Genetics, The University of Texas Medical School at Houston, 6431 Fannin St, Houston, Texas 77030, USA
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, London WC1E 7HX, United Kingdom
| | - Steffen Backert
- Friedrich Alexander University Erlangen-Nuremberg, Department of Biology, Division of Microbiology, Staudtstrasse 5, D-91058 Erlangen, Germany
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Contreras M, Alberdi P, Mateos-Hernández L, Fernández de Mera IG, García-Pérez AL, Vancová M, Villar M, Ayllón N, Cabezas-Cruz A, Valdés JJ, Stuen S, Gortazar C, de la Fuente J. Anaplasma phagocytophilum MSP4 and HSP70 Proteins Are Involved in Interactions with Host Cells during Pathogen Infection. Front Cell Infect Microbiol 2017; 7:307. [PMID: 28725639 PMCID: PMC5496961 DOI: 10.3389/fcimb.2017.00307] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 06/20/2017] [Indexed: 12/18/2022] Open
Abstract
Anaplasma phagocytophilum transmembrane and surface proteins play a role during infection and multiplication in host neutrophils and tick vector cells. Recently, A. phagocytophilum Major surface protein 4 (MSP4) and Heat shock protein 70 (HSP70) were shown to be localized on the bacterial membrane, with a possible role during pathogen infection in ticks. In this study, we hypothesized that A. phagocytophilum MSP4 and HSP70 have similar functions in tick-pathogen and host-pathogen interactions. To address this hypothesis, herein we characterized the role of these bacterial proteins in interaction and infection of vertebrate host cells. The results showed that A. phagocytophilum MSP4 and HSP70 are involved in host-pathogen interactions, with a role for HSP70 during pathogen infection. The analysis of the potential protective capacity of MSP4 and MSP4-HSP70 antigens in immunized sheep showed that MSP4-HSP70 was only partially protective against pathogen infection. This limited protection may be associated with several factors, including the recognition of non-protective epitopes by IgG in immunized lambs. Nevertheless, these antigens may be combined with other candidate protective antigens for the development of vaccines for the control of human and animal granulocytic anaplasmosis. Focusing on the characterization of host protective immune mechanisms and protein-protein interactions at the host-pathogen interface may lead to the discovery and design of new effective protective antigens.
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Affiliation(s)
- Marinela Contreras
- SaBio, Instituto de Investigación en Recursos Cinegéticos, Consejo Superior de Investigaciones Científicas, CSIC-UCLM-JCCMCiudad Real, Spain
| | - Pilar Alberdi
- SaBio, Instituto de Investigación en Recursos Cinegéticos, Consejo Superior de Investigaciones Científicas, CSIC-UCLM-JCCMCiudad Real, Spain
| | - Lourdes Mateos-Hernández
- SaBio, Instituto de Investigación en Recursos Cinegéticos, Consejo Superior de Investigaciones Científicas, CSIC-UCLM-JCCMCiudad Real, Spain
| | - Isabel G Fernández de Mera
- SaBio, Instituto de Investigación en Recursos Cinegéticos, Consejo Superior de Investigaciones Científicas, CSIC-UCLM-JCCMCiudad Real, Spain
| | - Ana L García-Pérez
- Departamento de Sanidad Animal, Instituto Vasco de Investigación y Desarrollo Agrario (NEIKER)Derio, Spain
| | - Marie Vancová
- Biology Centre, Czech Academy of Sciences, Institute of ParasitologyČeské Budějovice, Czechia.,Faculty of Science, University of South BohemiaČeské Budějovice, Czechia
| | - Margarita Villar
- SaBio, Instituto de Investigación en Recursos Cinegéticos, Consejo Superior de Investigaciones Científicas, CSIC-UCLM-JCCMCiudad Real, Spain
| | - Nieves Ayllón
- SaBio, Instituto de Investigación en Recursos Cinegéticos, Consejo Superior de Investigaciones Científicas, CSIC-UCLM-JCCMCiudad Real, Spain
| | - Alejandro Cabezas-Cruz
- Biology Centre, Czech Academy of Sciences, Institute of ParasitologyČeské Budějovice, Czechia.,Faculty of Science, University of South BohemiaČeské Budějovice, Czechia.,UMR BIPAR, Animal Health Laboratory, INRA, ANSES, ENVAMaisons Alfort, France
| | - James J Valdés
- Biology Centre, Czech Academy of Sciences, Institute of ParasitologyČeské Budějovice, Czechia.,Department of Virology, Veterinary Research InstituteBrno, Czechia
| | - Snorre Stuen
- Department of Production Animal Clinical Sciences, Norwegian University of Life SciencesSandnes, Norway
| | - Christian Gortazar
- SaBio, Instituto de Investigación en Recursos Cinegéticos, Consejo Superior de Investigaciones Científicas, CSIC-UCLM-JCCMCiudad Real, Spain
| | - José de la Fuente
- SaBio, Instituto de Investigación en Recursos Cinegéticos, Consejo Superior de Investigaciones Científicas, CSIC-UCLM-JCCMCiudad Real, Spain.,Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State UniversityStillwater, OK, United States
