Poster Presentation Australasian Extracellular Vesicles Conference 2018

Circulating exosome content of beef cattle resistant and non-resistant to cattle tick. (#72)

Hassendrini N Peiris 1 , Nick Cameron 2 , Nathanael McGhee 2 , Michael McGowan 3 , Ala Tabor 4 , Joseph Olm 3 , Constantin Constantinoiu 5 , Russell Lyons 6 , Kanchan Vaswani 1 , Murray D Mitchell 1
  1. Queensland University of Technology, South Brisbane, QLD, Australia
  2. Nindooinbah Pastoral Company, Beaudesert, QLD, Australia
  3. School of Veterinary Science, The University of Queensland,, Brisbane, QLD, Australia
  4. Queensland Alliance for Agriculture and Food Innovation, The University of Queensland,, Brisbane, QLD, Australia
  5. School of Veterinary and Biomedical Sciences, James Cook University, Townsville, QLD, Australia
  6. Animal Genetics Laboratory , The University of Queensland,, Brisbane, QLD, Australia

Introduction: Cattle ticks costs the Australian cattle industry $160 million annually. Increased acaricide resistance by ticks and chemical residues remaining in meat, milk and the environment underline the need for the effective identification of tick resistant cattle. We hypothesise exosomal content will differ between cattle resistant and non-resistant to cattle ticks.

Methods: The hind regions, belly and neck of cattle were assessed for cattle ticks and a score of 1 to 5 (1=none, 2=< 10, 3= 20 to 100, 4= 100 to 200, 5= > 200 ticks) assigned. Blood was collected in EDTA vacutainer tubes. Exosomes were isolated from plasma of cattle scoring 1 (low tick group) or greater than 4 (high tick group) using ultracentrifugation combined with size exclusion chromatography. Exosomes were confirmed by nanoparticle tracking analyses (size), transmission electron microscopy (morphology) and immunoblotting (e.g. Flotillin-1). Proteomic profiling was conducted on 10ug of exosomal protein (following reduction, alkylation, and digestion) by Mass Spectrometry (LC-MS/MS).

Results: The cattle scoring a 1 on the cattle tick scale made up 45% and those with a score of 4 or greater were 14% of the total cattle population. Proteomic analysis identified 33 proteins unique to the high tick group, 17 proteins unique to the low tick group (e.g. thioredoxin reductase 1) and 76 common to both groups.

Conclusion: In depth evaluations of the proteins identified within the exosomes as well as other cargo e.g. miRNA may enable the identification and selection of tick resistant cattle and significantly benefiting the cattle industry.