Extracellular vesicles derived miRNAs from bovine milk modulate the inflammatory response to lipopolysaccharide in vitro

Abstract Bovine milk is composed of a variety of biologically active compounds including mi-croRNAs (miRNA), which are found within extracellular vesicles (EVs). Extracellular vesicle-derived miRNAs may play a crucial role in the regulation of the immune response. Thus, this study aimed to identify specific miRNAs present in bovine milk that modulate the immune system’s response to infection. To address this, RAW-Blue™ Cells, a mouse macrophage reporter cell line was challenged with E. coli lipopolysaccharide (LPS) and incubated with a pool of miRNAs isolated from bovine milk through a 24-hour period. After incubation, QUANTI-Blue™ assay was used to detect the activation of the transcription factor NF-κB by the different treatments. Raw-Blue™ cells treated with miRNAs induced to some extend the signaling pathways leading to the activation of NF-κB relative to control cells (P<0.01). Bovine-milk derived miRNAs suppressed LPS-induced NF-κB activity in a dose-dependent manner (P=0.01). To identify the top expressed miRNAs that are driving such effects in vitro, real-time qPCR assays were performed in the milk samples. The miRNA-profiling revealed the presence of miRNAs involved in tumor suppression and cell apoptosis. Overall, our preliminary findings indicated that miRNAs derived from bovine milk have the potential to modulate the immune response to LPS in vitro. Texas Tech University, School of Veterinary Medicine