Project description:Mastitis, the inflammation of the mammary gland, is one of the most prevalent diseases in dairy farming worldwide. Unfortunately, the disease is most often present in a subclinical type with no clear symptoms. The sooner the infection is detected, the less opportunities for the disease to progress and the more treatment options remain available. Milk microRNA (miRNA) encapsulated in extracellular vesicles (EV) have been proposed as potential biomarkers of different mammary gland conditions, including subclinical mastitis. However, little is known about the robustness of EV analysis regarding sampling time-point or natural infections. In order to estimate the reliability of EV measurements in raw bovine milk, we first evaluated the changes in EV size, concentration and miRNA cargo during three consecutive days. Then, we compared milk EV differences from natural infected quarters with high somatic cell count (SCC) with their healthy adjacent quarters with low SCC and quarters from uninfected udders. We found that milk EV miRNA cargo is very stable along three days and that infected quarters do not induce relevant changes in milk EV of adjacent healthy quarters, making them suitable controls. We observed cow-individual changes in immunoregulatory miRNA in quarters with chronic subclinical mastitis, pointing towards infection-specific alterations. Finally, we proposed bta-miR-223 as a potential indicator of subclinical mastitis prognosis in raw milk.
Project description:We report the application of miRNA next generation sequencing (NGS) for the analysis of impact of processing on miRNA in human breast milk, donated by 3 volunteers. MiRNA content of total and exosomal fraction was compared between unprocessed milk and sample subjected to either Holder (thermal) pasteurization (HoP) or elevated pressure processing (HPP). NGS reads were mapped to miRBase in order to obtain miRNA counts. Then, we analyzed differences in the miRNA abundance and function between raw and processed material. It was observed that both processing methods reduce number of miRNA reads and HoP is significantly more detrimental to miRNA than HPP.