Time-resolved proteomic profile ofAmblyomma americanumtick saliva during feeding

Abstract

24Amblyomma americanum ticks transmit more than a third of human tick-borne disease 25 (TBD) agents in the United States. Tick saliva proteins are critical to success of ticks as vectors 26 of TBD agents, and thus might serve as targets in tick antigen-based vaccines to prevent TBD 27 infections. We describe a systems biology approach to identify, by LC-MS/MS, saliva proteins 28 (tick=1182, rabbit=335) that A. americanum ticks likely inject into the host every 24 h during the 29 first 8 days of feeding, and towards the end of feeding using two different sample preparation 30 approaches (in-gel and in-solution). The in-gel approach determined molecular identification of 31 predominant protein bands in tick saliva, and the in-solution added depth to discovery of 32 proteins. Searching against entries in GenBank grouped tick and rabbit proteins in this study into 33 27 and 25 functional categories. Aside from housekeeping-like proteins, majority of tick saliva 34 proteins belong to the tick-specific (no homology to non-tick organisms: 32%), protease 35 inhibitors (13%), proteases (8%), glycine-rich proteins (6%) and lipocalins (4%) categories.36 Global secretion dynamics analysis suggests that majority (74%) of proteins in this study are 37 associated with regulating initial tick feeding functions and transmission of pathogens as they are 38 secreted within 24-48 h of tick attachment. Comparative analysis of the A. americanum tick 39 saliva proteome to five other tick saliva proteomes identified 284 conserved tick saliva proteins:40 we speculate that these regulate critical tick feeding functions and might serve as tick vaccine 41 antigens. We discuss our findings in the context of understanding A. americanum tick feeding 42 physiology as a means through which we can find effective targets for a vaccine against tick 43 feeding. 44 45 3 46 Author Summary 47The lone star tick, Amblyomma americanum, is a medically important species in US that 48 transmits 5 of the 16 reported tick-borne disease agents. Most recently, bites of this tick were 49 associated with red meat allergies in humans. Vaccination of animals against tick feeding has 50 been shown to be a sustainable and effective alternative to current acaricide based tick control 51 method which has several limitations. The pre-requisite to tick vaccine development is to 52 understand the molecular basis of tick feeding physiology. Toward this goal, this study has 53 identified proteins that A. americanum ticks inject into the host at different phases of its feeding 54 cycle. This data set has identified proteins that A. americanum inject into the host within 24-48 h 55 of feeding before it starts to transmit pathogens. Of high importance, we identified 284 proteins 56 that are present in saliva of other tick species, which we suspect regulate important role(s) in tick 57 feeding success and might represent rich source target antigens for a tick vaccine. Overall, this 58 study provides a foundation to understand the molecular mechanisms regulating tick feeding 59 p...

Failed Disruption of Tick Feeding, Viability, and Molting after Immunization of Mice and Sheep with Recombinant Ixodes ricinus Salivary Proteins IrSPI and IrLip1

“…Indeed, it would have been interesting to test the impact of vaccination on female engorgement, as they feed over a long period of time, leading to greater exposure to antibodies. It is also known that the protein profile and abundance in tick salivary glands and saliva is dynamic during the course of tick feeding, as has been demonstrated for several tick species [ 49 , 50 , 51 , 52 ], and as we have previously confirmed for IrSPI [ 31 ]. Thus, it is possible that IrSPI and IrLip1 are not highly expressed during feeding by larvae and nymphs and/or do not make a significant positive contribution to tick engorgement and viability during these stages, which would render them less than ideal as vaccine candidates.…”

“…Thus, it is possible that IrSPI and IrLip1 are not highly expressed during feeding by larvae and nymphs and/or do not make a significant positive contribution to tick engorgement and viability during these stages, which would render them less than ideal as vaccine candidates. In future studies, it would be useful to include early onset and long-term expression during feeding as criteria for the selection of salivary vaccine candidates, as was done by Kim and co-workers for the tick I. scapularis [ 50 ] and more recently for Amblyomma americanum [ 51 ]. Such a strategy would permit the selection of proteins that are highly expressed at the beginning of the feeding step, preceding TBP transmission.…”

Quantitative Visions of Reality at the Tick-Host Interface: Biochemistry, Genomics, Proteomics, and Transcriptomics as Measures of Complete Inventories of the Tick Sialoverse

“…The authors indicate that protein profiles change over the course of feeding and suggest that this switching mechanism is used as immune evasion strategy. More recently, the saliva profile of A. americanum was determined using the in situ digestion, LC-MS/MS approach (Kim et al, 2020 ). Saliva was collected from ticks attached for 24, 48, 72, 96, 120, 144, 168, and 192 h, as well as engorged and detached.…”

“…To this end, raw proteomic data can be submitted to the PRoteomics IDEntification database (PRIDE) (Perez-Riverol et al, 2019 ). To this end, proteomic data for at least 6 tick species is available in PRIDE and include A. americanum (Crispell et al, 2019 ; Kim et al, 2020 ), A. sculptum (Esteves et al, 2017 ), I. scapularis (Villar et al, 2015 ; Kim et al, 2016 ), I. ricinus (Cramaro et al, 2015 ), H. longicornis (Ren et al, 2019 ), and R. sanguineus (Tirloni et al, 2020 ).…”

Mechanisms Affecting the Acquisition, Persistence and Transmission of Francisella tularensis in Ticks

“…Conversely, depletion of varisin from D. variabilis ticks reduced Anaplasma marginale infections, suggesting that the true role of defensins in tick–pathogen interactions may be complex [ 134 , 135 ]. A recent proteomic analysis of A. americanum tick proteins produced during a blood meal indicates that this tick species produces at least six antimicrobial peptides, including kunitz-type serine proteinase inhibitor, lipochalin, microplusin, lysozyme, and defensins [ 136 ]. Many other potential tick immune molecules, such as fibrinogen-related proteins (FREPs) and thioester-containing proteins (TEPs), have been identified in soft and hard ticks and have been proposed to play important roles in protecting ticks from microbial infections [ 114 , 115 , 116 ].…”