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Pei T, Zhang M, Gao Z, Li L, Bing Z, Meng J, Nwanade CF, Yuan C, Yu Z, Liu J. Molecular characterization and induced changes of histone acetyltransferases in the tick Haemaphysalis longicornis in response to cold stress. Parasit Vectors 2024; 17:218. [PMID: 38735919 PMCID: PMC11089763 DOI: 10.1186/s13071-024-06288-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 04/19/2024] [Indexed: 05/14/2024] Open
Abstract
BACKGROUND Epigenetic modifications of histones play important roles in the response of eukaryotic organisms to environmental stress. However, many histone acetyltransferases (HATs), which are responsible for histone acetylation, and their roles in mediating the tick response to cold stress have yet to be identified. In the present study, HATs were molecularly characterized and their associations with the cold response of the tick Haemaphysalis longicornis explored. METHODS HATs were characterized by using polymerase chain reaction (PCR) based on published genome sequences, followed by multiple bioinformatic analyses. The differential expression of genes in H. longicornis under different cold treatment conditions was evaluated using reverse transcription quantitative PCR (RT-qPCR). RNA interference was used to explore the association of HATs with the cold response of H. longicornis. RESULTS Two HAT genes were identified in H. longicornis (Hl), a GCN5-related N-acetyltransferase (henceforth HlGNAT) and a type B histone acetyltransferase (henceforth HlHAT-B), which are respectively 960 base pairs (bp) and 1239 bp in length. Bioinformatics analysis revealed that HlGNAT and HlHAT-B are unstable hydrophilic proteins characterized by the presence of the acetyltransferase 16 domain and Hat1_N domain, respectively. RT-qPCR revealed that the expression of HlGNAT and HlHAT-B decreased after 3 days of cold treatment, but gradually increased with a longer period of cold treatment. The mortality rate following knockdown of HlGNAT or HlHAT-B by RNA interference, which was confirmed by RT-qPCR, significantly increased (P < 0.05) when H. longicornis was treated at the lowest lethal temperature (- 14 °C) for 2 h. CONCLUSIONS The findings demonstrate that HATs may play a crucial role in the cold response of H. longicornis. Thus further research is warranted to explore the mechanisms underlying the epigenetic regulation of the cold response in ticks.
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Affiliation(s)
- Tingwei Pei
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
| | - Miao Zhang
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
| | - Ziwen Gao
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
| | - Lu Li
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
| | - Ziyan Bing
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
| | - Jianglei Meng
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
| | - Chuks Fidel Nwanade
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
| | - Chaohui Yuan
- The Professional and Technical Center of Hebei Administration for Market Regulation, Shijiazhuang, 050024, China
| | - Zhijun Yu
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China.
| | - Jingze Liu
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China.
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Rosche KL, Hurtado J, Fisk EA, Vosbigian KA, Warren AL, Sidak-Loftis LC, Wright SJ, Ramirez-Zepp E, Park JM, Shaw DK. PERK-mediated antioxidant response is key for pathogen persistence in ticks. mSphere 2023; 8:e0032123. [PMID: 37733353 PMCID: PMC10597351 DOI: 10.1128/msphere.00321-23] [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: 06/14/2023] [Accepted: 07/31/2023] [Indexed: 09/22/2023] Open
Abstract
A crucial phase in the life cycle of tick-borne pathogens is the time spent colonizing and persisting within the arthropod. Tick immunity is emerging as a key force shaping how transmissible pathogens interact with the vector. How pathogens remain in the tick despite immunological pressure remains unknown. In persistently infected Ixodes scapularis, we found that Borrelia burgdorferi (causative agent of Lyme disease) and Anaplasma phagocytophilum (causative agent of granulocytic anaplasmosis) activate a cellular stress pathway mediated by the endoplasmic reticulum receptor PKR-like ER kinase (PERK) and the central regulatory molecule eIF2α. Disabling the PERK pathway through pharmacological inhibition and RNA interference (RNAi) significantly decreased microbial numbers. In vivo RNAi of the PERK pathway not only reduced the number of A. phagocytophilum and B. burgdorferi colonizing larvae after a bloodmeal but also significantly reduced the number of bacteria that survive the molt. An investigation into PERK pathway-regulated targets revealed that A. phagocytophilum and B. burgdorferi induce activity of the antioxidant response regulator, nuclear factor erythroid 2-related factor 2 (Nrf2). Tick cells deficient for nrf2 expression or PERK signaling showed accumulation of reactive oxygen and nitrogen species in addition to reduced microbial survival. Supplementation with antioxidants rescued the microbicidal phenotype caused by blocking the PERK pathway. Altogether, our study demonstrates that the Ixodes PERK pathway is activated by transmissible microbes and facilitates persistence in the arthropod by potentiating an Nrf2-regulated antioxidant environment. IMPORTANCE Recent advances demonstrate that the tick immune system recognizes and limits the pathogens they transmit. Innate immune mediators such as antimicrobial peptides and reactive oxygen/nitrogen species are produced and restrict microbial survival. It is currently unclear how pathogens remain in the tick, despite this immune assault. We found that an antioxidant response controlled by the PERK branch of the unfolded protein response is activated in ticks that are persistently infected with Borrelia burgdorferi (Lyme disease) or Anaplasma phagocytophilum (granulocytic anaplasmosis). The PERK pathway induces the antioxidant response transcription factor, Nrf2, which coordinates a gene network that ultimately neutralizes reactive oxygen and nitrogen species. Interfering with this signaling cascade in ticks causes a significant decline in pathogen numbers. Given that innate immune products can cause collateral damage to host tissues, we speculate that this is an arthropod-driven response aimed at minimizing damage to "self" that also inadvertently benefits the pathogen. Collectively, our findings shed light on the mechanistic push and pull between tick immunity and pathogen persistence within the arthropod vector.
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Affiliation(s)
- Kristin L. Rosche
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Joanna Hurtado
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
- School of Molecular Biosciences, Washington State University, Pullman, Washington, USA
| | - Elis A. Fisk
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Kaylee A. Vosbigian
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Ashley L. Warren
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Lindsay C. Sidak-Loftis
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Sarah J. Wright
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Elisabeth Ramirez-Zepp
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Jason M. Park
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Dana K. Shaw
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
- School of Molecular Biosciences, Washington State University, Pullman, Washington, USA
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Pei T, Zhang T, Zhang M, Nwanade CF, Wang R, Wang Z, Bai R, Yu Z, Liu J. Molecular characterization and modulated expression of histone acetyltransferases during cold response of the tick Dermacentor silvarum (Acari: Ixodidae). Parasit Vectors 2023; 16:358. [PMID: 37817288 PMCID: PMC10566034 DOI: 10.1186/s13071-023-05955-2] [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: 07/09/2023] [Accepted: 08/28/2023] [Indexed: 10/12/2023] Open
Abstract
BACKGROUND Histone acetylation is involved in the regulation of stress responses in multiple organisms. Dermacentor silvarum is an important vector tick species widely distributed in China, and low temperature is a crucial factor restricting the development of its population. However, knowledge of the histone acetyltransferases and epigenetic mechanisms underlying cold-stress responses in this tick species is limited. METHODS Histone acetyltransferase genes were characterized in D. silvarum, and their relative expressions were determined using qPCR during cold stress. The association and modulation of histone acetyltransferase genes were further explored using RNA interference, and both the H3K9 acetylation level and relative expression of KAT5 protein were evaluated using western blotting. RESULTS Three histone acetyltransferase genes were identified and named as DsCREBBP, DsKAT6B, and DsKAT5. Bioinformatics analysis showed that they were unstable hydrophilic proteins, characterized by the conserved structures of CBP (ZnF_TAZ), PHA03247 super family, Creb_binding, and MYST(PLN00104) super family. Fluorescence quantitative PCR showed that the expression of DsCREBBP, DsKAT6B, and DsKAT5 increased after 3 days of cold treatment, with subsequent gradual decreases, and was lowest on day 9. Western blotting showed that both the H3K9 acetylation level and relative expression of KAT5 in D. silvarum increased after treatment at - 4, 4, and 8 °C for 3 and 6 days, whereas they decreased significantly after a 9-day treatment. RNA interference induced significant gene silencing, and the mortality rate of D. silvarum significantly increased at the respective semi-lethal temperatures. CONCLUSION These results imply that histone acetyltransferases play an important role in tick adaptation to low temperatures and lay a foundation for further understanding of the epigenetic regulation of histone acetylation in cold-stressed ticks. Further research is needed to elucidate the mechanisms underlying histone acetylation during cold stress in ticks.
