1
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Sit B, Lamason RL. Pathogenic Rickettsia spp. as emerging models for bacterial biology. J Bacteriol 2024; 206:e0040423. [PMID: 38315013 PMCID: PMC10883807 DOI: 10.1128/jb.00404-23] [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] [Indexed: 02/07/2024] Open
Abstract
Our understanding of free-living bacterial models like Escherichia coli far outpaces that of obligate intracellular bacteria, which cannot be cultured axenically. All obligate intracellular bacteria are host-associated, and many cause serious human diseases. Their constant exposure to the distinct biochemical niche of the host has driven the evolution of numerous specialized bacteriological and genetic adaptations, as well as innovative molecular mechanisms of infection. Here, we review the history and use of pathogenic Rickettsia species, which cause an array of vector-borne vascular illnesses, as model systems to probe microbial biology. Although many challenges remain in our studies of these organisms, the rich pathogenic and biological diversity of Rickettsia spp. constitutes a unique backdrop to investigate how microbes survive and thrive in host and vector cells. We take a bacterial-focused perspective and highlight emerging insights that relate to new host-pathogen interactions, bacterial physiology, and evolution. The transformation of Rickettsia spp. from pathogens to models demonstrates how recalcitrant microbes may be leveraged in the lab to tap unmined bacterial diversity for new discoveries. Rickettsia spp. hold great promise as model systems not only to understand other obligate intracellular pathogens but also to discover new biology across and beyond bacteria.
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Affiliation(s)
- Brandon Sit
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Rebecca L. Lamason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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2
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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: 2] [Impact Index Per Article: 2.0] [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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3
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Narra HP, Alsing J, Sahni A, Montini M, Zafar Y, Sahni SK. A Small Non-Coding RNA Mediates Transcript Stability and Expression of Cytochrome bd Ubiquinol Oxidase Subunit I in Rickettsia conorii. Int J Mol Sci 2023; 24:4008. [PMID: 36835430 PMCID: PMC9960880 DOI: 10.3390/ijms24044008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/08/2023] [Accepted: 02/11/2023] [Indexed: 02/19/2023] Open
Abstract
Small regulatory RNAs (sRNAs) are now widely recognized for their role in the post-transcriptional regulation of bacterial virulence and growth. We have previously demonstrated the biogenesis and differential expression of several sRNAs in Rickettsia conorii during interactions with the human host and arthropod vector, as well as the in vitro binding of Rickettsia conorii sRNA Rc_sR42 to bicistronic cytochrome bd ubiquinol oxidase subunits I and II (cydAB) mRNA. However, the mechanism of regulation and the effect of sRNA binding on the stability of the cydAB bicistronic transcript and the expression of the cydA and cydB genes are still unknown. In this study, we determined the expression dynamics of Rc_sR42 and its cognate target genes, cydA and cydB, in mouse lung and brain tissues during R. conorii infection in vivo and employed fluorescent and reporter assays to decode the role of sRNA in regulating cognate gene transcripts. Quantitative RT-PCR revealed significant changes in the expression of sRNA and its cognate target gene transcripts during R. conorii infection in vivo, and a greater abundance of these transcripts was observed in the lungs compared to brain tissue. Interestingly, while Rc_sR42 and cydA exhibited similar patterns of change in their expression, indicating the influence of sRNA on the mRNA target, the expression of cydB was independent of sRNA expression. Further, we constructed reporter plasmids of sRNA and cydAB bicistronic mRNA to decipher the role of sRNA on CydA and CydB expression. We observed increased expression of CydA in the presence of sRNA but detected no change in CydB expression in the presence or absence of sRNA. In sum, our results demonstrate that the binding of Rc_sR42 is required for the regulation of cydA but not cydB. Further studies on understanding the influence of this interaction on the mammalian host and tick vector during R. conorii infection are in progress.
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Affiliation(s)
- Hema P. Narra
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | | | | | | | | | - Sanjeev K. Sahni
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
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4
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Lemenze A, Mittal N, Perryman AL, Daher SS, Ekins S, Occi J, Ahn YM, Wang X, Russo R, Patel JS, Daugherty RM, Wood DO, Connell N, Freundlich JS. Rickettsia Aglow: A Fluorescence Assay and Machine Learning Model to Identify Inhibitors of Intracellular Infection. ACS Infect Dis 2022; 8:1280-1290. [PMID: 35748568 PMCID: PMC9912140 DOI: 10.1021/acsinfecdis.2c00014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Rickettsia is a genus of Gram-negative bacteria that has for centuries caused large-scale morbidity and mortality. In recent years, the resurgence of rickettsial diseases as a major cause of pyrexias of unknown origin, bioterrorism concerns, vector movement, and concerns over drug resistance is driving a need to identify novel treatments for these obligate intracellular bacteria. Utilizing an uvGFP plasmid reporter, we developed a screen for identifying anti-rickettsial small molecule inhibitors using Rickettsia canadensis as a model organism. The screening data were utilized to train a Bayesian model to predict growth inhibition in this assay. This two-pronged methodology identified anti-rickettsial compounds, including duartin and JSF-3204 as highly specific, efficacious, and noncytotoxic compounds. Both molecules exhibited in vitro growth inhibition of R. prowazekii, the causative agent of epidemic typhus. These small molecules and the workflow, featuring a high-throughput phenotypic screen for growth inhibitors of intracellular Rickettsia spp. and machine learning models for the prediction of growth inhibition of an obligate intracellular Gram-negative bacterium, should prove useful in the search for new therapeutic strategies to treat infections from Rickettsia spp. and other obligate intracellular bacteria.
