Identification and characterization of microRNAs in raw milk during different periods of lactation, commercial fluid, and powdered milk products

Abstract

Recent baby formula milk powder contamination incidents have shown that the classic markers or standards in milk quality control are insufficient in identifying "manipulated" poor-quality milk. In the present study, we demonstrated for the first time that cow milk contains large amounts of microRNAs (miRNAs) and that the unique expression profile of milk-specific miRNAs can serve as a novel indicator and possible new standard for the quality control of raw milk and milk-related commercial products, such as fluid milk and powdered formula milk. First, using Solexa sequencing, we systematically screened miRNA expression in raw milk and identified a total of 245 miRNAs in raw milk. Unlike other classic biomarkers whose expression levels are nearly identical at different periods of lactation, individual miRNAs can be significantly altered during lactation process, implicating that miRNAs may be a more accurate indicator to reflect the quality alteration of milk. Second, using TaqMan probe-based miRNA quantitative RT-PCR, we further identified seven miRNAs that have a relatively consistent expression throughout the lactation process, and more importantly, the expression profile of these seven milk-specific miRNAs can serve as an ideal biomarker for discriminating poor-quality or "manipulated" milk from pure raw milk, as well as for the quality control of commercial milk products, such as fluid milk and powdered formula milk. Together, our findings provide a basis for understanding the physiological role of milk miRNAs and a new potential standard for determining the quality of raw milk or milk-related commercial products.

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

“…Various types of miRNAs were detected in body fluids, including blood, urine, saliva, and milk (Weber et al, 2010). Milk, a primary nutrition source for infants and a widely used food, contains more than 400 miRNAs (Chen et al, 2010;Zhou et al, 2012). The constitution of miRNAs in milk varies among different species (Hata et al, 2010;Munch et al, 2013;Izumi et al, 2014), the lactation period (Chen et al, 2010), and maternal dietary manipulation (Hata et al, 2010).…”

“…Milk, a primary nutrition source for infants and a widely used food, contains more than 400 miRNAs (Chen et al, 2010;Zhou et al, 2012). The constitution of miRNAs in milk varies among different species (Hata et al, 2010;Munch et al, 2013;Izumi et al, 2014), the lactation period (Chen et al, 2010), and maternal dietary manipulation (Hata et al, 2010). Moreover, some miRNAs that are abundant in milk have been evidenced for their important functional roles in various biological processes, including immune response (Kosaka et al, 2010;Sun et al, 2013), postnatal growth (Melnik et al, 2013), and lipid metabolism (Fernández-Hernando et al, 2011).…”

MicroRNAs in tomato plants

“…MiRNAs can also serve as an ideal biomarker for discriminating poor-quality or 'manipulated' milk from pure raw milk, as well as for quality control of commercial milk products, such as fluid milk and powdered formula milk [50]. However, use of plant miRNAs as biomarkers of disease is still at an exploratory stage.…”