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Affiliation(s)
- Tingwei Pei
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024 China
| | - Tianai Zhang
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024 China
| | - Miao Zhang
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024 China
| | - Chuks F. Nwanade
- Department of Entomology and Plant Pathology, The University of Tennessee, Knoxville, TN USA
| | - Ruotong Wang
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024 China
| | - Zihao Wang
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024 China
| | - Ruwei Bai
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024 China
| | - Zhijun Yu
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024 China
| | - Jingze Liu
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024 China
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Rosche KL, Hurtado J, Fisk EA, Vosbigian KA, Warren AL, Sidak-Loftis LC, Wright SJ, Ramirez-Zepp E, Park JM, Shaw DK. PERK-mediated antioxidant response is key for pathogen persistence in ticks. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.30.542958. [PMID: 37398437 PMCID: PMC10312570 DOI: 10.1101/2023.05.30.542958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
A crucial phase in the lifecycle of tick-borne pathogens is the time spent colonizing and persisting within the arthropod. Tick immunity is emerging as a key force shaping how transmissible pathogens interact with the vector. How pathogens remain in the tick despite immunological pressure remains unknown. In persistently infected Ixodes scapularis , we found that Borrelia burgdorferi (Lyme disease) and Anaplasma phagocytophilum (granulocytic anaplasmosis) activate a cellular stress pathway mediated by the endoplasmic reticulum receptor PERK and the central regulatory molecule, eIF2α. Disabling the PERK pathway through pharmacological inhibition and RNAi significantly decreased microbial numbers. In vivo RNA interference of the PERK pathway not only reduced the number of A. phagocytophilum and B. burgdorferi colonizing larvae after a bloodmeal, but also significantly reduced the number of bacteria that survive the molt. An investigation into PERK pathway-regulated targets revealed that A. phagocytophilum and B. burgdorferi induce activity of the antioxidant response regulator, Nrf2. Tick cells deficient for nrf2 expression or PERK signaling showed accumulation of reactive oxygen and nitrogen species in addition to reduced microbial survival. Supplementation with antioxidants rescued the microbicidal phenotype caused by blocking the PERK pathway. Altogether, our study demonstrates that the Ixodes PERK pathway is activated by transmissible microbes and facilitates persistence in the arthropod by potentiating an Nrf2-regulated antioxidant environment.
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Affiliation(s)
- Kristin L. Rosche
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Joanna Hurtado
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
- School of Molecular Biosciences, Washington State University, Pullman, Washington, USA
| | - Elis A. Fisk
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Kaylee A. Vosbigian
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Ashley L. Warren
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Lindsay C. Sidak-Loftis
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Sarah J. Wright
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Elisabeth Ramirez-Zepp
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Jason M. Park
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Dana K. Shaw
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
- School of Molecular Biosciences, Washington State University, Pullman, Washington, USA
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Ribeiro JMC, Bayona-Vásquez NJ, Budachetri K, Kumar D, Frederick JC, Tahir F, Faircloth BC, Glenn TC, Karim S. A draft of the genome of the Gulf Coast tick, Amblyomma maculatum. Ticks Tick Borne Dis 2023; 14:102090. [PMID: 36446165 PMCID: PMC9898150 DOI: 10.1016/j.ttbdis.2022.102090] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 10/17/2022] [Accepted: 11/20/2022] [Indexed: 11/24/2022]
Abstract
The Gulf Coast tick, Amblyomma maculatum, inhabits the Southeastern states of the USA bordering the Gulf of Mexico, Mexico, and other Central and South American countries. More recently, its U.S. range has extended West to Arizona and Northeast to New York state and Connecticut. It is a vector of Rickettsia parkeri and Hepatozoon americanum. This tick species has become a model to study tick/Rickettsia interactions. To increase our knowledge of the basic biology of A. maculatum we report here a draft genome of this tick and an extensive functional classification of its proteome. The DNA from a single male tick was used as a genomic source, and a 10X genomics protocol determined 28,460 scaffolds having equal or more than 10 Kb, totaling 1.98 Gb. The N50 scaffold size was 19,849 Kb. The BRAKER pipeline was used to find the protein-coding gene boundaries on the assembled A. maculatum genome, discovering 237,921 CDS. After trimming and classifying the transposable elements, bacterial contaminants, and truncated genes, a set of 25,702 were annotated and classified as the core gene products. A BUSCO analysis revealed 83.4% complete BUSCOs. A hyperlinked spreadsheet is provided, allowing browsing of the individual gene products and their matches to several databases.
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Affiliation(s)
- Jose M C Ribeiro
- NIAID NIH Laboratory of Malaria and Vector Research, Bethesda, MD 20892-8132, USA.
| | - Natalia J Bayona-Vásquez
- Department of Environmental Health Science and Georgia Genomics Facility, Environmental Health Science Building, University of Georgia, Athens, GA 30602, USA
| | - Khemraj Budachetri
- Center for Molecular and Cellular Biology, School of Biological, Environmental, and Earth Sciences, 118 College Drive, 5018, University of Southern Mississippi, Hattiesburg, MS 39406, USA; The Ohio State University, Columbus, OH 43210, USA
| | - Deepak Kumar
- Department of Environmental Health Science and Georgia Genomics Facility, Environmental Health Science Building, University of Georgia, Athens, GA 30602, USA
| | - Julia Catherine Frederick
- Department of Environmental Health Science and Georgia Genomics Facility, Environmental Health Science Building, University of Georgia, Athens, GA 30602, USA
| | - Faizan Tahir
- Center for Molecular and Cellular Biology, School of Biological, Environmental, and Earth Sciences, 118 College Drive, 5018, University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Brant C Faircloth
- Department of Biological Sciences, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803, USA
| | - Travis C Glenn
- Department of Environmental Health Science and Georgia Genomics Facility, Environmental Health Science Building, University of Georgia, Athens, GA 30602, USA
| | - Shahid Karim
- Center for Molecular and Cellular Biology, School of Biological, Environmental, and Earth Sciences, 118 College Drive, 5018, University of Southern Mississippi, Hattiesburg, MS 39406, USA
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Guizzo MG, Budachetri K, Adegoke A, Ribeiro JMC, Karim S. Rickettsia parkeri infection modulates the sialome and ovariome of the Gulf coast tick, Amblyomma maculatum. Front Microbiol 2022; 13:1023980. [PMID: 36439862 PMCID: PMC9684213 DOI: 10.3389/fmicb.2022.1023980] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 10/06/2022] [Indexed: 07/21/2023] Open
Abstract
The Gulf Coast tick, Amblyomma maculatum, is a vector of several tick-borne pathogens, including Rickettsia parkeri. The ability of R. parkeri to persist within the tick population through transovarial and transstadial transmission, without apparently harming the ticks, contributes to the pathogen's perpetuation in the tick population. Previous studies have shown that the R. parkeri load in A. maculatum is regulated by the tick tissues' oxidant/antioxidant balance and the non-pathogenic tick microbiome. To obtain further insights into the interaction between tick and pathogen, we performed a bulk RNA-Seq for differential transcriptomic analysis of ovaries and salivary glands from R. parkeri-infected and uninfected ticks over the feeding course on a host. The most differentially expressed functional category was of bacterial origin, exhibiting a massive overexpression of bacterial transcripts in response to the R. parkeri infection. Candidatus Midichloria mitochondrii and bacteria from the genus Rickettsia were mainly responsible for the overexpression of bacterial transcripts. Host genes were also modulated in R. parkeri-infected tick organs. A similar number of host transcripts from all analyzed functional categories was negatively and positively modulated, revealing a global alteration of the A. maculatum transcriptome in response to pathogen infection. R. parkeri infection led to an increase in salivary transcripts involved in blood feeding success as well as a decrease in ovarian immune transcripts. We hypothesize that these transcriptional alterations facilitate pathogen persistence and transmission within tick population.