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Affiliation(s)
- Alexander Lemenze
- Department of Medicine, and the Ruy V. Lourenco Center for the Study of Emerging and Reemerging Pathogens, Rutgers University - New Jersey Medical School, Newark, New Jersey 07103, United States; Present Address: Department of Pathology, Immunology, and Laboratory Medicine, Rutgers University - New Jersey Medical School, Cancer Center Building, 205 South Orange Avenue, Newark, New Jersey 07103, United States
| | - Nisha Mittal
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University - New Jersey Medical School, Newark, New Jersey 07103, United States; Present Address: Bristol Myers Squibb, 1 Squibb Drive, Building 85 Room A-WS216D, New Brunswick, New Jersey 08901, United States
| | - Alexander L. Perryman
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University - New Jersey Medical School, Newark, New Jersey 07103, United States; Present Address: Repare Therapeutics, 7171 Rue Frederick-Banting, Montreal, Quebec H4S 1Z9, Canada
| | - Samer S. Daher
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University - New Jersey Medical School, Newark, New Jersey 07103, United States; Present Address: Ambrx, 10975 N. Torrey Pines Road, La Jolla, California 92037, United States
| | - Sean Ekins
- Collaborations in Chemistry, Fuquay-Varina, North Carolina 27526, United States; Present Address: Collaborations Pharmaceuticals, Inc., Main Campus Drive, Lab 3510 Raleigh, North Carolina 27606, United States
| | - James Occi
- Department of Medicine, and the Ruy V. Lourenco Center for the Study of Emerging and Reemerging Pathogens, Rutgers University - New Jersey Medical School, Newark, New Jersey 07103, United States; Present Address: Center for Vector Biology, Department of Entomology, Rutgers University, 180 Jones Avenue, New Brunswick, New Jersey 08901, United States
| | - Yong-Mo Ahn
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University - New Jersey Medical School, Newark, New Jersey 07103, United States
| | - Xin Wang
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University - New Jersey Medical School, Newark, New Jersey 07103, United States; Present Address: Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, United States
| | - Riccardo Russo
- Department of Medicine, and the Ruy V. Lourenco Center for the Study of Emerging and Reemerging Pathogens, Rutgers University - New Jersey Medical School, Newark, New Jersey 07103, United States
| | - Jimmy S. Patel
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University - New Jersey Medical School, Newark, New Jersey 07103, United States; Present Address: Department of Radiation Oncology, Winship Cancer Institute of Emory University, 1365-A Clifton Road NE, Atlanta, Georgia 30322, United States
| | - Robin M. Daugherty
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, United States
| | - David O. Wood
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, United States
| | - Nancy Connell
- Department of Medicine, and the Ruy V. Lourenco Center for the Study of Emerging and Reemerging Pathogens, Rutgers University - New Jersey Medical School, Newark, New Jersey 07103, United States; Present Address: U.S. National Academies of Science, Engineering and Medicine, 500 5th Street NW, Washington, District of Columbia 20002, United States
| | - Joel S. Freundlich
- Department of Medicine, and the Ruy V. Lourenco Center for the Study of Emerging and Reemerging Pathogens and Department of Pharmacology, Physiology, and Neuroscience, Rutgers University - New Jersey Medical School, Newark, New Jersey 07103, United States
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5
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Genomic evolution and adaptation of arthropod-associated Rickettsia. Sci Rep 2022; 12:3807. [PMID: 35264613 PMCID: PMC8907221 DOI: 10.1038/s41598-022-07725-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 02/16/2022] [Indexed: 11/17/2022] Open
Abstract
Rickettsia species are endosymbionts hosted by arthropods and are known to cause mild to fatal diseases in humans. Here, we analyse the evolution and diversity of 34 Rickettsia species using a pangenomic meta-analysis (80 genomes/41 plasmids). Phylogenomic trees showed that Rickettsia spp. diverged into two Spotted Fever groups, a Typhus group, a Canadensis group and a Bellii group, and may have inherited their plasmids from an ancestral plasmid that persisted in some strains or may have been lost by others. The results suggested that the ancestors of Rickettsia spp. might have infected Acari and/or Insecta and probably diverged by persisting inside and/or switching hosts. Pangenomic analysis revealed that the Rickettsia genus evolved through a strong interplay between genome degradation/reduction and/or expansion leading to possible distinct adaptive trajectories. The genus mainly shared evolutionary relationships with α-proteobacteria, and also with γ/β/δ-proteobacteria, cytophagia, actinobacteria, cyanobacteria, chlamydiia and viruses, suggesting lateral exchanges of several critical genes. These evolutionary processes have probably been orchestrated by an abundance of mobile genetic elements, especially in the Spotted Fever and Bellii groups. In this study, we provided a global evolutionary genomic view of the intracellular Rickettsia that may help our understanding of their diversity, adaptation and fitness.
