Dataset Information

Proteomics study of Amblyomma variegatum saliva, characterization of the molecular determinants.

ABSTRACT: Amblyomma variegatum, the tropical bont tick, is a species of veterinary importance being considered as one of major pest of ruminants in Africa and in the Caribbean. It is associated with severe dermatophilosis and transmits the rickettsiale Ehrlichia ruminantium, the agent of heartwater, to ruminants. Tick’s saliva contains a complex mixture of bioactive molecules including proteins that modulate host responses to ensure successful blood feeding. The limited amount of saliva that can be obtained from ticks has hampered characterisation of salivary proteins using traditional protein chemistry, but recent advances in proteomics (especially mass spectrometry and bioinformatics) provide new tools to finely investigate tick sialomes. The general objective of this study was to better understand the role of A. variegatum saliva in tick/host/pathogen interactions. Salivation of semi-fed females was induced after detachment by injection of pilocarpin. Crude saliva proteins were pre-fractioned by SDS-PAGE and trypsin-generated peptides were analysed online by nano-flow Ultimate 3000 HPLC–nanoelectrospray ionization using an Orbitrap Elite mass spectrometer. Raw data analysis was performed using the MaxQuant software and proteins identified according to UniProt Knowledgebase. Our results bring new insights for a better understanding of tick-ruminant interactions at the molecular level, and pave the way towards integrative strategies to interfere with both the immunomosuppressive and infectious processes in corresponding tick-borne diseases.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Ixodes Scapularis (black-legged Tick) (deer Tick) Amblyomma

TISSUE(S): Saliva

SUBMITTER: Oana Vigy

LAB HEAD: Philippe Holzmuller

PROVIDER: PXD007821 | Pride | 2018-01-05

REPOSITORIES: Pride

ACCESS DATA

Dataset's files

Source:

			Action	DRS
	MaxQuant_txt.zip	Other
	Proteome_iscapularis-iso_2015_03.fasta	Fasta
	SAMVA_150305_114_E_A.raw	Raw
	SAMVA_150305_114_E_B.raw	Raw
	SAMVA_150305_114_E_C.raw	Raw

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Publications

Immunomodulatory Effects of <i>Amblyomma variegatum</i> Saliva on Bovine Cells: Characterization of Cellular Responses and Identification of Molecular Determinants.

Rodrigues Valérie V Fernandez Bernard B Vercoutere Arthur A Chamayou Léo L Andersen Alexandre A Vigy Oana O Demettre Edith E Seveno Martial M Aprelon Rosalie R Giraud-Girard Ken K Stachurski Frédéric F Loire Etienne E Vachiéry Nathalie N Holzmuller Philippe P

Frontiers in cellular and infection microbiology 20180104

The tropical bont tick, <i>Amblyomma variegatum</i>, is a tick species of veterinary importance and is considered as one of major pest of ruminants in Africa and in the Caribbean. It causes direct skin lesions, transmits heartwater, and reactivates bovine dermatophilosis. Tick saliva is reported to affect overall host responses through immunomodulatory and anti-inflammatory molecules, among other bioactive molecules. The general objective of this study was to better understand the role of saliva ...[more]

PMID: 29354598

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Project description:Ticks are obligate blood feeding ectoparasites that transmit a wide variety of pathogenic microorganisms to their vertebrate hosts. Amblyomma sculptum is vector of Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, the most lethal rickettsiosis that affects humans. It is known that the transmission of pathogens by ticks is mainly associated with the physiology of the feeding process. Pathogens that are acquired with the blood meal must first colonize the tick gut and later the salivary glands in order to be transmitted during a subsequent blood feeding via saliva. Tick saliva contains a complex mixture of bioactive molecules with anticlotting, antiplatelet aggregation, vasodilatory, anti-inflammatory, and immunomodulatory properties to counteract both the hemostasis and defense mechanisms of the host. Besides facilitating tick feeding, the properties of saliva may also benefits survival and establishment of pathogens in the host. In the current study, we compared the sialotranscriptome of unfed A. sculptum ticks and those fed for 72 h on rabbits using next generation RNA sequencing (RNA-seq). The total of reads obtained were assembled in 9,560 coding sequences (CDSs) distributed in different functional classes. CDSs encoding secreted proteins, including lipocalins, mucins, protease inhibitors, glycine-rich proteins, metalloproteases, 8.9 kDa superfamily members, and immunity-related proteins were mostly upregulated by blood feeding. Selected CDSs were analyzed by real-time quantitative polymerase chain reaction preceded by reverse transcription (RT-qPCR), corroborating the transcriptional profile obtained by RNA-seq. Finally, high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis revealed 124 proteins in saliva of ticks fed for 96-120 h. The corresponding CDSs of 59 of these proteins were upregulated in salivary glands of fed ticks. To the best of our knowledge, this is the first report on the proteome of A. sculptum saliva. The functional characterization of the identified proteins might reveal potential targets to develop vaccines for tick control and/or blocking of R. rickettsii transmission as well as pharmacological bioproducts with antihemostatic, anti-inflammatory and antibacterial activities.

Project description:Tick saliva contains many bioactive molecules that are involved in attachment to the host, blood feeding and transmission of pathogens. MicroRNAs (miRNAs) are a class of short non-coding RNAs with a length of 19-24 nucleotides. They act as regulators of gene expression by binding to their target mRNA at the post-transcriptional level and control a variety of cellular functions, including regulation of growth, metabolism, and development. The detection and characterizations of miRNAs from tick saliva may help explain the molecular mechanisms involved in the interaction between ticks, pathogens, and hosts. They may also contribute to the discovery of vaccines, which can control ticks and the pathogens they transmit. An RNA library was generated from the saliva of fed adult Haemaphysalis longicornis ticks, and it contained 17.4 million clean reads of 18-30 nucleotides. Overall, 319 known miRNAs and 1 novel miRNA were found. The 10 most abundantly expressed miRNAs present in tick saliva were miR-100_2, miR-315, miR-184_1, miR-100-5p_2, miR-5307, miR-184-3p_3, Let-7-5p_6, miR-71_5, miR-1-3p_6, and miR-10-5p_2. The miR-375, one of the abundantly expressed, was subjected to Quantitative Real-Time PCR analysis (qRT-PCR) in various tick developmental stages, as well as in different tissues isolated from adult ticks. The expression of miR-375 in different tick development stages was highest in unfed nymphs and lowest in the egg stage. In the tissues of adult ticks, miR-375 was most highly expressed in the salivary gland. To investigate the possible role of miR-375, Ant-375 was used to inhibit the miR-375. Treated group (Ant-375) had a reduced number of eggs (t(10)= 2.652, P=0.0242), eggs that were partially desiccated, and reduced egg hatchability (t(10)=2.272, P=0.044) compared to Ms-Ant and the non-injected control. This is the first study to investigate the miRNAs profile in tick saliva and the role of miR-375 in H. longicornis. The identification and characterization of miRNA in tick saliva may help to reveal the molecular mechanisms of interactions among ticks, pathogens, and hosts and suggest new vaccine strategies to control tick borne diseases.