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Affiliation(s)
- Melina Garcia Guizzo
- Vector Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Khemraj Budachetri
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Abdulsalam Adegoke
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Jose M. C. Ribeiro
- Vector Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Shahid Karim
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
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Ali A, Zeb I, Alouffi A, Zahid H, Almutairi MM, Ayed Alshammari F, Alrouji M, Termignoni C, Vaz IDS, Tanaka T. Host Immune Responses to Salivary Components - A Critical Facet of Tick-Host Interactions. Front Cell Infect Microbiol 2022; 12:809052. [PMID: 35372098 PMCID: PMC8966233 DOI: 10.3389/fcimb.2022.809052] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 02/04/2022] [Indexed: 12/15/2022] Open
Abstract
Tick sialome is comprised of a rich cocktail of bioactive molecules that function as a tool to disarm host immunity, assist blood-feeding, and play a vibrant role in pathogen transmission. The adaptation of the tick's blood-feeding behavior has lead to the evolution of bioactive molecules in its saliva to assist them to overwhelm hosts' defense mechanisms. During a blood meal, a tick secretes different salivary molecules including vasodilators, platelet aggregation inhibitors, anticoagulants, anti-inflammatory proteins, and inhibitors of complement activation; the salivary repertoire changes to meet various needs such as tick attachment, feeding, and modulation or impairment of the local dynamic and vigorous host responses. For instance, the tick's salivary immunomodulatory and cement proteins facilitate the tick's attachment to the host to enhance prolonged blood-feeding and to modulate the host's innate and adaptive immune responses. Recent advances implemented in the field of "omics" have substantially assisted our understanding of host immune modulation and immune inhibition against the molecular dynamics of tick salivary molecules in a crosstalk between the tick-host interface. A deep understanding of the tick salivary molecules, their substantial roles in multifactorial immunological cascades, variations in secretion, and host immune responses against these molecules is necessary to control these parasites. In this article, we reviewed updated knowledge about the molecular mechanisms underlying host responses to diverse elements in tick saliva throughout tick invasion, as well as host defense strategies. In conclusion, understanding the mechanisms involved in the complex interactions between the tick salivary components and host responses is essential to decipher the host defense mechanisms against the tick evasion strategies at tick-host interface which is promising in the development of effective anti-tick vaccines and drug therapeutics.
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Affiliation(s)
- Abid Ali
- Department of Zoology, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Ismail Zeb
- Department of Zoology, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Abdulaziz Alouffi
- King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Hafsa Zahid
- Department of Zoology, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Mashal M. Almutairi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Fahdah Ayed Alshammari
- College of Sciences and Literature Microbiology, Nothern Border University, Rafha, Saudi Arabia
| | - Mohammed Alrouji
- College of Applied Medical Sciences, Shaqra University, Shaqra, Saudi Arabia
| | - Carlos Termignoni
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Itabajara da Silva Vaz
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Tetsuya Tanaka
- Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
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8
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Stockmal KA, Downs LP, Davis AN, Kemp LK, Karim S, Morgan SE. Cationic Glycopolyelectrolytes for RNA Interference in Tick Cells. Biomacromolecules 2021; 23:34-46. [PMID: 34793129 DOI: 10.1021/acs.biomac.1c00824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The black-legged tick (Ixodes scapularis) is the primary vector for bacteria that cause Lyme disease (Borrelia burgdorferi), where numerous glycosylated tick proteins are involved at the interface of vector-host-pathogen interactions. Reducing the expression of key tick proteins, such as selenoprotein K (SelK), through RNA interference is a promising approach to reduce pathogen transmission, but efficient delivery of nucleic acids to arthropods has proven challenging. While cationic glycopolymers have been used as nonviral gene delivery vehicles in mammalian cells, their use in arthropod or insect gene transfection has not been established. In this study, statistical acrylamide-based cationic glycopolymers with glucose or galactose pendant groups were synthesized by reversible addition-fragmentation chain transfer polymerization, and the effects of the saccharide pendant group and cationic monomer loading on polymer cytotoxicity, RNA complexation, and SelK gene knockdown in ISE6 cells were evaluated. All polymers exhibited low cytotoxicity, yet RNA/copolymer complex cell uptake and gene knockdown were highly dependent on the saccharide structure and the N:P (amino to phosphate groups) ratio.
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Affiliation(s)
- Kelli A Stockmal
- School of Polymer Science and Engineering, The University of Southern Mississippi, Hattiesburg, Mississippi 39406-5050, United States
| | - Latoyia P Downs
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi 39406-5050, United States
| | - Ashley N Davis
- School of Polymer Science and Engineering, The University of Southern Mississippi, Hattiesburg, Mississippi 39406-5050, United States
| | - Lisa K Kemp
- School of Polymer Science and Engineering, The University of Southern Mississippi, Hattiesburg, Mississippi 39406-5050, United States
| | - Shahid Karim
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi 39406-5050, United States.,Center for Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, Mississippi 39406-5050, United States
| | - Sarah E Morgan
- School of Polymer Science and Engineering, The University of Southern Mississippi, Hattiesburg, Mississippi 39406-5050, United States
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9
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Choubdar N, Karimian F, Koosha M, Oshaghi MA. An integrated overview of the bacterial flora composition of Hyalomma anatolicum, the main vector of CCHF. PLoS Negl Trop Dis 2021; 15:e0009480. [PMID: 34106924 PMCID: PMC8216544 DOI: 10.1371/journal.pntd.0009480] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 06/21/2021] [Accepted: 05/16/2021] [Indexed: 12/26/2022] Open
Abstract
The microbial flora associated with Hyalomma anatolicum ticks was investigated using culture-dependent (CD) and independent (next generation sequencing, NGS) methods. The bacterial profiles of different organs, development stages, sexes, and of host cattle skins were analyzed using the CD method. The egg and female gut microbiota were investigated using NGS. Fourteen distinct bacterial strains were identified using the CD method, of which Bacillus subtilis predominated in eggs, larval guts and in adult female and male guts, suggesting probable transovarial transmission. Bacillus velezensis and B. subtilis were identified in cattle skin and tick samples, suggesting that skin is the origin of tick bacteria. H.anatolicum males harbour lower bacterial diversity and composition than females. The NGS analysis revealed five different bacterial phyla across all samples, Proteobacteria contributing to >95% of the bacteria. In all, 56611sequences were generated representing 6,023 OTUs per female gut and 421 OTUs per egg. Francisellaceae family and Francisella make up the vast majority of the OTUs. Our findings are consistent with interference between Francisella and Rickettsia. The CD method identified bacteria, such B. subtilis that are candidates for vector control intervention approaches such paratransgenesis whereas NGS revealed high Francisella spp. prevalence, indicating that integrated methods are more accurate to characterize microbial community and diversity.
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Affiliation(s)
- Nayyereh Choubdar
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Fateh Karimian
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mona Koosha
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Ali Oshaghi
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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10
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Karim S, Kumar D, Budachetri K. Recent advances in understanding tick and rickettsiae interactions. Parasite Immunol 2021; 43:e12830. [PMID: 33713348 DOI: 10.1111/pim.12830] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 12/31/2022]
Abstract
Ticks are haematophagous arthropods with unique molecular mechanisms for digesting host blood meal while acting as vectors for various pathogens of public health significance. The tick's pharmacologically active saliva plays a fundamental role in modulating the host's immune system for several days to weeks, depending on the tick species. The vector tick has also developed sophisticated molecular mechanisms to serve as a competent vector for pathogens, including the spotted fever group (SFG) rickettsiae. Evidence is still inadequate concerning tick-rickettsiae-host interactions and saliva-assisted transmission of the pathogen to the mammalian host. Rickettsia parkeri, of the SFG rickettsia, can cause a milder version of Rocky Mountain spotted fever known as American Boutonneuse fever. The Gulf Coast tick (Amblyomma maculatum) often transmits this pathogenic rickettsia in the USA. This review discusses the knowledge gap concerning tick-rickettsiae-host interactions by highlighting the SFG rickettsia and the Am maculatum model system. Filling this knowledge gap will provide a better understanding of the tick-rickettsiae-host interactions in disease causation, which will be crucial for developing effective methods for preventing tick-borne diseases.
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Affiliation(s)
- Shahid Karim
- Center for Molecular and Cellular Biosciences, School of Biological. Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, USA
| | - Deepak Kumar
- Center for Molecular and Cellular Biosciences, School of Biological. Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, USA
| | - Khemraj Budachetri
- Center for Molecular and Cellular Biosciences, School of Biological. Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, USA.,The Ohio State University, Columbus, OH, USA
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11
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Uribe JE, Nava S, Murphy KR, Tarragona EL, Castro LR. Characterization of the complete mitochondrial genome of Amblyomma ovale, comparative analyses and phylogenetic considerations. EXPERIMENTAL & APPLIED ACAROLOGY 2020; 81:421-439. [PMID: 32564254 DOI: 10.1007/s10493-020-00512-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/12/2020] [Indexed: 06/11/2023]
Abstract
In this study, we sequenced two complete mitochondrial genomes of Amblyomma ovale, a tick of public health importance. Sequencing two distinct individuals, the resulting mitochondrial genomes were 14,756 and 14,760 bp in length and maintained the same gene order previously reported in Amblyomma. These were combined with RNA-seq derived mitochondrial sequences from three additional species, Amblyomma aureolatum, Amblyomma maculatum, and Amblyomma moreliae, to carry out mitogenome comparative and evolutionary analyses against all previously published tick mitochondrial genomes. We described a derivative genome rearrangement that isolates Ixodes from the remaining Ixodidae and consists of both a reverse translocation as well as an event of Tandem Duplication Random Loss. Genetic distance analyses indicated that cox2, nd1, nd5, and 16S are good candidates for future population studies in A. ovale. The phylogenetic analyses corroborated the utility of complete mitochondrial genomes as phylogenetic markers within the group. This study further supplements the genome information available for Amblyomma and facilitates future evolutionary and population genetic studies within the genus.