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Sollero BP, Junqueira VS, Gomes CCG, Caetano AR, Cardoso FF. Tag SNP selection for prediction of tick resistance in Brazilian Braford and Hereford cattle breeds using Bayesian methods. Genet Sel Evol 2017; 49:49. [PMID: 28619006 PMCID: PMC5471684 DOI: 10.1186/s12711-017-0325-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 05/31/2017] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Cattle resistance to ticks is known to be under genetic control with a complex biological mechanism within and among breeds. Our aim was to identify genomic segments and tag single nucleotide polymorphisms (SNPs) associated with tick-resistance in Hereford and Braford cattle. The predictive performance of a very low-density tag SNP panel was estimated and compared with results obtained with a 50 K SNP dataset. RESULTS BayesB (π = 0.99) was initially applied in a genome-wide association study (GWAS) for this complex trait by using deregressed estimated breeding values for tick counts and 41,045 SNP genotypes from 3455 animals raised in southern Brazil. To estimate the combined effect of a genomic region that is potentially associated with quantitative trait loci (QTL), 2519 non-overlapping 1-Mb windows that varied in SNP number were defined, with the top 48 windows including 914 SNPs and explaining more than 20% of the estimated genetic variance for tick resistance. Subsequently, the most informative SNPs were selected based on Bayesian parameters (model frequency and t-like statistics), linkage disequilibrium and minor allele frequency to propose a very low-density 58-SNP panel. Some of these tag SNPs mapped close to or within genes and pseudogenes that are functionally related to tick resistance. Prediction ability of this SNP panel was investigated by cross-validation using K-means and random clustering and a BayesA model to predict direct genomic values. Accuracies from these cross-validations were 0.27 ± 0.09 and 0.30 ± 0.09 for the K-means and random clustering groups, respectively, compared to respective values of 0.37 ± 0.08 and 0.43 ± 0.08 when using all 41,045 SNPs and BayesB with π = 0.99, or of 0.28 ± 0.07 and 0.40 ± 0.08 with π = 0.999. CONCLUSIONS Bayesian GWAS model parameters can be used to select tag SNPs for a very low-density panel, which will include SNPs that are potentially linked to functional genes. It can be useful for cost-effective genomic selection tools, when one or a few key complex traits are of interest.
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Affiliation(s)
- Bruna P. Sollero
- Embrapa Pecuária Sul, Caixa Postal 242 - BR 153 - Km 633, Bagé, Rio Grande do Sul 96.401-970 Brazil
| | - Vinícius S. Junqueira
- Departamento de Zootecnia, Universidade Federal de Viçosa, Avenida Peter Henry Rolfs, s/n - Campus Universitário, Viçosa, Minas Gerais 36.570-000 Brazil
| | - Cláudia C. G. Gomes
- Embrapa Pecuária Sul, Caixa Postal 242 - BR 153 - Km 633, Bagé, Rio Grande do Sul 96.401-970 Brazil
| | - Alexandre R. Caetano
- Embrapa Recursos Genéticos e Biotecnologia, Parque Estacao Biologica Final Av. W/5 Norte, Brasilia-DF, C.P. 02372, Brasília, Distrito Federal 70770-917 Brazil
| | - Fernando F. Cardoso
- Embrapa Pecuária Sul, Caixa Postal 242 - BR 153 - Km 633, Bagé, Rio Grande do Sul 96.401-970 Brazil
- Universidade Federal de Pelotas, Capão do Leão, Rio Grande do Sul 96.000-010 Brazil
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Lin M, Bachman K, Cheng Z, Daugherty SC, Nagaraj S, Sengamalay N, Ott S, Godinez A, Tallon LJ, Sadzewicz L, Fraser C, Dunning Hotopp JC, Rikihisa Y. Analysis of complete genome sequence and major surface antigens of Neorickettsia helminthoeca, causative agent of salmon poisoning disease. Microb Biotechnol 2017; 10:933-957. [PMID: 28585301 PMCID: PMC5481527 DOI: 10.1111/1751-7915.12731] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 03/09/2017] [Accepted: 04/25/2017] [Indexed: 12/31/2022] Open
Abstract
Neorickettsia helminthoeca, a type species of the genus Neorickettsia, is an endosymbiont of digenetic trematodes of veterinary importance. Upon ingestion of salmonid fish parasitized with infected trematodes, canids develop salmon poisoning disease (SPD), an acute febrile illness that is particularly severe and often fatal in dogs without adequate treatment. We determined and analysed the complete genome sequence of N. helminthoeca: a single small circular chromosome of 884 232 bp encoding 774 potential proteins. N. helminthoeca is unable to synthesize lipopolysaccharides and most amino acids, but is capable of synthesizing vitamins, cofactors, nucleotides and bacterioferritin. N. helminthoeca is, however, distinct from majority of the family Anaplasmataceae to which it belongs, as it encodes nearly all enzymes required for peptidoglycan biosynthesis, suggesting its structural hardiness and inflammatory potential. Using sera from dogs that were experimentally infected by feeding with parasitized fish or naturally infected in southern California, Western blot analysis revealed that among five predicted N. helminthoeca outer membrane proteins, P51 and strain‐variable surface antigen were uniformly recognized. Our finding will help understanding pathogenesis, prevalence of N. helminthoeca infection among trematodes, canids and potentially other animals in nature to develop effective SPD diagnostic and preventive measures. Recent progresses in large‐scale genome sequencing have been uncovering broad distribution of Neorickettsia spp., the comparative genomics will facilitate understanding of biology and the natural history of these elusive environmental bacteria.