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Salata C, Moutailler S, Attoui H, Zweygarth E, Decker L, Bell-Sakyi L. How relevant are in vitro culture models for study of tick-pathogen interactions? Pathog Glob Health 2021; 115:437-455. [PMID: 34190676 PMCID: PMC8635668 DOI: 10.1080/20477724.2021.1944539] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Although tick-borne infectious diseases threaten human and animal health worldwide, with constantly increasing incidence, little knowledge is available regarding vector-pathogen interactions and pathogen transmission. In vivo laboratory study of these subjects using live, intact ticks is expensive, labor-intensive, and challenging from the points of view of biosafety and ethics. Several in vitro models have been developed, including over 70 continuous cell lines derived from multiple tick species and a variety of tick organ culture systems, facilitating many research activities. However, some limitations have to be considered in the translation of the results from the in vitro environment to the in vivo situation of live, intact ticks, and vertebrate hosts. In this review, we describe the available in vitro models and selected results from their application to the study of tick-borne viruses, bacteria, and protozoa, where possible comparing these results to studies in live, intact ticks. Finally, we highlight the strengths and weaknesses of in vitro tick culture models and their essential role in tick-borne pathogen research.
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Affiliation(s)
- Cristiano Salata
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Sara Moutailler
- Laboratoire De Santé Animale, Anses, INRAE, Ecole Nationale Vétérinaire d’Alfort, UMR BIPAR, Maisons-Alfort, France
| | - Houssam Attoui
- Department of Animal Health, UMR1161 Virologie, INRAE, Ecole Nationale Vétérinaire d’Alfort, ANSES, Université Paris-Est, Maisons-Alfort, France
| | - Erich Zweygarth
- The Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa
| | - Lygia Decker
- Department of Preventive Veterinary Medicine, School of Veterinary Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Lesley Bell-Sakyi
- Department of Infection Biology and Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
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7
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Rauch J, Barton J, Kwiatkowski M, Wunderlich M, Steffen P, Moderzynski K, Papp S, Höhn K, Schwanke H, Witt S, Richardt U, Mehlhoop U, Schlüter H, Pianka V, Fleischer B, Tappe D, Osterloh A. GroEL is an immunodominant surface-exposed antigen of Rickettsia typhi. PLoS One 2021; 16:e0253084. [PMID: 34111210 PMCID: PMC8191997 DOI: 10.1371/journal.pone.0253084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/28/2021] [Indexed: 11/26/2022] Open
Abstract
Rickettsioses are neglected and emerging potentially fatal febrile diseases that are caused by obligate intracellular bacteria, rickettsiae. Rickettsia (R.) typhi and R. prowazekii constitute the typhus group (TG) of rickettsiae and are the causative agents of endemic and epidemic typhus, respectively. We recently generated a monoclonal antibody (BNI52) against R. typhi. Characterization of BNI52 revealed that it specifically recognizes TG rickettsiae but not the members of the spotted fever group (SFG) rickettsiae. We further show that BNI52 binds to protein fragments of ±30 kDa that are exposed on the bacterial surface and also present in the periplasmic space. These protein fragments apparently derive from the cytosolic GroEL protein of R. typhi and are also recognized by antibodies in the sera from patients and infected mice. Furthermore, BNI52 opsonizes the bacteria for the uptake by antigen presenting cells (APC), indicating a contribution of GroEL-specific antibodies to protective immunity. Finally, it is interesting that the GroEL protein belongs to 32 proteins that are differentially downregulated by R. typhi after passage through immunodeficient BALB/c CB17 SCID mice. This could be a hint that the rickettsia GroEL protein may have immunomodulatory properties as shown for the homologous protein from several other bacteria, too. Overall, the results of this study provide evidence that GroEL represents an immunodominant antigen of TG rickettsiae that is recognized by the humoral immune response against these pathogens and that may be interesting as a vaccine candidate. Apart from that, the BNI52 antibody represents a new tool for specific detection of TG rickettsiae in various diagnostic and experimental setups.
