Milk-Derived Extracellular Vesicles Suppress Inflammatory Cytokine Expression and Nuclear Factor-κB Activation in Lipopolysaccharide-Stimulated Macrophages

Susanne R Ascanius,Marie S Ostenfeld,Jan T Rasmussen,Maria S Hansen

doi:10.3390/dairy2020015

Abstract

In milk and milk products, small membrane-enclosed vesicles can be found, commonly termed extracellular vesicles (EVs). Milk-derived EVs have previously been suggested to have immunoregulatory properties, especially important for infants without a fully functioning immune system. In the present study, EV fractions were isolated from human milk, mature and colostrum bovine milk, and two dairy fractions, and successively surveyed for their immunomodulating effects on lipopolysaccharide (LPS)-stimulated macrophages (RAW264.7). RAW264.7 cell material and supernatant were evaluated by monitoring degradation of IκBα in the NF-κB pathway, and IL-6 and IL-1β cytokine production, using Western blotting and enzyme-linked immunosorbent assaying, respectively. The results revealed that preincubation with EVs derived from raw human and bovine milk lowered the LPS-activated response of the NF-κB pathway. Additionally, it was found that preincubation with EVs, from human and bovine milk as well as dairy whey or skim milk-derived fractions, decreased secretion of proinflammatory cytokines from LPS-activated RAW264.7 cells. The findings that milk-derived EVs can change the inflammatory response in macrophages support the notion that milk EVs have an important role in mother-to-infant communication and protection of a newborn.

Highlights

IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
MiRNAs found in bovine EVs (bEV), like miR-141 or miR-155, have been shown to downregulate the production of proinflammatory cytokines, by suppressing the activation of the NF-κB leading to a decreased level of inflammation in the intestine [46,47,48]. These studies, together with the results presented in this study, indicate that extracellular vesicles (EVs) in milk and dairy samples contribute to keeping the gut in homeostasis and a low level of inflammation in the gut of newborn infants
The present study shows the opposite tendency, with bEVs being more effective in downregulating the level of IL-6 and IL-1β compared with cEVs (Figure 6)

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Extracellular vesicles (EVs) are secreted from most cells and can be found in body fluids including urine, saliva, blood, and milk. EVs have proven important in facilitating communication between cells by transfer of cargo such as proteins, mRNA, and microRNA (miRNA). The term extracellular vesicles covers both exosomes (20–200 nm) and microvesicles (100–1000 nm). The two types of vesicles differ in biogenesis, but because of overlapping sizes and densities they are difficult to separate [1,2]. EVs are currently receiving a great deal of attention in different fields due to their biological functions as biomarkers, and a huge potential in therapy as an instrument facilitating drug delivery [3,4,5]

Results

Discussion

Conclusion