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Affiliation(s)
- Mingqun Lin
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH, 43210, USA
| | - Katherine Bachman
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH, 43210, USA
| | - Zhihui Cheng
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH, 43210, USA
| | - Sean C Daugherty
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Sushma Nagaraj
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Naomi Sengamalay
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Sandra Ott
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Al Godinez
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Luke J Tallon
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Lisa Sadzewicz
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Claire Fraser
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA.,Department of Medicine, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Julie C Dunning Hotopp
- Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA.,Department of Microbiology and Immunology, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD, 21201, USA
| | - Yasuko Rikihisa
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH, 43210, USA
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Abstract
Human ehrlichiosis and anaplasmosis are acute febrile tick-borne infectious diseases caused by various members from the genera Ehrlichia and Anaplasma. Ehrlichia chaffeensis is the major etiologic agent of human monocytotropic ehrlichiosis (HME), while Anaplasma phagocytophilum is the major cause of human granulocytic anaplasmosis (HGA). The clinical manifestations of HME and HGA ranges from subclinical to potentially life-threatening diseases associated with multi-organ failure. Macrophages and neutrophils are the major target cells for Ehrlichia and Anaplasma, respectively. The threat to public health is increasing with newly emerging ehrlichial and anaplasma agents, yet vaccines for human ehrlichioses and anaplasmosis are not available, and therapeutic options are limited. This article reviews recent advances in the understanding of HME and HGA.
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Noroy C, Meyer DF. Comparative Genomics of the Zoonotic Pathogen Ehrlichia chaffeensis Reveals Candidate Type IV Effectors and Putative Host Cell Targets. Front Cell Infect Microbiol 2017; 6:204. [PMID: 28180111 PMCID: PMC5263134 DOI: 10.3389/fcimb.2016.00204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 12/21/2016] [Indexed: 12/04/2022] Open
Abstract
During infection, some intracellular pathogenic bacteria use a dedicated multiprotein complex known as the type IV secretion system to deliver type IV effector (T4E) proteins inside the host cell. These T4Es allow the bacteria to evade host defenses and to subvert host cell processes to their own advantage. Ehrlichia chaffeensis is a tick-transmitted obligate intracellular pathogenic bacterium, which causes human monocytic ehrlichiosis. Using comparative whole genome analysis, we identified the relationship between eight available E. chaffeensis genomes isolated from humans and show that these genomes are highly conserved. We identified the candidate core type IV effectome of E. chaffeensis and some conserved intracellular adaptive strategies. We assigned the West Paces strain to genetic group II and predicted the repertoires of T4Es encoded by E. chaffeensis genomes, as well as some putative host cell targets. We demonstrated that predicted T4Es are preferentially distributed in gene sparse regions of the genome. In addition to the identification of the two known type IV effectors of Anaplasmataceae, we identified two novel candidates T4Es, ECHLIB_RS02720 and ECHLIB_RS04640, which are not present in all E. chaffeensis strains and could explain some variations in inter-strain virulence. We also identified another novel candidate T4E, ECHLIB_RS02720, a hypothetical protein exhibiting EPIYA, and NLS domains as well as a classical type IV secretion signal, suggesting an important role inside the host cell. Overall, our results agree with current knowledge of Ehrlichia molecular pathogenesis, and reveal novel candidate T4Es that require experimental validation. This work demonstrates that comparative effectomics enables identification of important host pathways targeted by the bacterial pathogen. Our study, which focuses on the type IV effector repertoires among several strains of E. chaffeensis species, is an original approach and provides rational putative targets for the design of alternative therapeutics against intracellular pathogens. The collection of putative effectors of E. chaffeensis described in our paper could serve as a roadmap for future studies of the function and evolution of effectors.