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Affiliation(s)
- Jessica Rauch
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Jessica Barton
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Malte Wunderlich
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Pascal Steffen
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Stefanie Papp
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Katharina Höhn
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Hella Schwanke
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Susanne Witt
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ulricke Richardt
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ute Mehlhoop
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Verena Pianka
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Dennis Tappe
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Anke Osterloh
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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8
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Cutler SJ, Vayssier-Taussat M, Estrada-Peña A, Potkonjak A, Mihalca AD, Zeller H. Tick-borne diseases and co-infection: Current considerations. Ticks Tick Borne Dis 2020; 12:101607. [PMID: 33220628 DOI: 10.1016/j.ttbdis.2020.101607] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 10/10/2020] [Accepted: 11/05/2020] [Indexed: 02/08/2023]
Abstract
Over recent years, a multitude of pathogens have been reported to be tick-borne. Given this, it is unsurprising that these might co-exist within the same tick, however our understanding of the interactions of these agents both within the tick and vertebrate host remains poorly defined. Despite the rich diversity of ticks, relatively few regularly feed on humans, 12 belonging to argasid and 20 ixodid species, and literature on co-infection is only available for a few of these species. The interplay of various pathogen combinations upon the vertebrate host and tick vector represents a current knowledge gap. The impact of co-infection in humans further extends into diagnostic challenges arising when multiple pathogens are encountered and we have little current data upon which to make therapeutic recommendations for those with multiple infections. Despite these short-comings, there is now increasing recognition of co-infections and current research efforts are providing valuable insights into dynamics of pathogen interactions whether they facilitate or antagonise each other. Much of this existing data is focussed upon simultaneous infection, however the consequences of sequential infection also need to be addressed. To this end, it is timely to review current understanding and highlight those areas still to address.
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Affiliation(s)
- Sally J Cutler
- School of Health, Sport & Bioscience, University of East London, London, E15 4LZ, UK.
| | | | - Agustín Estrada-Peña
- Department of Animal Health, Faculty of Veterinary Medicine, University of Zaragoza, Spain
| | - Aleksandar Potkonjak
- Department of Veterinary Medicine, Faculty of Agriculture, University of Novi Sad, Serbia
| | - Andrei D Mihalca
- Department of Parasitology and Parasitic Diseases, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Romania
| | - Hervé Zeller
- European Centre for Disease Prevention and Control, Solna, Sweden
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9
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Bensaoud C, Martins LA, Aounallah H, Hackenberg M, Kotsyfakis M. Emerging roles of non-coding RNAs in vector-borne infections. J Cell Sci 2020; 134:134/5/jcs246744. [PMID: 33154170 DOI: 10.1242/jcs.246744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Non-coding RNAs (ncRNAs) are nucleotide sequences that are known to assume regulatory roles previously thought to be reserved for proteins. Their functions include the regulation of protein activity and localization and the organization of subcellular structures. Sequencing studies have now identified thousands of ncRNAs encoded within the prokaryotic and eukaryotic genomes, leading to advances in several fields including parasitology. ncRNAs play major roles in several aspects of vector-host-pathogen interactions. Arthropod vector ncRNAs are secreted through extracellular vesicles into vertebrate hosts to counteract host defense systems and ensure arthropod survival. Conversely, hosts can use specific ncRNAs as one of several strategies to overcome arthropod vector invasion. In addition, pathogens transmitted through vector saliva into vertebrate hosts also possess ncRNAs thought to contribute to their pathogenicity. Recent studies have addressed ncRNAs in vectors or vertebrate hosts, with relatively few studies investigating the role of ncRNAs derived from pathogens and their involvement in establishing infections, especially in the context of vector-borne diseases. This Review summarizes recent data focusing on pathogen-derived ncRNAs and their role in modulating the cellular responses that favor pathogen survival in the vertebrate host and the arthropod vector, as well as host ncRNAs that interact with vector-borne pathogens.