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Affiliation(s)
- Juan E Uribe
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales (MNCN-CSIC), c/ José Gutiérrez Abascal 2, 28006, Madrid, Spain.
- Department of Invertebrate Zoology, Smithsonian Institution, National Museum of Natural History, 10th St. & Constitutional Ave. NW, Washington, DC, 20560, USA.
| | - Santiago Nava
- Instituto Nacional de Tecnología Agropecuaria, Estación Experimental Agropecuaria Rafaela, Consejo Nacional de Investigaciones Científicas y Técnicas, CC 22, Rafaela, CP 2300, Santa Fe, Argentina
| | - Katherine R Murphy
- Laboratories of Analytical Biology, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20013, USA
| | - Evelina L Tarragona
- Instituto Nacional de Tecnología Agropecuaria, Estación Experimental Agropecuaria Rafaela, Consejo Nacional de Investigaciones Científicas y Técnicas, CC 22, Rafaela, CP 2300, Santa Fe, Argentina
| | - Lyda R Castro
- Grupo de Investigación Evolución, Sistemática y Ecología Molecular (GIESEMOL), Universidad del Magdalena, Santa Marta, Magdalena, Colombia
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Hernandez EP, Talactac MR, Fujisaki K, Tanaka T. The case for oxidative stress molecule involvement in the tick-pathogen interactions -an omics approach. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 100:103409. [PMID: 31200008 DOI: 10.1016/j.dci.2019.103409] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 05/30/2019] [Accepted: 06/03/2019] [Indexed: 06/09/2023]
Abstract
The blood-feeding behavior of ticks has resulted in them becoming one of the most important vectors of disease-causing pathogens. Ticks possess a well-developed innate immune system to counter invading pathogens. However, the coevolution of ticks with tick-borne pathogens has adapted these pathogens to the tick's physiology and immune response through several mechanisms including transcriptional regulation. The recent development in tick and tick-borne disease research greatly involved the "omics" approach. The omics approach takes a look en masse at the different genes, proteins, metabolomes, and the microbiome of the ticks that could be differentiated during pathogen infection. Data from this approach revealed that oxidative stress-related molecules in ticks are differentiated and possibly being exploited by the pathogens to evade the tick's immune response. In this study, we review and discuss transcriptomic and proteomic data for some oxidative stress molecules differentially expressed during pathogen infection. We also discuss metabolomics and microbiome data as well as functional genomics in order to provide insight into the tick-pathogen interaction.
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Affiliation(s)
- Emmanuel Pacia Hernandez
- Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0056, Japan; Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi, 753-8515, Japan
| | - Melbourne Rio Talactac
- Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0056, Japan; Department of Clinical and Population Health, College of Veterinary Medicine and Biomedical Sciences, Cavite State University, Cavite, 4122, Philippines
| | - Kozo Fujisaki
- National Agricultural and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan
| | - Tetsuya Tanaka
- Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0056, Japan; Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi, 753-8515, Japan.
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13
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Pérez-Sánchez R, Manzano-Román R, Obolo-Mvoulouga P, Oleaga A. Function-guided selection of midgut antigens from Ornithodoros erraticus ticks and an evaluation of their protective efficacy in rabbits. Vet Parasitol 2019; 272:1-12. [PMID: 31395198 DOI: 10.1016/j.vetpar.2019.06.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/24/2019] [Accepted: 06/26/2019] [Indexed: 10/26/2022]
Abstract
The identification of candidate protective antigens for the development of tick vaccines may be approached by selecting antigen candidates that play key biological functions. Tick midgut proteins that play essential functions in tick survival and disease transmission are upregulated in response to blood feeding and digestion. In this study, Ornithodoros erraticus midgut transcriptomic and proteomic data upon feeding were inspected to select functionally relevant antigens to be assessed as vaccine candidate antigens. For this, we primarily focused on proteins with relevant biological functions in key physiological processes for ticks and tick-host-pathogen interactions. Later, we used additional criteria based on overexpression after feeding, predicted antigenicity and cellular localisation, resulting in the selection of four theoretical candidates, two aquaporins (OeAQP, OeAQP1), one ABC transporter (OeABC) and one selenoprotein T (OeSEL). Rabbit vaccination with synthetic immunogenic peptides designed from the extracellular antigenic regions of the selected candidates induced humoral responses that reduced tick feeding and reproduction performance. Both AQPs and OeSEL demonstrated significant protection efficacy against the homologous species O. erraticus, but lower non-significant cross-species protection against Ornithodoros moubata. Conversely, OeABC showed no protection against the homologous species O. erraticus, but significant cross-species protection against O. moubata. These results are the first demonstration of the protective potential of argasid aquaporins, suggesting that they might be included in vaccines for the control of multiple tick species. Additionally, these results also unveiled two novel protective antigens from argasid ticks, OeABC and OeSEL, belonging to functional protein families that have never been explored as a source of vaccine candidates and are deserving of further studies. Finally, our data add value to the midgut as a protective candidate antigen source in argasids for the control of tick infestations.
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Affiliation(s)
- Ricardo Pérez-Sánchez
- Parasitología Animal, Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA, CSIC), Cordel de Merinas, 40-52, 37008 Salamanca, Spain.
| | - Raúl Manzano-Román
- Parasitología Animal, Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA, CSIC), Cordel de Merinas, 40-52, 37008 Salamanca, Spain.
| | - Prosper Obolo-Mvoulouga
- Parasitología Animal, Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA, CSIC), Cordel de Merinas, 40-52, 37008 Salamanca, Spain.
| | - Ana Oleaga
- Parasitología Animal, Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA, CSIC), Cordel de Merinas, 40-52, 37008 Salamanca, Spain.
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14
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Kumar D, Embers M, Mather TN, Karim S. Is selenoprotein K required for Borrelia burgdorferi infection within the tick vector Ixodes scapularis? Parasit Vectors 2019; 12:289. [PMID: 31174589 PMCID: PMC6555942 DOI: 10.1186/s13071-019-3548-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/01/2019] [Indexed: 12/18/2022] Open
Abstract
Background Tick selenoproteins are involved in regulating oxidative and endoplasmic reticulum stress during prolonged tick feeding on mammalian hosts. How selenoproteins are activated upon tick-borne pathogen infection is yet to be defined. Methods To examine the functional role of selenoprotein K in Borrelia burgdorferi infection within the tick host Ixodes scapularis, RNA interference (RNAi)-based gene silencing was performed. Results Selenoprotein K is an endoplasmic reticulum (ER)-resident protein and a component of the ERAD complex involved in ER homeostasis. A qRT-PCR assay revealed the significant upregulation of selenogene K (selenoK) expression in B. burgdorferi-infected tick tissues. Silencing of the selenoK transcript significantly depleted B. burgdorferi copies within the infected tick tissues. Upon selenoK knockdown, another component of the ERAD complex, selenoprotein S (selenoS), was significantly upregulated, suggesting a compensatory mechanism to maintain ER homeostasis within the tick tissues. Knockdown of selenoK also upregulated ER stress-related unfolded protein response (UPR) pathway components, ATF6 and EIF2. Conclusions The exact mechanisms that contribute to depletion of B. burgdorferi upon selenoK knockdown is yet to be determined, but this study suggests that selenoK may play a vital role in the survival of B. burgdorferi within the tick host. Electronic supplementary material The online version of this article (10.1186/s13071-019-3548-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Deepak Kumar
- Department of of Cell and Molecular Biology, School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - Monica Embers
- Division of Immunology, Tulane National Primate Research Center, Covington, LA, 70455, USA
| | - Thomas N Mather
- Center for Vector-Borne Disease, University of Rhode Island, Kingston, RI, 02881, USA
| | - Shahid Karim
- Department of of Cell and Molecular Biology, School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
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15
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Saito TB, Bechelli J, Smalley C, Karim S, Walker DH. Vector Tick Transmission Model of Spotted Fever Rickettsiosis. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 189:115-123. [PMID: 30315767 DOI: 10.1016/j.ajpath.2018.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 09/06/2018] [Accepted: 09/10/2018] [Indexed: 12/13/2022]
Abstract
Many aspects of rickettsial infections have been characterized, including pathogenic and immune pathways and mechanisms of rickettsial survival within the vertebrate host and tick vector. However, very few studies are focused on the complex pathogen-vector-host interactions during tick feeding. Therefore, our objective was to develop a tick transmission model of the spotted fever group of rickettsial infections to study the initial events in disease development. The most appropriate strain of mouse was identified for evaluation as a transmission model, and the course of infection, bacterial levels, histopathologic changes, and antibody response during tick transmission in mice infested with Amblyomma maculatum ticks carrying the emerging pathogen, Rickettia parkeri, were studied. Results showed distinct clinical signs in C3H/HeN mice infected intravenously, leading to selection of this mouse strain for tick transmission studies. Active infection of animals was observed after tick vector transmission. The bacteria disseminated systemically and spread to several organs at 24 hours after tick attachment, with peak bacterial load at day 6 after tick attachment. Skin, lung, and liver showed the greatest pathologic changes, with inflammatory cellular infiltration and necrosis. These findings indicate the feasibility of using murine infection with R. parkeri by A. maculatum tick transmission as a model to study different aspects of the spotted fever group of rickettsial disease establishment.