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Affiliation(s)
- Christophe Noroy
- CIRAD, UMR ASTREGuadeloupe, France; INRA, UMR 1309 ASTREMontpellier, France; Université des AntillesGuadeloupe, France
| | - Damien F Meyer
- CIRAD, UMR ASTREGuadeloupe, France; INRA, UMR 1309 ASTREMontpellier, France
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40
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Genomes of Candidatus Wolbachia bourtzisii wDacA and Candidatus Wolbachia pipientis wDacB from the Cochineal Insect Dactylopius coccus (Hemiptera: Dactylopiidae). G3-GENES GENOMES GENETICS 2016; 6:3343-3349. [PMID: 27543297 PMCID: PMC5068953 DOI: 10.1534/g3.116.031237] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dactylopius species, known as cochineal insects, are the source of the carminic acid dye used worldwide. The presence of two Wolbachia strains in Dactylopius coccus from Mexico was revealed by PCR amplification of wsp and sequencing of 16S rRNA genes. A metagenome analysis recovered the genome sequences of Candidatus Wolbachia bourtzisii wDacA (supergroup A) and Candidatus Wolbachia pipientis wDacB (supergroup B). Genome read coverage, as well as 16S rRNA clone sequencing, revealed that wDacB was more abundant than wDacA. The strains shared similar predicted metabolic capabilities that are common to Wolbachia, including riboflavin, ubiquinone, and heme biosynthesis, but lacked other vitamin and cofactor biosynthesis as well as glycolysis, the oxidative pentose phosphate pathway, and sugar uptake systems. A complete tricarboxylic acid cycle and gluconeogenesis were predicted as well as limited amino acid biosynthesis. Uptake and catabolism of proline were evidenced in Dactylopius Wolbachia strains. Both strains possessed WO-like phage regions and type I and type IV secretion systems. Several efflux systems found suggested the existence of metal toxicity within their host. Besides already described putative virulence factors like ankyrin domain proteins, VlrC homologs, and patatin-like proteins, putative novel virulence factors related to those found in intracellular pathogens like Legionella and Mycobacterium are highlighted for the first time in Wolbachia. Candidate genes identified in other Wolbachia that are likely involved in cytoplasmic incompatibility were found in wDacB but not in wDacA.
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Abstract
The Abelson tyrosine kinases were initially identified as drivers of leukemia in mice and humans. The Abl family kinases Abl1 and Abl2 regulate diverse cellular processes during development and normal homeostasis, and their functions are subverted during inflammation, cancer and other pathologies. Abl kinases can be activated by multiple stimuli leading to cytoskeletal reorganization required for cell morphogenesis, motility, adhesion and polarity. Depending on the cellular context, Abl kinases regulate cell survival and proliferation. Emerging data support important roles for Abl kinases in pathologies linked to inflammation. Among these are neurodegenerative diseases and inflammatory pathologies. Unexpectedly, Abl kinases have also been identified as important players in mammalian host cells during microbial pathogenesis. Thus, the use of Abl kinase inhibitors might prove to be effective in the treatment of pathologies beyond leukemia and solid tumors. In this Cell Science at a Glance article and in the accompanying poster, we highlight the emerging roles of Abl kinases in the regulation of cellular processes in normal cells and diverse pathologies ranging from cancer to microbial pathogenesis.