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Affiliation(s)
- Chaima Bensaoud
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005, Ceske Budejovice (Budweis), Czechia
| | - Larissa Almeida Martins
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005, Ceske Budejovice (Budweis), Czechia
| | - Hajer Aounallah
- Université de Tunis El Manar, Institut Pasteur de Tunis, LR11IPT03, Service d'entomologie médicale, 1002, Tunis, Tunisie.,Innovation and Development Laboratory, Innovation and Development Center, Instituto Butantan, São Paulo 05503-900, Brazil
| | - Michael Hackenberg
- Dpto. de Genética, Facultad de Ciencias, Universidad de Granada, Campus de Fuentenueva s/n, 18071, Granada, Spain.,Lab. de Bioinformática, Centro de Investigación Biomédica, PTS, Instituto de Biotecnología, Avda. del Conocimiento s/n, Granada 18100, Spain
| | - Michail Kotsyfakis
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005, Ceske Budejovice (Budweis), Czechia
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10
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Narra HP, Sahni A, Alsing J, Schroeder CLC, Golovko G, Nia AM, Fofanov Y, Khanipov K, Sahni SK. Comparative transcriptomic analysis of Rickettsia conorii during in vitro infection of human and tick host cells. BMC Genomics 2020; 21:665. [PMID: 32977742 PMCID: PMC7519539 DOI: 10.1186/s12864-020-07077-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 09/17/2020] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Pathogenic Rickettsia species belonging to the spotted fever group are arthropod-borne, obligate intracellular bacteria which exhibit preferential tropism for host microvascular endothelium in the mammalian hosts, resulting in disease manifestations attributed primarily to endothelial damage or dysfunction. Although rickettsiae are known to undergo evolution through genomic reduction, the mechanisms by which these pathogens regulate their transcriptome to ensure survival in tick vectors and maintenance by transovarial/transstadial transmission, in contrast to their ability to cause debilitating infections in human hosts remain unknown. In this study, we compare the expression profiles of rickettsial sRNAome/transcriptome and determine the transcriptional start sites (TSSs) of R. conorii transcripts during in vitro infection of human and tick host cells. RESULTS We performed deep sequencing on total RNA from Amblyomma americanum AAE2 cells and human microvascular endothelial cells (HMECs) infected with R. conorii. Strand-specific RNA sequencing of R. conorii transcripts revealed the expression 32 small RNAs (Rc_sR's), which were preferentially expressed above the limit of detection during tick cell infection, and confirmed the expression of Rc_sR61, sR71, and sR74 by quantitative RT-PCR. Intriguingly, a total of 305 and 132 R. conorii coding genes were differentially upregulated (> 2-fold) in AAE2 cells and HMECs, respectively. Further, enrichment for primary transcripts by treatment with Terminator 5'-Phosphate-dependent Exonuclease resulted in the identification of 3903 and 2555 transcription start sites (TSSs), including 214 and 181 primary TSSs in R. conorii during the infection to tick and human host cells, respectively. Seventy-five coding genes exhibited different TSSs depending on the host environment. Finally, we also observed differential expression of 6S RNA during host-pathogen and vector-pathogen interactions in vitro, implicating an important role for this noncoding RNA in the regulation of rickettsial transcriptome depending on the supportive host niche. CONCLUSIONS In sum, the findings of this study authenticate the presence of novel Rc_sR's in R. conorii, reveal the first evidence for differential expression of coding transcripts and utilization of alternate transcriptional start sites depending on the host niche, and implicate a role for 6S RNA in the regulation of coding transcriptome during tripartite host-pathogen-vector interactions.
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Affiliation(s)
- Hema P Narra
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA.
| | - Abha Sahni
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Jessica Alsing
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Casey L C Schroeder
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - George Golovko
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Anna M Nia
- Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Yuriy Fofanov
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Kamil Khanipov
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Sanjeev K Sahni
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA.
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11
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Narra HP, Sahni A, Walker DH, Sahni SK. Recent research milestones in the pathogenesis of human rickettsioses and opportunities ahead. Future Microbiol 2020; 15:753-765. [PMID: 32691620 DOI: 10.2217/fmb-2019-0266] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Infections caused by pathogenic Rickettsia species continue to scourge human health across the globe. From the point of entry at the site of transmission by arthropod vectors, hematogenous dissemination of rickettsiae occurs to diverse host tissues leading to 'rickettsial vasculitis' as the salient feature of pathogenesis. This perspective article accentuates recent breakthrough developments in the context of host-pathogen-vector interactions during rickettsial infections. The subtopics include potential exploitation of circulating macrophages for spread, identification of new entry mechanisms and regulators of actin-based motility, appreciation of metabolites acquired from and effectors delivered into the host, importance of the toxin-antitoxin module in host-cell interactions, effects of the vector microbiome on rickettsial transmission, and niche-specific riboregulation and adaptation. Further research on these aspects will advance our understanding of the biology of rickettsiae as intracellular pathogens and should enable design and development of new approaches to counter rickettsioses in humans and other hosts.
