Bovine milk contains microRNA and messenger RNA that are stable under degradative conditions

Abstract

We previously reported that microRNA (miRNA) is present in human breast milk. Recently, other groups have reported that bovine milk also contains miRNA; however, these reports are few. We therefore investigated bovine milk miRNA using microarray and quantitative PCR analyses to identify the differences between colostrum and mature milk. The RNA concentration in a colostrum whey fraction was higher than that in a mature milk whey fraction. In total, 102 miRNA were detected in bovine milk by microarray analysis (100 in colostrum and 53 in mature milk; 51 were common to both). Among these miRNA, we selected several immune- and development-related miRNA, including miR-15b, miR-27b, miR-34a, miR-106b, miR-130a, miR-155, and miR-223. These miRNA were detected in bovine milk by quantitative PCR, and each of these miRNA was significantly more highly expressed in colostrum than in mature milk. We also confirmed the presence of some mRNA in bovine milk. Nevertheless, synthesized miRNA spiked in the raw milk whey were degraded, and naturally existing miRNA and mRNA in raw milk were resistant to acidic conditions and RNase treatment. The RNA molecules in milk were stable. We also detected miRNA and mRNA in infant formulas purchased from Japanese markets. It is still unknown whether milk-derived RNA molecules play biological roles in infants; however, if milk-derived RNA do show functions in infants, our data will help guide future studies.

Biocompatibility of highly purified bovine milk‐derived extracellular vesicles

“…Similarly, mEVs from bovine milk were isolated and characterized [13]. Our group demonstrated that bovine mEV contains mRNA and miRNA [14]; thus, mEVs may deliver these RNAs to recipient cells [15]. …”

The clinical significance of platelet microparticle-associated microRNAs

“…While the majority of microRNAs are found and mediate their regulatory effects on gene expression intracellularly, a number of microRNAs are also present in the extracellular milieu and in various biological fluids of the human body, such as maternal milk [34][35][36][37][38], saliva [39,40], urine [41], nasal secretions [42,43], sperm [44] and plasma [45][46][47][48], and may represent interesting biomarkers of diseases [49,50].…”

Comparative studies of two methods for miRNA isolation from milk whey

“…Milk was collected from 24 multiparous cows at approximately 150 d in milk with diethylpyrocarbonate (DEPC)-treated tubes, stored at −20 °C immediately after collection, transferred to the laboratory within 2 h, and stored at −80 °C until further use. Milk pre-preparation procedures were performed according to Izumi et al (2012)'s protocol with some modifications. Briefly, samples were centrifuged twice (1200×g, 4 °C, 10 min), syringed into the middle defatted layer under RNase-free conditions, and dispensed into 1 ml aliquots per tube.…”

“…In the studies describing RNA extraction from cell-free fluids, such as milk whey, two alternative RNA extraction methods have already been performed, i.e. the phenol-based technique (Chen et al, 2010) and column-based approach (Trizol followed by cleanup using the modified RNeasy, miRNeasy or mirVana kit) (Izumi et al, 2012). Despite some discrepancies between these two isolation methods in other body fluid samples (McAlexander et al, 2013;Moret et al, 2013;Duy et al, 2015), none of these studies compared and evaluated the quantity and quality of the isolated miRNAs from milk using these two methods.…”