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Affiliation(s)
- Tais B Saito
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas.
| | - Jeremy Bechelli
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas
| | - Claire Smalley
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas
| | - Shahid Karim
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, Mississippi
| | - David H Walker
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas
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16
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Budachetri K, Kumar D, Crispell G, Beck C, Dasch G, Karim S. The tick endosymbiont Candidatus Midichloria mitochondrii and selenoproteins are essential for the growth of Rickettsia parkeri in the Gulf Coast tick vector. MICROBIOME 2018; 6:141. [PMID: 30103809 PMCID: PMC6090677 DOI: 10.1186/s40168-018-0524-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 07/30/2018] [Indexed: 05/08/2023]
Abstract
BACKGROUND Pathogen colonization inside tick tissues is a significant aspect of the overall competence of a vector. Amblyomma maculatum is a competent vector of the spotted fever group rickettsiae, Rickettsia parkeri. When R. parkeri colonizes its tick host, it has the opportunity to dynamically interact with not just its host but with the endosymbionts living within it, and this enables it to modulate the tick's defenses by regulating tick gene expression. The microbiome in A. maculatum is dominated by two endosymbiont microbes: a Francisella-like endosymbiont (FLE) and Candidatus Midichloria mitochondrii (CMM). A range of selenium-containing proteins (selenoproteins) in A. maculatum ticks protects them from oxidative stress during blood feeding and pathogen infections. Here, we investigated rickettsial multiplication in the presence of tick endosymbionts and characterized the functional significance of selenoproteins during R. parkeri replication in the tick. RESULTS FLE and CMM were quantified throughout the tick life stages by quantitative PCR in R. parkeri-infected and uninfected ticks. R. parkeri infection was found to decrease the FLE numbers but CMM thrived across the tick life cycle. Our qRT-PCR analysis indicated that the transcripts of genes with functions related to redox (selenogenes) were upregulated in ticks infected with R. parkeri. Three differentially expressed proteins, selenoprotein M, selenoprotein O, and selenoprotein S were silenced to examine their functional significance during rickettsial replication within the tick tissues. Gene silencing of the target genes was found to impair R. parkeri colonization in the tick vector. Knockdown of the selenogenes triggered a compensatory response from other selenogenes, as observed by changes in gene expression, but oxidative stress levels and endoplasmic reticulum stress inside the ticks were also found to have heightened. CONCLUSIONS This study illustrates the potential of this new research model for augmenting our understanding of the pathogen interactions occurring within tick hosts and the important roles that symbionts and various tick factors play in regulating pathogen growth.
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Affiliation(s)
- Khemraj Budachetri
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - Deepak Kumar
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - Gary Crispell
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | | | - Gregory Dasch
- Rickettsial Zoonoses Branch, Centers for Disease Control, Atlanta, GA, 30329, USA
| | - Shahid Karim
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
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17
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Bakshi M, Kim TK, Mulenga A. Disruption of blood meal-responsive serpins prevents Ixodes scapularis from feeding to repletion. Ticks Tick Borne Dis 2018; 9:506-518. [PMID: 29396196 PMCID: PMC5857477 DOI: 10.1016/j.ttbdis.2018.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 01/04/2018] [Accepted: 01/05/2018] [Indexed: 12/29/2022]
Abstract
Serine protease inhibitors (serpins) are thought to mediate the tick's evasion of the host's serine protease-mediated defense pathways such as inflammation and blood clotting. This study describes characterization and target validation of 11 blood meal-responsive serpins that are associated with nymph and adult Ixodes scapularis tick feeding as revealed by quantitative (q)RT-PCR and RNAi silencing analyses. Given the high number of targets, we used combinatorial (co) RNAi silencing to disrupt candidate serpins in two groups (G): seven highly identical and four non-identical serpins based on amino acid identities, here after called GI and GII respectively. We show that injection of both GI and GII co-dsRNA into unfed nymph and adult I. scapularis ticks triggered suppression of cognate serpin mRNA. We show that disruption of GII, but not GI serpins significantly reduced feeding efficiency of both nymph and adult I. scapularis ticks. Knockdown of GII serpin transcripts caused significant respective mortalities of ≤40 and 71% of nymphal and adult ticks that occurred within 24-48 h of attachment. This is significant, as the observed lethality preceded the tick feeding period when transmission of tick borne pathogens is predominant. We suspect that some of the GII serpins (S9, S17, S19 and S32) play roles in the tick detachment process in that upon detachment, mouthparts of GII co-dsRNA injected were covered with a whitish gel-like tissue that could be the tick cement cone. Normally, ticks do not retain tissue on their mouthparts upon detachment. Furthermore, disruption of GII serpins reduced tick blood meal sizes and the adult tick's ability to convert the blood meal to eggs. We discuss our data with reference to tick feeding physiology and conclude that some of the GII serpins are potential targets for anti-tick vaccine development.
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Affiliation(s)
- Mariam Bakshi
- Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, 422 Raymond Stotzer, TAMU 4467, College Station, TX 77843, USA
| | - Tae Kwon Kim
- Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, 422 Raymond Stotzer, TAMU 4467, College Station, TX 77843, USA
| | - Albert Mulenga
- Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, 422 Raymond Stotzer, TAMU 4467, College Station, TX 77843, USA.
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Greay TL, Gofton AW, Paparini A, Ryan UM, Oskam CL, Irwin PJ. Recent insights into the tick microbiome gained through next-generation sequencing. Parasit Vectors 2018; 11:12. [PMID: 29301588 PMCID: PMC5755153 DOI: 10.1186/s13071-017-2550-5] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 11/21/2017] [Indexed: 02/06/2023] Open
Abstract
The tick microbiome comprises communities of microorganisms, including viruses, bacteria and eukaryotes, and is being elucidated through modern molecular techniques. The advent of next-generation sequencing (NGS) technologies has enabled the genes and genomes within these microbial communities to be explored in a rapid and cost-effective manner. The advantages of using NGS to investigate microbiomes surpass the traditional non-molecular methods that are limited in their sensitivity, and conventional molecular approaches that are limited in their scalability. In recent years the number of studies using NGS to investigate the microbial diversity and composition of ticks has expanded. Here, we provide a review of NGS strategies for tick microbiome studies and discuss the recent findings from tick NGS investigations, including the bacterial diversity and composition, influential factors, and implications of the tick microbiome.