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Affiliation(s)
- Hema P Narra
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Abha Sahni
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - David H Walker
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Sanjeev K Sahni
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
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12
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López-Valencia D, Medina-Ortega ÁP, Hoyos-Samboní DF, Salguero C, Vásquez-Arteaga LR. Pediculosis capitis y transmisión potencial de enfermedades infecciosas reemergentes en Colombia. Revisión de la literatura. REVISTA DE LA FACULTAD DE MEDICINA 2020. [DOI: 10.15446/revfacmed.v68n2.76604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Introducción. La infestación por piojos de la cabeza en humanos (Pediculus humanus capitis) se conoce como pediculosis capitis. Estos parásitos pueden ser vectores de enfermedades infecciosas con potencial reemergente.Objetivos. Revisar la literatura actual sobre las enfermedades infecciosas transmitidas por piojos de la cabeza y realizar una breve descripción de sus manifestaciones clínicas.Materiales y métodos. Se realizó una revisión de la literatura en PubMed, ScienceDirect, SciELO y Redalyc mediante la siguiente estrategia de búsqueda: años de publicación: 1938 a 2019; idioma: inglés y español; términos de búsqueda: “Pediculus”, “lice infestations”, “bacteria”, “emerging communicable diseases”, “Rickettsia”, “Bartonella”, “Borrelia”, “Acinetobacter”, “Yersinia“, and “Colombia”, y sus equivalentes en español.Resultados. De los 110 artículos incluidos, la mayoría correspondió a investigaciones originales (48.2%). A nivel mundial, numerosos estudios han reportado la transmisión de Rickettsia prowazekii, Bartonella quintana, Borrelia recurrentis, Staphylococcus aureus, Acinetobacter baumannii y Yersinia pestis, entre otras bacterias, por los piojos de la cabeza y del cuerpo en humanos.Conclusiones. Aunque las enfermedades infecciosas transmitidas por piojos de la cabeza son raras, guardan potencial reemergente en poblaciones afectadas por migraciones humanas, crisis sociopolíticas, indigencia e inmunosupresión. En Colombia no se han realizado investigaciones sobre la transmisión de estas enfermedades por Pediculus spp., por lo que se sugiere que en estudios futuros se determine la prevalencia y los aspectos epidemiológicos de las enfermedades transmitidas por piojos de la cabeza en población colombiana.
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13
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Thairu MW, Hansen AK. It's a small, small world: unravelling the role and evolution of small RNAs in organelle and endosymbiont genomes. FEMS Microbiol Lett 2019; 366:5371121. [PMID: 30844054 DOI: 10.1093/femsle/fnz049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 03/05/2019] [Indexed: 12/19/2022] Open
Abstract
Organelles and host-restricted bacterial symbionts are characterized by having highly reduced genomes that lack many key regulatory genes and elements. Thus, it has been hypothesized that the eukaryotic nuclear genome is primarily responsible for regulating these symbioses. However, with the discovery of organelle- and symbiont-expressed small RNAs (sRNAs) there is emerging evidence that these sRNAs may play a role in gene regulation as well. Here, we compare the diversity of organelle and bacterial symbiont sRNAs recently identified using genome-enabled '-omic' technologies and discuss their potential role in gene regulation. We also discuss how the genome architecture of small genomes may influence the evolution of these sRNAs and their potential function. Additionally, these new studies suggest that some sRNAs are conserved within organelle and symbiont taxa and respond to changes in the environment and/or their hosts. In summary, these results suggest that organelle and symbiont sRNAs may play a role in gene regulation in addition to nuclear-encoded host mechanisms.
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Affiliation(s)
- Margaret W Thairu
- Department of Entomology, University of California, Riverside, Riverside, CA, USA
| | - Allison K Hansen
- Department of Entomology, University of California, Riverside, Riverside, CA, USA
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14
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Thairu MW, Hansen AK. Changes in Aphid Host Plant Diet Influence the Small-RNA Expression Profiles of Its Obligate Nutritional Symbiont, Buchnera. mBio 2019; 10:e01733-19. [PMID: 31744912 PMCID: PMC6867890 DOI: 10.1128/mbio.01733-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 10/08/2019] [Indexed: 12/31/2022] Open
Abstract
Plants are a difficult food resource to use, and herbivorous insects have evolved a variety of mechanisms that allow them to fully exploit this poor nutritional resource. One such mechanism is the maintenance of bacterial symbionts that aid in host plant feeding and development. The majority of these intracellular symbionts have highly eroded genomes that lack many key regulatory genes; consequently, it is unclear if these symbionts can respond to changes in the insect's diet to facilitate host plant use. There is emerging evidence that symbionts with highly eroded genomes express small RNAs (sRNAs), some of which potentially regulate gene expression. In this study, we sought to determine if the reduced genome of the nutritional symbiont (Buchnera) in the pea aphid responds to changes in the aphid's host plant diet. Using transcriptome sequencing (RNA-seq), Buchnera sRNA expression profiles were characterized within two Buchnera life stages when pea aphids fed on either alfalfa or fava bean. Overall, this study demonstrates that Buchnera sRNA expression changes not only with life stage but also with changes in aphid host plant diet. Of the 321 sRNAs characterized in this study, 47% were previously identified and 22% showed evidence of conservation in two or more Buchnera taxa. Functionally, 13 differentially expressed sRNAs were predicted to target genes related to pathways involved in essential amino acid biosynthesis. Overall, results from this study reveal that host plant diet influences the expression of conserved and lineage-specific sRNAs in Buchnera and that these sRNAs display distinct host plant-specific expression profiles among biological replicates.IMPORTANCE In general, the genomes of intracellular bacterial symbionts are reduced compared to those of free-living relatives and lack many key regulatory genes. Many of these reduced genomes belong to obligate mutualists of insects that feed on a diet that is deficient in essential nutrients, such as essential amino acids. It is unclear if these symbionts respond with their host to changes in insect diet, because of their reduced regulatory capacity. Emerging evidence suggests that these symbionts express small RNAs (sRNAs) that regulate gene expression at the posttranscriptional level. Therefore, in this study, we sought to determine if the reduced genome of the nutritional symbiont Buchnera in the pea aphid responds to changes in the aphid's host plant diet. This study demonstrates for the first time that Buchnera sRNAs, some conserved in two or more Buchnera lineages, are differentially expressed when aphids feed on different plant species and potentially target genes within essential amino acid biosynthesis pathways.