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Affiliation(s)
- Aaditya Khatri
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jun Wang
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Ann Marie Pendergast
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
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Verhoeve VI, Jirakanwisal K, Utsuki T, Macaluso KR. Differential Rickettsial Transcription in Bloodfeeding and Non-Bloodfeeding Arthropod Hosts. PLoS One 2016; 11:e0163769. [PMID: 27662479 PMCID: PMC5035074 DOI: 10.1371/journal.pone.0163769] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 09/14/2016] [Indexed: 11/21/2022] Open
Abstract
Crucial factors influencing the epidemiology of Rickettsia felis rickettsiosis include pathogenesis and transmission. Detection of R. felis DNA in a number of arthropod species has been reported, with characterized isolates, R. felis strain LSU and strain LSU-Lb, generated from the cat flea, Ctenocephalides felis, and the non-hematophagous booklouse, Liposcelis bostrychophila, respectively. While it is realized that strain influence on host biology varies, the rickettsial response to these distinct host environments remained undefined. To identify a panel of potential rickettsial transmission determinants in the cat flea, the transcriptional profile for these two strains of R. felis were compared in their arthropod hosts using RNAseq. Rickettsial genes with increased transcription in the flea as compared to the booklouse were identified. Genes previously associated with bacterial virulence including LPS biosynthesis, Type IV secretion system, ABC transporters, and a toxin-antitoxin system were selected for further study. Transcription of putative virulence-associated genes was determined in a flea infection bioassay for both strains of R. felis. A host-dependent transcriptional profile during bloodfeeding, specifically, an increased expression of selected transcripts in newly infected cat fleas and flea feces was detected when compared to arthropod cell culture and incubation in vertebrate blood. Together, these studies have identified novel, host-dependent rickettsial factors that likely contribute to successful horizontal transmission by bloodfeeding arthropods.
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Affiliation(s)
- Victoria I. Verhoeve
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
| | - Krit Jirakanwisal
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
| | - Tadanobu Utsuki
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
| | - Kevin R. Macaluso
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
- * E-mail:
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Chimeric Coupling Proteins Mediate Transfer of Heterologous Type IV Effectors through the Escherichia coli pKM101-Encoded Conjugation Machine. J Bacteriol 2016; 198:2701-18. [PMID: 27432829 PMCID: PMC5019051 DOI: 10.1128/jb.00378-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 07/13/2016] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED Bacterial type IV secretion systems (T4SSs) are composed of two major subfamilies, conjugation machines dedicated to DNA transfer and effector translocators for protein transfer. We show here that the Escherichia coli pKM101-encoded conjugation system, coupled with chimeric substrate receptors, can be repurposed for transfer of heterologous effector proteins. The chimeric receptors were composed of the N-terminal transmembrane domain of pKM101-encoded TraJ fused to soluble domains of VirD4 homologs functioning in Agrobacterium tumefaciens, Anaplasma phagocytophilum, or Wolbachia pipientis A chimeric receptor assembled from A. tumefaciens VirD4 (VirD4At) mediated transfer of a MOBQ plasmid (pML122) and A. tumefaciens effector proteins (VirE2, VirE3, and VirF) through the pKM101 transfer channel. Equivalent chimeric receptors assembled from the rickettsial VirD4 homologs similarly supported the transfer of known or candidate effectors from rickettsial species. These findings establish a proof of principle for use of the dedicated pKM101 conjugation channel, coupled with chimeric substrate receptors, to screen for translocation competency of protein effectors from recalcitrant species. Many T4SS receptors carry sequence-variable C-terminal domains (CTDs) with unknown function. While VirD4At and the TraJ/VirD4At chimera with their CTDs deleted supported pML122 transfer at wild-type levels, ΔCTD variants supported transfer of protein substrates at strongly diminished or elevated levels. We were unable to detect binding of VirD4At's CTD to the VirE2 effector, although other VirD4At domains bound this substrate in vitro We propose that CTDs evolved to govern the dynamics of substrate presentation to the T4SS either through transient substrate contacts or by controlling substrate access to other receptor domains. IMPORTANCE Bacterial type IV secretion systems (T4SSs) display striking versatility in their capacity to translocate DNA and protein substrates to prokaryotic and eukaryotic target cells. A hexameric ATPase, the type IV coupling protein (T4CP), functions as a substrate receptor for nearly all T4SSs. Here, we report that chimeric T4CPs mediate transfer of effector proteins through the Escherichia coli pKM101-encoded conjugation system. Studies with these repurposed conjugation systems established a role for acidic C-terminal domains of T4CPs in regulating substrate translocation. Our findings advance a mechanistic understanding of T4CP receptor activity and, further, support a model in which T4SS channels function as passive conduits for any DNA or protein substrates that successfully engage with and pass through the T4CP specificity checkpoint.
