E-Poster Presentation ESA-SRB-ANZBMS 2021

Blood plasma-derived small extracellular vesicles as markers of immune dysregulation in cattle: a tool for improving reproductive outcomes (#517)

Natalie Turner 1 , Pevindu Abeysinghe 1 , Hassendrini Peiris 1 , Kanchan Vaswani 1 , Nick Cameron 2 , Nathanael McGhee 2 , Pawel Sadowski 3 , Murray D Mitchell 1 , Jayden Logan 1
  1. Centre for Children’s Health Research, School of Biomedical Sciences, Faculty of Health, The Queensland University of Technology, Brisbane, Queensland, 4029, Australia.
  2. Nindooinbah, 272, Nindooinbah House Road, Beaudesert, 4285
  3. Central Analytical Research Facility (CARF), QUT Gardens Point Campus, 2 George St, Brisbane City, QLD 4000

Background: Cattle fertility has been in decline for the past 20 years. Small extracellular vesicles (sEVs) are cell-secreted nanoparticles (~30 – 150 nm diameter) present in biofluids such as blood plasma and have been used as biomarkers of health and disease. As essential players in cell-cell signalling and communication, sEVs provide a systemic snapshot of the overall health state of the animal. Immune dysregulation is associated with poor reproductive outcomes in cattle; therefore, our lab has investigated whether proteomic analysis of circulating (blood plasma-derived) sEVs by mass spectrometry (MS) is a valid tool for profiling cattle with known immune diversity due to tick burden.

Methods: Blood was collected into evacuated EDTA blood tubes from cattle with low (>200 ticks) or high tick resistance (no identifiable ticks) (n = 3/group). sEVs were isolated from blood plasma by sequential centrifugation and size exclusion chromatography using an established method of sEV isolation. sEV and non-sEV containing fractions were pooled separately and subjected to validation experiments prior to being processed for MS analysis operated in data-dependent acquisition mode. Data were processed using Protein Pilot and filtered using 1% false discovery rate (FDR) cut-off at the protein level, and 5% FDR at the peptide level, with minimum 2 peptides per protein. PANTHERGO online software tool was utilised for gene ontology analysis from the final protein list.

Results: A total of 490 unique sEV proteins were identified. Of the 30 proteins unique to high tick-resistant cattle, defense/immunity proteins accounted for 50% of these, however this protein class was not detected in low tick-resistant animals.

Conclusions: Proteome profiling of circulating sEVs is a valid tool for assessing immune status in cattle. Blood plasma-derived sEV profiling may be of use in determining cattle at-risk of immune dysfunction around the time of calving with the aim of improving reproductive outcomes.

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