Short communication: Proteins from circulating exosomes represent metabolic state in transition dairy cows.
Biomarkers that identify prepathological disease could enhance preventive management, improve animal health and productivity, and reduce costs. Circulating extracellular vesicles, particularly exosomes, are considered to be long-distance, intercellular communication systems in human medicine. Exosomes provide tissue-specific messages of functional state and can alter the cellular activity of recipient tissues through their protein and microRNA content. We hypothesized that exosomes circulating in the blood of cows during early lactation would contain proteins representative of the metabolic state of important tissues, such as liver, which play integral roles in regulating the physiology of cows postpartum. From a total of 150 cows of known metabolic phenotype, 10 cows were selected with high (n=5; high risk) and low (n=5; low risk) concentrations of nonesterified fatty acids, β-hydroxybutyrate, and liver triacylglycerol during wk 1 and 2 after calving. Exosomes were extracted from blood on the day of calving (d 0) and postcalving at wk 1 and wk 4, and their protein composition was determined by mass spectroscopy. Extracellular vesicle protein concentration and the number of exosome vesicles were not affected by risk category; however, the exosome protein cargo differed between the groups, with proteins at each time point identified as being unique to the high- and low-risk groups. The proteins α-2 macroglobulin, fibrinogen, and oncoprotein-induced transcript 3 were unique to the high-risk cows on d 0 and have been associated with metabolic syndrome and liver function in humans. Their presence may indicate a more severe inflammatory state and a greater degree of liver dysfunction in the high-risk cows than in the low-risk cows, consistent with the high-risk cows' greater plasma β-hydroxybutyrate and liver triacylglycerol concentrations. The commonly shared proteins and those unique to the low-risk category indicate a role for exosomes in immune function. The data provide preliminary evidence of a potential role for exosomes in the immune function in transition dairy cows and exosomal protein cargo as biomarkers of metabolic state.
DairyNZ, 3A Symonds Street, Auckland 1010, New Zealand. Electronic address: mallory.crookenden@dairynz.co.nz.
M A
MA
Crookenden
DairyNZ, 3A Symonds Street, Auckland 1010, New Zealand.
C G
CG
Walker
University of Queensland, Centre for Clinical Research, Herston, Queensland 4029, Australia.
H
H
Peiris
University of Queensland, Centre for Clinical Research, Herston, Queensland 4029, Australia.
Y
Y
Koh
Institute of Vet, Animal and Biomedical Sciences, Massey University, Palmerston North 4442, New Zealand; AgResearch, Hopkirk Research Institute, Palmerston North 4442, New Zealand.
A
A
Heiser
Department of Animal Sciences, University of Illinois, Urbana 61801.
J J
JJ
Loor
Department of Animal and Avian Sciences, University of Maryland, College Park 20742.
K M
KM
Moyes
Institute of Vet, Animal and Biomedical Sciences, Massey University, Palmerston North 4442, New Zealand.
A
A
Murray
Institute of Vet, Animal and Biomedical Sciences, Massey University, Palmerston North 4442, New Zealand.
V S R
VSR
Dukkipati
DairyNZ, Cnr Ruakura & Morrinsville Rds (SH26), Newstead, Hamilton 3284, New Zealand.
J K
JK
Kay
DairyNZ, Cnr Ruakura & Morrinsville Rds (SH26), Newstead, Hamilton 3284, New Zealand.
S
S
Meier
DairyNZ, Cnr Ruakura & Morrinsville Rds (SH26), Newstead, Hamilton 3284, New Zealand.
J R
JR
Roche
University of Queensland, Centre for Clinical Research, Herston, Queensland 4029, Australia.
M D
MD
Mitchell
D020155:3-Hydroxybutyric Acid / Q000097:blood*; D000818:Animals; D002417:Cattle / Q000502:physiology*; D055354:Exosomes / Q000502:physiology*; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D007774:Lactation; D008099:Liver / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism*
D005230:Fatty Acids, Nonesterified; D014280:Triglycerides; D020155:3-Hydroxybutyric Acid
exosome; lactation extracellular vesicle; metabolic state