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Lind J, Backert S, Hoffmann R, Eichler J, Yamaoka Y, Perez-Perez GI, Torres J, Sticht H, Tegtmeyer N. Systematic analysis of phosphotyrosine antibodies recognizing single phosphorylated EPIYA-motifs in CagA of East Asian-type Helicobacter pylori strains. BMC Microbiol 2016; 16:201. [PMID: 27590005 PMCID: PMC5009636 DOI: 10.1186/s12866-016-0820-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 05/19/2016] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Highly virulent strains of the gastric pathogen Helicobacter pylori encode a type IV secretion system (T4SS) that delivers the effector protein CagA into gastric epithelial cells. Translocated CagA undergoes tyrosine phosphorylation by members of the oncogenic c-Src and c-Abl host kinases at EPIYA-sequence motifs A, B and D in East Asian-type strains. These phosphorylated EPIYA-motifs serve as recognition sites for various SH2-domains containing human proteins, mediating interactions of CagA with host signaling factors to manipulate signal transduction pathways. Recognition of phospho-CagA is mainly based on the use of commercial pan-phosphotyrosine antibodies that were originally designed to detect phosphotyrosines in mammalian proteins. Specific anti-phospho-EPIYA antibodies for each of the three sites in CagA are not forthcoming. RESULTS This study was designed to systematically analyze the detection preferences of each phosphorylated East Asian CagA EPIYA-motif by pan-phosphotyrosine antibodies and to determine a minimal recognition sequence. We synthesized phospho- and non-phosphopeptides derived from each predominant EPIYA-site, and determined the recognition patterns by seven different pan-phosphotyrosine antibodies using Western blotting, and also investigated representative East Asian H. pylori isolates during infection. The results indicate that a total of only 9-11 amino acids containing the phosphorylated East Asian EPIYA-types are required and sufficient to detect the phosphopeptides with high specificity. However, the sequence recognition by the different antibodies was found to bear high variability. From the seven antibodies used, only four recognized all three phosphorylated EPIYA-motifs A, B and D similarly well. Two of the phosphotyrosine antibodies preferentially bound primarily to the phosphorylated motif A and D, while the seventh antibody failed to react with any of the phosphorylated EPIYA-motifs. Control experiments confirmed that none of the antibodies reacted with non-phospho-CagA peptides and in accordance were able to recognize phosphotyrosine proteins in human cells. CONCLUSIONS The results of this study disclose the various binding preferences of commercial anti-phosphotyrosine antibodies for phospho-EPIYA-motifs, and are valuable in the application for further characterization of CagA phosphorylation events during infection with H. pylori and risk prediction for gastric disease development.
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Affiliation(s)
- Judith Lind
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058, Erlangen, Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058, Erlangen, Germany
| | - Rebecca Hoffmann
- Department of Chemistry and Pharmacy, Friedrich Alexander University Erlangen-Nuremberg, Schuhstraße 19, D-91052, Erlangen, Germany
| | - Jutta Eichler
- Department of Chemistry and Pharmacy, Friedrich Alexander University Erlangen-Nuremberg, Schuhstraße 19, D-91052, Erlangen, Germany
| | - Yoshio Yamaoka
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu, Japan
| | - Guillermo I Perez-Perez
- Department of Medicine and Microbiology, New York University, Langone Medical Centre, New York, USA
| | - Javier Torres
- Unidad de Investigación en Enfermedades Infecciosas, Hospital de Pediatría del Instituto Mexicano del Seguro Social, Mexico City, México
| | - Heinrich Sticht
- Bioinformatics, Institute for Biochemistry, Friedrich Alexander University Erlangen-Nuremberg, Fahrstrasse 17, D-91054, Erlangen, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058, Erlangen, Germany.
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Popa CM, Tabuchi M, Valls M. Modification of Bacterial Effector Proteins Inside Eukaryotic Host Cells. Front Cell Infect Microbiol 2016; 6:73. [PMID: 27489796 PMCID: PMC4951486 DOI: 10.3389/fcimb.2016.00073] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 06/27/2016] [Indexed: 12/16/2022] Open
Abstract
Pathogenic bacteria manipulate their hosts by delivering a number of virulence proteins -called effectors- directly into the plant or animal cells. Recent findings have shown that such effectors can suffer covalent modifications inside the eukaryotic cells. Here, we summarize the recent reports where effector modifications by the eukaryotic machinery have been described. We restrict our focus on proteins secreted by the type III or type IV systems, excluding other bacterial toxins. We describe the known examples of effectors whose enzymatic activity is triggered by interaction with plant and animal cell factors, including GTPases, E2-Ubiquitin conjugates, cyclophilin and thioredoxins. We focus on the structural interactions with these factors and their influence on effector function. We also review the described examples of host-mediated post-translational effector modifications which are required for proper subcellular location and function. These host-specific covalent modifications include phosphorylation, ubiquitination, SUMOylation, and lipidations such as prenylation, fatty acylation and phospholipid binding.