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Affiliation(s)
- Margaret W Thairu
- Department of Entomology, University of California, Riverside, Riverside, California, USA
- Department of Bacteriology, University of Wisconsin, Madison, Madison, Wisconsin, USA
| | - Allison K Hansen
- Department of Entomology, University of California, Riverside, Riverside, California, USA
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15
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González Plaza JJ. Small RNAs in cell-to-cell communications during bacterial infection. FEMS Microbiol Lett 2019; 365:4830097. [PMID: 29390095 DOI: 10.1093/femsle/fny024] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 01/25/2018] [Indexed: 01/18/2023] Open
Abstract
Intercellular communication is a widespread phenomenon in all domains of life. Bacteria have developed many ways of communicating with one another and with other species, either prokaryotic or eukaryotic. RNA has been a key molecule since the beginning of life on Earth, and is one of the carriers of information. Given the current antibiotic crisis, understanding the way in which pathogens communicate can lead towards improved ways to control infections when antimicrobial therapy is not possible. Different subspecies of RNA, non-coding, and of small size, designated here as ncRNAs, have been in recent years the subject of a great research effort, and results have contributed to a growing field of knowledge. This review focuses on four different aspects of ncRNA involvement in cell-to-cell communications during bacterial infections: pathogen recognition by the host, alteration of host microRNA profiles, production of domestic and secreted forms of ncRNAs and subversion of the host responses. The current review article focuses on the most recent discoveries in the field and gives an integrative idea based on the discussed studies.
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Affiliation(s)
- Juan José González Plaza
- Research Department, University Hospital for Infectious Diseases "Dr. Fran Mihaljevic", Zagreb, Croatia
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16
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Sahni A, Fang R, Sahni SK, Walker DH. Pathogenesis of Rickettsial Diseases: Pathogenic and Immune Mechanisms of an Endotheliotropic Infection. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2018; 14:127-152. [PMID: 30148688 DOI: 10.1146/annurev-pathmechdis-012418-012800] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Obligately intracytosolic rickettsiae that cycle between arthropod and vertebrate hosts cause human diseases with a spectrum of severity, primarily by targeting microvascular endothelial cells, resulting in endothelial dysfunction. Endothelial cells and mononuclear phagocytes have important roles in the intracellular killing of rickettsiae upon activation by the effector molecules of innate and adaptive immunity. In overwhelming infection, immunosuppressive effects contribute to the severity of illness. Rickettsia-host cell interactions involve host cell receptors for rickettsial ligands that mediate cell adhesion and, in some instances, trigger induced phagocytosis. Rickettsiae interact with host cell actin to effect both cellular entry and intracellular actin-based mobility. The interaction of rickettsiae with the host cell also involves rickettsial evasion of host defense mechanisms and exploitation of the intracellular environment. Signal transduction events exemplify these effects. An intriguing frontier is the array of rickettsial noncoding RNA molecules and their potential effects on the pathogenesis and transmission of rickettsial diseases.
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Affiliation(s)
- Abha Sahni
- The University of Texas Medical Branch at Galveston, Galveston, Texas 77555-0609, USA; , , ,
| | - Rong Fang
- The University of Texas Medical Branch at Galveston, Galveston, Texas 77555-0609, USA; , , ,
| | - Sanjeev K Sahni
- The University of Texas Medical Branch at Galveston, Galveston, Texas 77555-0609, USA; , , ,
| | - David H Walker
- The University of Texas Medical Branch at Galveston, Galveston, Texas 77555-0609, USA; , , ,
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17
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Quiroz-Castañeda RE, Cobaxin-Cárdenas M, Cuervo-Soto LI. Exploring the diversity, infectivity and metabolomic landscape of Rickettsial infections for developing novel therapeutic intervention strategies. Cytokine 2018; 112:63-74. [PMID: 30072088 DOI: 10.1016/j.cyto.2018.07.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 07/09/2018] [Accepted: 07/17/2018] [Indexed: 12/25/2022]
Abstract
Rickettsioses are zoonotic infections caused by obligate intracellular bacteria of the genera Rickettsia that affect human health; sometimes humans being considered as accidental hosts. At a molecular level, the rickettsiae infection triggers molecular signaling leading to the secretion of proinflammatory cytokines. These cytokines direct the immune response to the host cell damage and pathogen removal. In this review, we present metabolic aspects of the host cell in the presence of rickettsiae and how this presence triggers an inflammatory response to cope with the pathogen. We also reviewed the secretion of cytokines that modulates host cell response at immune and metabolic levels.
