Physicochemical Biomolecular Insights into Buffalo Milk-Derived Nanovesicles

Abstract

Milk is a natural nutraceutical produced by mammals. The nanovesicles of milk play a role in horizontal gene transfer and confer health-benefits to milk consumers. These nanovesicles contain miRNA, mRNA, and proteins which mediate the intercellular communication. In this work, we isolated and characterized the buffalo milk-derived nanovesicles by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), scanning electron microscopy (SEM), Western probing, and Fourier transform infrared (FTIR) spectroscopy. The DLS data suggested a bimodal size distribution with one mode near 50 nm and the other around 200 nm for the nanovesicles. The NTA and SEM data also supported the size of nanovesicles within a range of 50-200 nm. The FTIR measurements of nanovesicles identified some prominent absorption bands attributable to the proteins (1300-1700 cm(-1), amide A and amide B bands), lipids (2800-3100 cm(-1)), polysaccharides, and nucleic acids (900-1200 cm(-1)). The comparative expression profiles of immune miRNA signatures (miR-15b, miR-21, miR-27b, miR-125b, miR-155, and miR-500) in nanovesicles isolated from milk, serum, and urine revealed that these miRNAs are present abundantly (P< 0.05) in milk-derived nanovesicles. Milk miRNAs (miR-21 and 500) that were also found stable under different household storage conditions indicated that these could be biologically available to milk consumers. Overall, nanovesicles are a new class of bioactive compounds from buffalo milk with high proportion of stable immune miRNAs compared to urine and plasma of same animals.

Milk MicroRNAs in Health and Disease

“…To achieve comparable resistance without 2'O-methylation, milk microRNAs are protected by their binding to Ago2 and encapsulation by the EV bilayer membrane (Baddela et al, 2016;Benmoussa et al, 2016Benmoussa et al, , 2017Benmoussa et al, , 2018Blans et al, 2017;Chen et al, 2014). Such mechanism would further differentiate milk from other biological fluids, like plasma, where only 1% to 5% of extracellular microRNAs are encapsulated in vesicles (Tome-Carneiro et al, 2018).…”

Milk’s Role as an Epigenetic Regulator in Health and Disease

“…In 2007, immune-regulatory exosomes from human colostrum and mature human milk have been isolated and characterized for the first time [36]. In the meantime, milk-derived exosomes have been detected in colostrum and mature milk of humans, cows, buffalos, goats, pigs, marsupial tammar wallabies and rodents [36,37,38,39,40,41,42,43,44,45,46,47,48]. Milk miRNAs have been detected in both the fat fraction of milk and skimmed milk [17,49,50].…”

“…In contrast, effects of cold storage and somatic cell content were quantitatively minor (<2% loss) [63]. Buffalo milk miRNA-21 and miRNA-500 were found stable under different household storage conditions indicating that these could be biologically available to milk consumers [48]. Heating in the microwave caused a 40% loss of miRNA-29b but no loss of miRNA-200c [63].…”

“…Cow’s milk is a rich source of exosomal miRNA-21 [37,48]. It has been demonstrated that miRNA-21 acts as a bidirectional switch in the formation of insulin-producing cells by regulating the expression of target and downstream genes (SOX6, RPBJ and HES1) [310].…”

Bioactive components derived from bovine milk

“…miRNA shows a specific stability when present in milk, and its main and most important property is the resistance to unfavourable environmental conditions such as boiling, low pH, freezing or thawing up. The reason for such stability in the extreme environmental conditions is most probably the protective role of a lipid bilayer that is covering miRNAs (Baddela et al, 2016). Since miRNAs is resistant to low pH, it can easily pass through the gastrointestinal tract without degradation and thus it can affect the processes in the body.…”