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Affiliation(s)
- Crina M Popa
- Department of Genetics, Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB), Universitat de Barcelona Barcelona, Spain
| | - Mitsuaki Tabuchi
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University Kagawa, Japan
| | - Marc Valls
- Department of Genetics, Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB), Universitat de Barcelona Barcelona, Spain
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Abstract
Ehrlichia chaffeensis is an obligatory intracellular and cholesterol-dependent bacterium that has evolved special proteins and functions to proliferate inside leukocytes and cause disease. E. chaffeensis has a multigene family of major outer membrane proteins with porin activity and induces infectious entry using its entry-triggering protein to bind the human cell surface protein DNase X. During intracellular replication, three functional pairs of two-component systems are sequentially expressed to regulate metabolism, aggregation, and the development of stress-resistance traits for transmission. A type IV secretion effector of E. chaffeensis blocks mitochondrion-mediated host cell apoptosis. Several type I secretion proteins are secreted at the Ehrlichia-host interface. E. chaffeensis strains induce strikingly variable inflammation in mice. The central role of MyD88, but not Toll-like receptors, suggests that Ehrlichia species have unique inflammatory molecules. A recent report about transient targeted mutagenesis and random transposon mutagenesis suggests that stable targeted knockouts may become feasible in Ehrlichia.
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Affiliation(s)
- Yasuko Rikihisa
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio 43210;
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47
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Gillespie JJ, Phan IQH, Driscoll TP, Guillotte ML, Lehman SS, Rennoll-Bankert KE, Subramanian S, Beier-Sexton M, Myler PJ, Rahman MS, Azad AF. The Rickettsia type IV secretion system: unrealized complexity mired by gene family expansion. Pathog Dis 2016; 74:ftw058. [PMID: 27307105 PMCID: PMC5505475 DOI: 10.1093/femspd/ftw058] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2016] [Indexed: 12/22/2022] Open
Abstract
Many prokaryotes utilize type IV secretion systems (T4SSs) to translocate substrates (e.g. nucleoprotein, DNA, protein) across the cell envelope, and/or to elaborate surface structures (i.e. pili or adhesins). Among eight distinct T4SS classes, P-T4SSs are typified by the Agrobacterium tumefaciens vir T4SS, which is comprised of 12 scaffold components (VirB1-VirB11, VirD4). While most P-T4SSs include all 12 Vir proteins, some differ from the vir archetype by either containing additional scaffold components not analogous to Vir proteins or lacking one or more of the Vir proteins. In a special case, the Rickettsiales vir homolog (rvh) P-T4SS comprises unprecedented gene family expansion. rvh contains three families of gene duplications (rvhB9, rvhB8, rvhB4): RvhB9,8,4-I are conserved relative to equivalents in other P-T4SSs, while RvhB9,8,4-II have evolved atypical features that deviate substantially from other homologs. Furthermore, rvh contains five VirB6-like genes (rvhB6a-e), which are tandemly arrayed and contain large N- and C-terminal extensions. Our work herein focuses on the complexity underpinned by rvh gene family expansion. Furthermore, we describe an RvhB10 insertion, which occurs in a region that forms the T4SS pore. The significance of these curious properties to rvh structure and function is evaluated, shedding light on a highly complex T4SS.
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Affiliation(s)
- Joseph J Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
| | - Isabelle Q H Phan
- Seattle Structural Genomics Center for Infectious Disease, 307 Westlake Ave North, Seattle, WA 98109, USA Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, WA 98109, USA
| | - Timothy P Driscoll
- Department of Biology, West Virginia University, Life Sciences Building, PO Box 6057, Morgantown, WV 26506-6201, USA
| | - Mark L Guillotte
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
| | - Stephanie S Lehman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
| | - Kristen E Rennoll-Bankert
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
| | - Sandhya Subramanian
- Seattle Structural Genomics Center for Infectious Disease, 307 Westlake Ave North, Seattle, WA 98109, USA Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, WA 98109, USA
| | - Magda Beier-Sexton
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
| | - Peter J Myler
- Seattle Structural Genomics Center for Infectious Disease, 307 Westlake Ave North, Seattle, WA 98109, USA Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, WA 98109, USA
| | - M Sayeedur Rahman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
| | - Abdu F Azad
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
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Mitchell G, Chen C, Portnoy DA. Strategies Used by Bacteria to Grow in Macrophages. Microbiol Spectr 2016; 4:10.1128/microbiolspec.MCHD-0012-2015. [PMID: 27337444 PMCID: PMC4922531 DOI: 10.1128/microbiolspec.mchd-0012-2015] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Indexed: 12/24/2022] Open
Abstract
Intracellular bacteria are often clinically relevant pathogens that infect virtually every cell type found in host organisms. However, myeloid cells, especially macrophages, constitute the primary cells targeted by most species of intracellular bacteria. Paradoxically, macrophages possess an extensive antimicrobial arsenal and are efficient at killing microbes. In addition to their ability to detect and signal the presence of pathogens, macrophages sequester and digest microorganisms using the phagolysosomal and autophagy pathways or, ultimately, eliminate themselves through the induction of programmed cell death. Consequently, intracellular bacteria influence numerous host processes and deploy sophisticated strategies to replicate within these host cells. Although most intracellular bacteria have a unique intracellular life cycle, these pathogens are broadly categorized into intravacuolar and cytosolic bacteria. Following phagocytosis, intravacuolar bacteria reside in the host endomembrane system and, to some extent, are protected from the host cytosolic innate immune defenses. However, the intravacuolar lifestyle requires the generation and maintenance of unique specialized bacteria-containing vacuoles and involves a complex network of host-pathogen interactions. Conversely, cytosolic bacteria escape the phagolysosomal pathway and thrive in the nutrient-rich cytosol despite the presence of host cell-autonomous defenses. The understanding of host-pathogen interactions involved in the pathogenesis of intracellular bacteria will continue to provide mechanistic insights into basic cellular processes and may lead to the discovery of novel therapeutics targeting infectious and inflammatory diseases.