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Affiliation(s)
- Rosa Estela Quiroz-Castañeda
- Unidad de Anaplasmosis, Centro Nacional de Investigación Disciplinaria en Parasitología Veterinaria, (CENID-PAVET, INIFAP), Carretera Federal Cuernavaca Cuautla 8534, Progreso, 62574 Jiutepec, Morelos, Mexico.
| | - Mayra Cobaxin-Cárdenas
- Unidad de Anaplasmosis, Centro Nacional de Investigación Disciplinaria en Parasitología Veterinaria, (CENID-PAVET, INIFAP), Carretera Federal Cuernavaca Cuautla 8534, Progreso, 62574 Jiutepec, Morelos, Mexico.
| | - Laura Inés Cuervo-Soto
- Facultad de Ciencias, Departamento de Biología, Universidad Antonio Nariño, Sede Circunvalar Carrera 3 Este, No. 47 A15, Bogotá, Colombia
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18
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Antunes S, Couto J, Ferrolho J, Rodrigues F, Nobre J, Santos AS, Santos-Silva MM, de la Fuente J, Domingos A. Rhipicephalus bursa Sialotranscriptomic Response to Blood Feeding and Babesia ovis Infection: Identification of Candidate Protective Antigens. Front Cell Infect Microbiol 2018; 8:116. [PMID: 29780749 PMCID: PMC5945973 DOI: 10.3389/fcimb.2018.00116] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 03/23/2018] [Indexed: 02/03/2023] Open
Abstract
Ticks are among the most prevalent blood-feeding arthropods, and they act as vectors and reservoirs for numerous pathogens. Sialotranscriptomic characterizations of tick responses to blood feeding and pathogen infections can offer new insights into the molecular interplay occurring at the tick-host-pathogen interface. In the present study, we aimed to identify and characterize Rhipicephalus bursa salivary gland (SG) genes that were differentially expressed in response to blood feeding and Babesia ovis infection. Our experimental approach consisted of RNA sequencing of SG from three different tick samples, fed-infected, fed-uninfected, and unfed-uninfected, for characterization and inter-comparison. Overall, 7,272 expressed sequence tags (ESTs) were constructed from unfed-uninfected, 13,819 ESTs from fed-uninfected, and 15,292 ESTs from fed-infected ticks. Two catalogs of transcripts that were differentially expressed in response to blood feeding and B. ovis infection were produced. Four genes coding for a putative vitellogenin-3, lachesin, a glycine rich protein, and a secreted cement protein were selected for RNA interference functional studies. A reduction of 92, 65, and 51% was observed in vitellogenin-3, secreted cement, and lachesin mRNA levels in SG, respectively. The vitellogenin-3 knockdown led to increased tick mortality, with 77% of ticks dying post-infestation. The reduction of the secreted cement protein-mRNA levels resulted in 46% of ticks being incapable of correctly attaching to the host and significantly lower female weights post-feeding in comparison to the control group. The lachesin knockdown resulted in a 70% reduction of the levels associated with B. ovis infection in R. bursa SG and 70% mortality. These results improved our understanding of the role of tick SG genes in Babesia infection/proliferation and tick feeding. Moreover, lachesin, vitellogenin-3, and secreted cement proteins were validated as candidate protective antigens for the development of novel tick and tick-borne disease control measures.
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Affiliation(s)
- Sandra Antunes
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal.,Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Joana Couto
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal.,Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Joana Ferrolho
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal.,Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Fábio Rodrigues
- Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
| | - João Nobre
- Instituto Nacional de Investigação Agrária e Veterinária, Pólo de Santarém, Vale de Santarém, Portugal
| | - Ana S Santos
- Instituto Nacional de Saúde Doutor Ricardo Jorge, Centro de Estudos de Vectores e Doenças Infecciosas Dr. Francisco Cambournac (CEVDI/INSA), Águas de Moura, Portugal
| | - M Margarida Santos-Silva
- Instituto Nacional de Saúde Doutor Ricardo Jorge, Centro de Estudos de Vectores e Doenças Infecciosas Dr. Francisco Cambournac (CEVDI/INSA), Águas de Moura, Portugal
| | - José de la Fuente
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM, Ciudad Real, Spain.,Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, United States
| | - Ana Domingos
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal.,Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
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