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Affiliation(s)
- Telleasha L Greay
- Vector and Waterborne Pathogens Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia.
| | - Alexander W Gofton
- Vector and Waterborne Pathogens Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia
| | - Andrea Paparini
- Vector and Waterborne Pathogens Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia
| | - Una M Ryan
- Vector and Waterborne Pathogens Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia
| | - Charlotte L Oskam
- Vector and Waterborne Pathogens Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia
| | - Peter J Irwin
- Vector and Waterborne Pathogens Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia
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19
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Varela-Stokes AS, Park SH, Kim SA, Ricke SC. Microbial Communities in North American Ixodid Ticks of Veterinary and Medical Importance. Front Vet Sci 2017; 4:179. [PMID: 29104867 PMCID: PMC5654947 DOI: 10.3389/fvets.2017.00179] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/04/2017] [Indexed: 02/05/2023] Open
Abstract
Interest in microbial communities, or microbiota, of blood-feeding arthropods such as ticks (order Parasitiformes, suborder Ixodida) is increasing. Studies on tick microorganisms historically emphasized pathogens of high medical or veterinary importance. Current techniques allow for simultaneous detection of pathogens of interest, non-pathogenic symbionts, like Coxiella-LE and Francisella-LE, and microorganisms of unknown pathogenic potential. While each generation of ticks begins with a maternally acquired repertoire of microorganisms, microhabitats off and on vertebrate hosts can alter the microbiome during the life cycle. Further, blood-feeding may allow for horizontal exchange of various pathogenic microbiota that may or may not also be capable of vertical transmission. Thus, the tick microbiome may be in constant flux. The geographical spread of tick vector populations has resulted in a broader appreciation of tick-borne diseases and tick-associated microorganisms. Over the last decade, next-generation sequencing technology targeting the 16S rRNA gene led to documented snapshots of bacterial communities among life stages of laboratory and field-collected ticks, ticks in various feeding states, and tick tissues. Characterizing tick bacterial communities at population and individual tissue levels may lead to identification of markers for pathogen maintenance, and thus, indicators of disease “potential” rather than disease state. Defining the role of microbiota within the tick may lead to novel control measures targeting tick-bacterial interactions. Here, we review our current understanding of microbial communities for some vectors in the family Ixodidae (hard ticks) in North America, and interpret published findings for audiences in veterinary and medical fields with an appreciation of tick-borne disease.
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Affiliation(s)
- Andrea S Varela-Stokes
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Si Hong Park
- Department of Food Science, Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
| | - Sun Ae Kim
- Department of Food Science, Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
| | - Steven C Ricke
- Department of Food Science, Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
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Budachetri K, Crispell G, Karim S. Amblyomma maculatum SECIS binding protein 2 and putative selenoprotein P are indispensable for pathogen replication and tick fecundity. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 88:37-47. [PMID: 28739494 PMCID: PMC5583717 DOI: 10.1016/j.ibmb.2017.07.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/18/2017] [Accepted: 07/19/2017] [Indexed: 05/20/2023]
Abstract
Selenium, a vital trace element, is incorporated into selenoproteins to produce selenocysteine. Our previous studies have revealed an adaptive co-evolutionary process that has enabled the spotted fever-causing tick-borne pathogen Rickettsia parkeri to survive by manipulating an antioxidant defense system associated with selenium, which includes a full set of selenoproteins and other antioxidants in ticks. Here, we conducted a systemic investigation of SECIS binding protein 2 (SBP2) and putative selenoprotein P (SELENOP) by transcript silencing in adult female Gulf-coast ticks (Amblyomma maculatum). Knockdown of the SBP2 and SELENOP genes depleted the respective transcript levels of these tick selenogenes, and caused differential regulation of other antioxidants. Importantly, the selenium level in the immature and mature tick stages increased significantly after a blood meal, but the selenium level decreased in ticks after the SBP2 and SELENOP knockdowns. Moreover, the SBP2 knockdown significantly impaired both transovarial transmission of R. parkeri to tick eggs and egg hatching. Overall, our data offer new insight into the relationship between the SBP2 selenoprotein synthesis gene and the putative tick SELENOP gene. It also augments our understanding of selenoprotein synthesis, selenium maintenance and utilization, and bacterial colonization of a tick vector.
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Affiliation(s)
- Khemraj Budachetri
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Gary Crispell
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Shahid Karim
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406, USA.
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21
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de Castro MH, de Klerk D, Pienaar R, Rees DJG, Mans BJ. Sialotranscriptomics of Rhipicephalus zambeziensis reveals intricate expression profiles of secretory proteins and suggests tight temporal transcriptional regulation during blood-feeding. Parasit Vectors 2017; 10:384. [PMID: 28797301 PMCID: PMC5553602 DOI: 10.1186/s13071-017-2312-4] [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: 05/09/2017] [Accepted: 07/27/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Ticks secrete a diverse mixture of secretory proteins into the host to evade its immune response and facilitate blood-feeding, making secretory proteins attractive targets for the production of recombinant anti-tick vaccines. The largely neglected tick species, Rhipicephalus zambeziensis, is an efficient vector of Theileria parva in southern Africa but its available sequence information is limited. Next generation sequencing has advanced sequence availability for ticks in recent years and has assisted the characterisation of secretory proteins. This study focused on the de novo assembly and annotation of the salivary gland transcriptome of R. zambeziensis and the temporal expression of secretory protein transcripts in female and male ticks, before the onset of feeding and during early and late feeding. RESULTS The sialotranscriptome of R. zambeziensis yielded 23,631 transcripts from which 13,584 non-redundant proteins were predicted. Eighty-six percent of these contained a predicted start and stop codon and were estimated to be putatively full-length proteins. A fifth (2569) of the predicted proteins were annotated as putative secretory proteins and explained 52% of the expression in the transcriptome. Expression analyses revealed that 2832 transcripts were differentially expressed among feeding time points and 1209 between the tick sexes. The expression analyses further indicated that 57% of the annotated secretory protein transcripts were differentially expressed. Dynamic expression profiles of secretory protein transcripts were observed during feeding of female ticks. Whereby a number of transcripts were upregulated during early feeding, presumably for feeding site establishment and then during late feeding, 52% of these were downregulated, indicating that transcripts were required at specific feeding stages. This suggested that secretory proteins are under stringent transcriptional regulation that fine-tunes their expression in salivary glands during feeding. No open reading frames were predicted for 7947 transcripts. This class represented 17% of the differentially expressed transcripts, suggesting a potential transcriptional regulatory function of long non-coding RNA in tick blood-feeding. CONCLUSIONS The assembled sialotranscriptome greatly expands the sequence availability of R. zambeziensis, assists in our understanding of the transcription of secretory proteins during blood-feeding and will be a valuable resource for future vaccine candidate selection.
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Affiliation(s)
- Minique Hilda de Castro
- Epidemiology, Parasites and Vectors, Onderstepoort Veterinary Research, Agricultural Research Council, Onderstepoort, South Africa.,Biotechnology Platform, Agricultural Research Council, Onderstepoort, South Africa.,College of Agriculture and Environmental Sciences, University of South Africa, Johannesburg, South Africa
| | - Daniel de Klerk
- Epidemiology, Parasites and Vectors, Onderstepoort Veterinary Research, Agricultural Research Council, Onderstepoort, South Africa
| | - Ronel Pienaar
- Epidemiology, Parasites and Vectors, Onderstepoort Veterinary Research, Agricultural Research Council, Onderstepoort, South Africa.,Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - D Jasper G Rees
- Biotechnology Platform, Agricultural Research Council, Onderstepoort, South Africa.,College of Agriculture and Environmental Sciences, University of South Africa, Johannesburg, South Africa
| | - Ben J Mans
- Epidemiology, Parasites and Vectors, Onderstepoort Veterinary Research, Agricultural Research Council, Onderstepoort, South Africa. .,College of Agriculture and Environmental Sciences, University of South Africa, Johannesburg, South Africa. .,Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.
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Budachetri K, Kumar D, Karim S. Catalase is a determinant of the colonization and transovarial transmission of Rickettsia parkeri in the Gulf Coast tick Amblyomma maculatum. INSECT MOLECULAR BIOLOGY 2017; 26:414-419. [PMID: 28370634 PMCID: PMC5496812 DOI: 10.1111/imb.12304] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The Gulf Coast tick (Amblyomma maculatum) has evolved as a competent vector of the spotted-fever group rickettsia, Rickettsia parkeri. In this study, the functional role of catalase, an enzyme responsible for the degradation of toxic hydrogen peroxide, in the colonization of the tick vector by R. parkeri and transovarial transmission of this pathogen to the next tick generation, was investigated. Catalase gene (CAT) expression in midgut, salivary glands and ovarian tissues exhibited a 2-11-fold increase in transcription level upon R. parkeri infection. Depletion of CAT transcripts using an RNA-interference approach significantly reduced R. parkeri infection levels in midgut and salivary gland tissues by 53-63%. The role of CAT in transovarial transmission of R. parkeri was confirmed by simultaneously blocking the transcript and the enzyme by injecting double-stranded RNA for CAT and a catalase inhibitor (3-amino-1,2,4-triazole) into gravid females. Simultaneous inhibition of the CAT transcript and the enzyme significantly reduced the egg conversion ratio with a 44% reduction of R. parkeri transovarial transmission. These data suggest that catalase is required for rickettsial colonization of the tick vector and transovarial transmission to the next generation.
