Urinary Proteome of Newborn Calves-New Potential in Non-Invasive Neonatal Diagnostic.

Abstract

Simple SummaryUrine is an underappreciated biological sample in the context of health monitoring of newborn calves. It can be collected noninvasively and used for diagnostic purposes, which is an attractive option in veterinary examination. The establishment of urinary protein maps of healthy newborn calves is important for diagnosing and monitoring the progression of various diseases. The aim of this study was to characterize the urinary proteome profile of healthy newborn calves. We applied 2-D gel electrophoresis combined with MALDI-TOF-TOF-MS/MS and 1-D gel electrophoresis coupled with LC-MS-MS analysis to separate and identify proteins present in the urine of newborn calves. Urinary proteomic analysis allowed us to detect proteins which are characteristic of embryonic and neonatal development and proteins involved in the cardiovascular and digestive system, and bone and kidney development. Moreover, we identified proteins that can be used to assess normal glomerular and tubular physiology. In calves, one of the main causes of mortality in the neonatal period is diarrhea, affecting fluid and electrolyte balance. We also identified proteins involved in the renal transport of water and electrolytes, which can be useful in the early diagnosis and prevention of these type of disorders. Urine is a biological diagnostic material suitable not only for the analysis of kidney and urinary tract functions but also the function of other tissues and organs. The urine proteome of adult mammals differs from the urine proteome of neonatal ones. The establishment of urinary protein maps of healthy newborn calves is important for diagnosing and monitoring the progression of various diseases. The experiment was carried out on a Polish-Friesian var. of Black-and-White male calves in the sixth day of postnatal life. The two proteomics approaches used for separation and identification of urinary proteins were: 2-DE with MALDI-TOF-TOF-MS/MS and 1-DE with LC-MS/MS. This resulted in the identification of 692 urinary proteins. The majority of them were classified as extracellular proteins (40.32%), as well as proteins involved in regulation of major cellular processes (31.07%). We have observed the presence of unique proteins associated with embryonic (ameloblastin, alpha-fetoprotein, Delta-like protein, embryo-specific fibronectin 1 transcript variant, Indian hedgehog homolog) and kidney development (angiotensin-converting enzyme, angiotensinogen, aquaporin-1, calbindin, glypican 3, nidogen 1, pro-cathepsin H). Additionally, proteins involved in the renal regulation of water and electrolyte balance (angiotensinogen, angiotensin-converting enzyme, aquaporin-1, ezrin, uromodulin) were detected. Presented in the current study 1-D and 2-D urinary proteomic maps are the basis for the identification and detection of prognostic biomarkers important for defining a calf’s health status.