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Affiliation(s)
- Gabriel Mitchell
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Chen Chen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Daniel A. Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- School of Public Health, University of California, Berkeley, Berkeley, CA 94720, USA
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Gonzalez-Rivera C, Bhatty M, Christie PJ. Mechanism and Function of Type IV Secretion During Infection of the Human Host. Microbiol Spectr 2016; 4:10.1128/microbiolspec.VMBF-0024-2015. [PMID: 27337453 PMCID: PMC4920089 DOI: 10.1128/microbiolspec.vmbf-0024-2015] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Indexed: 02/07/2023] Open
Abstract
Bacterial pathogens employ type IV secretion systems (T4SSs) for various purposes to aid in survival and proliferation in eukaryotic hosts. One large T4SS subfamily, the conjugation systems, confers a selective advantage to the invading pathogen in clinical settings through dissemination of antibiotic resistance genes and virulence traits. Besides their intrinsic importance as principle contributors to the emergence of multiply drug-resistant "superbugs," detailed studies of these highly tractable systems have generated important new insights into the mode of action and architectures of paradigmatic T4SSs as a foundation for future efforts aimed at suppressing T4SS machine function. Over the past decade, extensive work on the second large T4SS subfamily, the effector translocators, has identified a myriad of mechanisms employed by pathogens to subvert, subdue, or bypass cellular processes and signaling pathways of the host cell. An overarching theme in the evolution of many effectors is that of molecular mimicry. These effectors carry domains similar to those of eukaryotic proteins and exert their effects through stealthy interdigitation of cellular pathways, often with the outcome not of inducing irreversible cell damage but rather of reversibly modulating cellular functions. This article summarizes the major developments for the actively studied pathogens with an emphasis on the structural and functional diversity of the T4SSs and the emerging common themes surrounding effector function in the human host.
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Affiliation(s)
- Christian Gonzalez-Rivera
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin St, Houston, Texas 77030, Phone: 713-500-5440 (P. J. Christie); 713-500-5441 (C. Gonzalez-Rivera, M. Bhatty)
| | - Minny Bhatty
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin St, Houston, Texas 77030, Phone: 713-500-5440 (P. J. Christie); 713-500-5441 (C. Gonzalez-Rivera, M. Bhatty)
| | - Peter J. Christie
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin St, Houston, Texas 77030, Phone: 713-500-5440 (P. J. Christie); 713-500-5441 (C. Gonzalez-Rivera, M. Bhatty)
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50
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Sun JX, Guo Y, Zhang X, Zhu WC, Chen YT, Hong XY. Effects of host interaction withWolbachiaon cytoplasmic incompatibility in the two-spotted spider miteTetranychus urticae. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12804] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Jian-Xin Sun
- Department of Entomology; Nanjing Agricultural University; No.1, Weigang Nanjing Jiangsu 210095 China
| | - Yan Guo
- Department of Entomology; Nanjing Agricultural University; No.1, Weigang Nanjing Jiangsu 210095 China
| | - Xu Zhang
- Department of Entomology; Nanjing Agricultural University; No.1, Weigang Nanjing Jiangsu 210095 China
| | - Wen-Chao Zhu
- Department of Entomology; Nanjing Agricultural University; No.1, Weigang Nanjing Jiangsu 210095 China
| | - Ya-Ting Chen
- Department of Entomology; Nanjing Agricultural University; No.1, Weigang Nanjing Jiangsu 210095 China
| | - Xiao-Yue Hong
- Department of Entomology; Nanjing Agricultural University; No.1, Weigang Nanjing Jiangsu 210095 China
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