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23
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Kumar D, Budachetri K, Meyers VC, Karim S. Assessment of tick antioxidant responses to exogenous oxidative stressors and insight into the role of catalase in the reproductive fitness of the Gulf Coast tick, Amblyomma maculatum. INSECT MOLECULAR BIOLOGY 2016; 25:283-94. [PMID: 26919203 PMCID: PMC4860135 DOI: 10.1111/imb.12218] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
As obligate blood-sucking ectoparasites, to avoid tissue damage, ticks must neutralize the reactive oxygen species (ROS) generated from uptake and digestion of a bloodmeal. Consequently, ticks utilize a battery of antioxidant molecules, including catalase (CAT), an enzyme that converts hydrogen peroxide (H2 O2 ) into water and oxygen. Here, we investigated the tick antioxidant machinery by exogenous injection of sublethal doses of H2 O2 or paraquat. The relative transcript levels of selected Amblyomma maculatum antioxidant targets in tissues were determined by quantitative reverse transcriptase PCR following treatment. The results showed 2-16-fold increases in target antioxidant gene transcripts, signifying the ability of Am. maculatum to regulate its antioxidant machinery when exposed to increased ROS levels. Next, RNA interference was used to determine the functional role of CAT in haematophagy, redox homeostasis and reproductive fitness. CAT gene silencing was confirmed by transcript depletion within tick tissues; however, CAT knockdown alone did not interfere with tick haematophagy or phenotype, as confirmed by the resulting differential expression of antioxidant genes, thereby indicating an alternative mechanism for ROS control. Interestingly, double stranded RNA of CAT gene (dsCAT) and the CAT inhibitor, 3-aminotriazole, together reduced tick reproductive fitness via a marked reduction in egg mass and larval eclosion rates, highlighting a role for CAT in tick redox-homeostasis, making it a potential target for tick control.
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Affiliation(s)
| | | | | | - Shahid Karim
- Corresponding author: Shahid Karim, Department of Biological Sciences, University of Southern Mississippi, 118 College Drive #5018, Hattiesburg, MS 39406, USA, , Tel: 601-266-6232, Fax: 601-266-5797
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24
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Crispell G, Budachetri K, Karim S. Rickettsia parkeri colonization in Amblyomma maculatum: the role of superoxide dismutases. Parasit Vectors 2016; 9:291. [PMID: 27206371 PMCID: PMC4873992 DOI: 10.1186/s13071-016-1579-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/09/2016] [Indexed: 11/10/2022] Open
Abstract
Background The Gulf Coast tick (Amblyomma maculatum) is an arthropod vector of Rickettsia parkeri, the causative agent of American boutonneuse fever and an infectious agent of public health significance. In this study, we evaluated the biological significance of the superoxide dismutases (SODs) of A. maculatum in hematophagy and R. parkeri colonization within the tick host. Methods An RNA interference approach was used to measure the functional roles of tick SODs (Cu/Zn-SOD and Mn-SOD) in R. parkeri colonization of the tick vector. Total microbial load, R. parkeri infection rate, and compensatory mechanisms by tick genes were examined using quantitative polymerase chain reaction (PCR) and quantitative reverse-transcriptase PCR assays. SOD enzymatic activity assays and malondialdehyde (MDA) lipid peroxidation were employed to determine the redox states in the tick tissues. Results Knockdown of the Cu/Zn-SOD gene caused the upregulation of Mn-SOD in transcript levels. Single and dual knockdowns of the SOD genes caused an increase in MDA lipid peroxidation while SOD enzymatic activities did not show a significant change. Mn-SOD knockdown resulted in a substantial increase in the microbial load; however, Cu/Zn-SOD transcript depletion prompted an upsurge in the midgut bacterial load, and significantly decreased the bacterial load in salivary gland tissues. Additionally, Cu/Zn-SOD transcript silencing led to significantly fewer R. parkeri DNA copy numbers in both tick tissues (midguts and salivary glands). Conclusions SOD enzymes play an important function in the regulation of bacterial communities associated with tick vectors and also in the defense mechanisms against the damage caused by reactive oxygen species within the tick. Knockdown experiments increased the levels of total oxidative stress in ticks, revealing the interplay between SOD isozymes that results in the transcriptional regulation of tick antioxidants. Moreover, the tick's Cu/Zn-SOD aids in the colonization of R. parkeri in tick tissues providing evidence of A. maculatum's vectorial success for a spotted fever group rickettsial pathogen. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1579-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gary Crispell
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - Khemraj Budachetri
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - Shahid Karim
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
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25
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Cabezas-Cruz A, Alberdi P, Ayllón N, Valdés JJ, Pierce R, Villar M, de la Fuente J. Anaplasma phagocytophilum increases the levels of histone modifying enzymes to inhibit cell apoptosis and facilitate pathogen infection in the tick vector Ixodes scapularis. Epigenetics 2016; 11:303-19. [PMID: 27019326 DOI: 10.1080/15592294.2016.1163460] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Epigenetic mechanisms have not been characterized in ticks despite their importance as vectors of human and animal diseases worldwide. The objective of this study was to characterize the histones and histone modifying enzymes (HMEs) of the tick vector Ixodes scapularis and their role during Anaplasma phagocytophilum infection. We first identified 5 histones and 34 HMEs in I. scapularis in comparison with similar proteins in model organisms. Then, we used transcriptomic and proteomic data to analyze the mRNA and protein levels of I. scapularis histones and HMEs in response to A. phagocytophilum infection of tick tissues and cultured cells. Finally, selected HMEs were functionally characterized by pharmacological studies in cultured tick cells. The results suggest that A. phagocytophilum manipulates tick cell epigenetics to increase I. scapularis p300/CBP, histone deacetylase, and Sirtuin levels, resulting in an inhibition of cell apoptosis that in turn facilitates pathogen infection and multiplication. These results also suggest that a compensatory mechanism might exist by which A. phagocytophilum manipulates tick HMEs to regulate transcription and apoptosis in a tissue-specific manner to facilitate infection, but preserving tick fitness to guarantee survival of both pathogens and ticks. Our study also indicates that the pathogen manipulates arthropod and vertebrate cell epigenetics in similar ways to inhibit the host response to infection. Epigenetic regulation of tick biological processes is an essential element of the infection by A. phagocytophilum and the study of the mechanisms and principal actors involved is likely to provide clues for the development of anti-tick drugs and vaccines.
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Affiliation(s)
- Alejandro Cabezas-Cruz
- a University Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center d'Infection et d'Immunité de Lille , Lille , France
| | - Pilar Alberdi
- b SaBio. Instituto de Investigación de Recursos Cinegéticos, IREC-CSIC-UCLM-JCCM , Ciudad Real , Spain
| | - Nieves Ayllón
- b SaBio. Instituto de Investigación de Recursos Cinegéticos, IREC-CSIC-UCLM-JCCM , Ciudad Real , Spain
| | - James J Valdés
- c Institute of Parasitology, Biology Center of the Academy of Sciences of the Czech Republic , Branisovska 31, Budweis, České Budějovice , Czech Republic.,d Department of Virology , Veterinary Research Institute , Hudcova 70, Brno , Czech Republic
| | - Raymond Pierce
- a University Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center d'Infection et d'Immunité de Lille , Lille , France
| | - Margarita Villar
- b SaBio. Instituto de Investigación de Recursos Cinegéticos, IREC-CSIC-UCLM-JCCM , Ciudad Real , Spain
| | - José de la Fuente
- b SaBio. Instituto de Investigación de Recursos Cinegéticos, IREC-CSIC-UCLM-JCCM , Ciudad Real , Spain.,e Department of Veterinary Pathobiology , Center for Veterinary Health Sciences, Oklahoma State University , Stillwater , OK , USA
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26
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Chmelař J, Kotál J, Karim S, Kopacek P, Francischetti IMB, Pedra JHF, Kotsyfakis M. Sialomes and Mialomes: A Systems-Biology View of Tick Tissues and Tick-Host Interactions. Trends Parasitol 2015; 32:242-254. [PMID: 26520005 DOI: 10.1016/j.pt.2015.10.002] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 09/24/2015] [Accepted: 10/02/2015] [Indexed: 12/22/2022]
Abstract
Tick saliva facilitates tick feeding and infection of the host. Gene expression analysis of tick salivary glands and other tissues involved in host-pathogen interactions has revealed a wide range of bioactive tick proteins. Transcriptomic analysis has been a milestone in the field and has recently been enhanced by next-generation sequencing (NGS). Furthermore, the application of quantitative proteomics to ticks with unknown genomes has provided deeper insights into the molecular mechanisms underlying tick hematophagy, pathogen transmission, and tick-host-pathogen interactions. We review current knowledge on the transcriptomics and proteomics of tick tissues from a systems-biology perspective and discuss future challenges in the field.
