Milk Small Extracellular Vesicles-derived miRNAs Restrict Porcine Epidemic Diarrhea Virus Infectivity

BackgroundVirus-caused diseases are a huge challenge to both animals and human beings, especially coronaviruses. Porcine epidemic diarrhea virus (PEDV), a coronavirus, causes acute diarrhea and up to 100% mortality in piglets less than three weeks of age. Maternal immunity provides protection for piglets in resisting PEDV infection. Small extracellular vesicles (sEV) contain bioactive molecules such as miRNAs to exchange genetic and epigenetic information between cells. Our previous study suggested that milk sEV facilitated intestinal tract development and prevented LPS-induced intestine damage. However, the effects of milk sEV on the inhibition of viral infections remain unclear. ResultsIn this study, through in vivo experiments, we found that porcine milk sEV protected piglets from PEDV-induced diarrhea and death. In vitro, we clarified that this protective effect was partly generated through the inhibition of the PEDV-N protein and HMGB1 by sEV miR-let-7e and miR-27b, respectively. ConclusionsIn conclusion, we report that porcine milk sEVs protected piglets from PEDV-induced diarrhea and death by inhibiting virus replication, and this protective effect was partly generated through the inhibition of the PEDV-N and HMGB1 pathways by exosomal miR-let-7e and miR-27b. This study reveals a new antiviral function of milk sEVs, and the results suggest that milk sEVs may act as a mother-offspring transmission pathway for protecting newborns against PEDV infection.

Porcine Milk-Derived Small Extracellular Vesicles Promote Intestinal Immunoglobulin Production through pIgR

Secretory immunoglobulin A (SIgA) plays an important role in gut acquired immunity and mucosal homeostasis. Breast milk is the irreplaceable nutritional source for mammals after birth. Current studies have shown the potential functional role of milk-derived small extracellular vesicles (sEVs) and their RNAs cargo in intestinal health and immune regulation. However, there is a lack of studies to demonstrate how milk-derived sEVs affect intestinal immunity in recipient. In this study, through in vivo experiments, we found that porcine milk small extracellular vesicles (PM-sEVs) promoted intestinal SIgA levels, and increased the expression levels of polymeric immunoglobulin receptor (pIgR) both in mice and piglet. We examined the mechanism of how PM-sEVs increased the expression level of pIgR in vitro by using a porcine small intestine epithelial cell line (IPEC-J2). Through bioinformatics analysis, dual-luciferase reporter assays, and overexpression or knockdown of the corresponding non-coding RNAs, we identified circ-XPO4 in PM-sEVs as a crucial circRNA, which leads to the expression of pIgR via the suppression of miR-221-5p in intestinal cells. Importantly, we also observed that oral administration of PM-sEVs increased the level of circ-XPO4 and decreased the level of miR-221-5p in small intestine of piglets, indicating that circRNAs in milk-derived sEVs act as sponge for miRNAs in recipients. This study, for the first time, reveals that PM-sEVs have a capacity to stimulate intestinal SIgA production by delivering circRNAs to receptors and sponging the recipient’s original miRNAs, and also provides valuable data for insight into the role and mechanism of animal milk sEVs in intestinal immunity.

Porcine Colostrum Protects the IPEC-J2 Cells and Piglet Colon Epithelium against Clostridioides (syn. Clostridium) difficile Toxin-Induced Effects

Clostridioides difficile toxins are one of the main causative agents for the clinical symptoms observed during C. difficile infection in piglets. Porcine milk has been shown to strengthen the epithelial barrier function in the piglet’s intestine and may have the potential to neutralise clostridial toxins. We hypothesised that porcine colostrum exerts protective effects against those toxins in the IPEC-J2 cells and in the colon epithelium of healthy piglets. The IPEC-J2 cells were treated with either the toxins or porcine colostrum or their combination. Analyses included measurement of trans-epithelial electrical resistance (TEER), cell viability using propidium iodide by flow cytometry, gene expression of tight junction (TJ) proteins and immune markers, immunofluorescence (IF) histology of the cytoskeleton and a TJ protein assessment. Colon tissue explants from one- and two-week-old suckling piglets and from five-week-old weaned piglets were treated with C. difficile toxins in Ussing chamber assays to assess the permeability to macromolecules (FITC-dextran, HRP), followed by analysis of gene expression of TJ proteins and immune markers. Toxins decreased viability and integrity of IPEC-J2 cells in a time-dependent manner. Porcine colostrum exerted a protective effect against toxins as indicated by TEER and IF in IPEC-J2 cells. Toxins tended to increase paracellular permeability to macromolecules in colon tissues of two-week-old piglets and downregulated gene expression of occludin in colon tissues of five-week-old piglets (p = 0.05). Porcine milk including colostrum, besides other maternal factors, may be one of the important determinants of early immune programming towards protection from C. difficile infections in the offspring.

Draft Genome Sequence of Probiotic Lactobacillus brevis TUCO-5E, Isolated from Porcine Milk

This report describes the draft genome sequence of Lactobacillus brevis TUCO-5E, a probiotic strain isolated from porcine maternal milk. The reads were generated by a whole-genome sequencing (WGS) strategy on an Illumina MiSeq sequencer and were assembled into contigs with a total estimated size of 2,461,089 bp.