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Affiliation(s)
- Jindřich Chmelař
- Faculty of Science, University of South Bohemia in České Budějovice, Budweis, Czech Republic; Department of Clinical Pathobiochemistry, Technische Universität Dresden, Dresden, Germany
| | - Jan Kotál
- Faculty of Science, University of South Bohemia in České Budějovice, Budweis, Czech Republic; Institute of Parasitology, Biology Center, Czech Academy of Sciences, Budweis, Czech Republic
| | - Shahid Karim
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS, USA
| | - Petr Kopacek
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, Budweis, Czech Republic
| | - Ivo M B Francischetti
- Section of Vector Biology, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Joao H F Pedra
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Michail Kotsyfakis
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, Budweis, Czech Republic.
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27
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Budachetri K, Karim S. An insight into the functional role of thioredoxin reductase, a selenoprotein, in maintaining normal native microbiota in the Gulf Coast tick (Amblyomma maculatum). INSECT MOLECULAR BIOLOGY 2015; 24:570-81. [PMID: 26184979 PMCID: PMC4560682 DOI: 10.1111/imb.12184] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Tick selenoproteins have been associated with antioxidant activity in ticks. Thioredoxin reductase (TrxR), also a selenoprotein, belongs to the pyridine nucleotide-disulphide oxidoreductase family of proteins and is an important antioxidant. Molecular interactions between native microbiota and tick hosts have barely been investigated to date. In this study, we determined the functional role of TrxR in tick feeding and in maintenance of the native microbial community. TrxR transcript levels remained high and microbial load was reduced throughout tick attachment to the vertebrate host. RNA interference (RNAi) showed that depletion of TrxR activity did not interfere with tick haematophagy or phenotype but did reduce the viability of the microbiome within the tick tissues, presumably by perturbing redox homeostasis. The transcriptional activity of various antioxidant genes remained unaffected whereas the antioxidant genes Manganese superoxide dismutase (MnSOD), copper/zinc superoxide dismutase (Cu/Zn SOD) and selenoprotein M (SelM) were significantly down-regulated in salivary glands of the ticks subjected to RNAi. The perturbed TrxR enzymatic activity in the knocked-down tick tissues negatively affected the bacterial load as well. Furthermore, we observed the altered bacterial profiles in TrxR-silenced tick tissues. Taken together, these results indicate an essential functional role for TrxR in maintaining the bacterial community associated with ticks.
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Affiliation(s)
- K Budachetri
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS, USA
| | - S Karim
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS, USA
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28
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Karim S, Ribeiro JMC. An Insight into the Sialome of the Lone Star Tick, Amblyomma americanum, with a Glimpse on Its Time Dependent Gene Expression. PLoS One 2015; 10:e0131292. [PMID: 26131772 PMCID: PMC4489193 DOI: 10.1371/journal.pone.0131292] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 05/11/2015] [Indexed: 11/19/2022] Open
Abstract
Hard ticks feed for several days or weeks on their hosts. Blood feeding is assisted by tick saliva, which is injected in the host skin regularly, alternating with blood ingestion. Tick saliva contains hundreds or thousands of different peptides and other bioactive compounds that assist feeding by inhibiting their hosts’ blood clotting, platelet aggregation, vasoconstriction, as well as pain and itching. Immunomodulatory and antimicrobial peptides are also found in tick saliva. Molecular characterization of tick salivary compounds, or its sialome (from the Greek sialos = saliva), helps identification of possible antigens that might confer anti-tick immunity, as well as identifying novel pharmacologically active compounds. Amblyomma americanum is a major nuisance tick in Eastern and Southern US, being a vector of Theileria and Ehrlichia bacteria to animals and humans. Presently we report an RNAseq study concerning the salivary glands of adult female A. americanum ticks, which involved sequencing of four libraries collected at different times of feeding. A total of 5,792 coding sequences were deduced from the transcriptome assembly, 3,139 of which were publicly deposited, expanding from the previously available 146 salivary sequences found in GenBank. A remarkable time-dependent transcript expression was found, mostly related to secretory products, supporting the idea that ticks may have several “sialomes” that are expressed at different times during feeding. The molecular nature of this sialome switching remains unknown. The hyperlinked spreadsheet containing the deduced coding sequences can be found at http://exon.niaid.nih.gov/transcriptome/Amb_americanum/Ambame-web.xlsx.
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Affiliation(s)
- Shahid Karim
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, United States of America
| | - José M. C. Ribeiro
- Vector Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
- * E-mail:
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29
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Paddock CD, Goddard J. The Evolving Medical and Veterinary Importance of the Gulf Coast tick (Acari: Ixodidae). JOURNAL OF MEDICAL ENTOMOLOGY 2015; 52:230-52. [PMID: 26336308 DOI: 10.1093/jme/tju022] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 12/02/2014] [Indexed: 05/24/2023]
Abstract
Amblyomma maculatum Koch (the Gulf Coast tick) is a three-host, ixodid tick that is distributed throughout much of the southeastern and south-central United States, as well as several countries throughout Central and South America. A considerable amount of scientific literature followed the original description of A. maculatum in 1844; nonetheless, the Gulf Coast tick was not recognized as a vector of any known pathogen of animals or humans for >150 years. It is now identified as the principal vector of Hepatozoon americanum, the agent responsible for American canine hepatozoonosis, and Rickettsia parkeri, the cause of an emerging, eschar-associated spotted fever group rickettsiosis identified throughout much of the Western Hemisphere. Coincident with these discoveries has been recognition that the geographical distribution of A. maculatum in the United States is far more extensive than described 70 yr ago, supporting the idea that range and abundance of certain tick species, particularly those with diverse host preferences, are not fixed in time or space, and may change over relatively short intervals. Renewed interest in the Gulf Coast tick reinforces the notion that the perceived importance of a particular tick species to human or animal health can be relatively fluid, and may shift dramatically with changes in the distribution and abundance of the arthropod, its vertebrate hosts, or the microbial agents that transit among these organisms.
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Affiliation(s)
- Christopher D Paddock
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Building 17, Room 3224, 1600 Clifton Road, Atlanta, GA 30333.
| | - Jerome Goddard
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Box 9775, 100 Old Hwy 12 (Clay Lyle Building), Starkville, MS 39762
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Adamson S, Browning R, Singh P, Nobles S, Villarreal A, Karim S. Transcriptional activation of antioxidants may compensate for selenoprotein deficiencies in Amblyomma maculatum (Acari: Ixodidae) injected with selK- or selM-dsRNA. INSECT MOLECULAR BIOLOGY 2014; 23:497-510. [PMID: 24698418 PMCID: PMC4107163 DOI: 10.1111/imb.12098] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The Gulf-Coast tick, Amblyomma maculatum, possesses an elaborate set of selenoproteins, which prevent the deleterious effects from oxidative stress that would otherwise occur during feeding. In the current work, we examined the role of selenoprotein K (SelK) and selenoprotein M (SelM) in feeding A. maculatum by bioinformatics, transcriptional gene expression, RNA interference and antioxidant assays. The transcriptional expression of SelK did not vary significantly in salivary glands or midguts throughout the bloodmeal. However, there was a 58-fold increase in transcript levels of SelM in tick midguts. Ticks injected with selK-dsRNA or selM-dsRNA did not reveal any observable differences in egg viability but oviposition was reduced. Surprisingly, salivary antioxidant activity was higher in selenoprotein knockouts compared with controls, which is probably the result of compensatory transcriptional expression of genes involved in combating reactive oxygen species. In fact, quantitative real-time PCR data suggest that the transcriptional expression of catalase increased in ticks injected with selM-double-stranded RNA. Additionally, the transcriptional expression of selN decreased ∼90% in both SelK/SelM knockdowns. These data indicate that SelK and SelM are salivary antioxidants but are not essential for tick survival or reproduction and are compensated by other antioxidant systems.
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Affiliation(s)
- S Adamson
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS, USA
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