Dietary Depletion of Milk Exosomes and Their MicroRNA Cargos Elicits a Depletion of miR-200a-3p and Elevated Intestinal Inflammation and Chemokine (C-X-C Motif) Ligand 9 Expression in Mdr1a Mice

Abstract

Background Exosomes transfer regulatory microRNAs (miRs) from donor cells to recipient cells. Exosomes and miRs originate from both endogenous synthesis and dietary sources such as milk. MicroRNA (miR)-200a-3p is a negative regulator of the pro-inflammatory chemokine (C-X-C motif) ligand 9 (CXCL9). Male Mdr1a−/− mice spontaneously develop clinical signs of inflammatory bowel disease (IBD). Objectives We assessed whether dietary depletion of exosomes and miRs alters the severity of IBD in Mdr1a−/− mice due to aberrant regulation of pro-inflammatory cytokines. Methods Starting at 5 weeks of age, 16 male Mdr1a−/− mice were fed either milk exosome and RNA-sufficient (ERS) or milk exosome and RNA-depleted (ERD) diets. The ERD diet is characterized by a near-complete depletion of miRs and a 60% loss of exosome bioavailability compared to ERS. Mice were euthanized when their weight loss exceeded 15% of peak body weight. Severity of IBD was assessed by histopathological evaluation of cecum. Serum cytokine and chemokine concentrations and mRNA and miR tissue expression were analyzed by multiplex enzyme-linked immunosorbent assays, RNA-sequencing analysis and reverse transcriptase quantitative PCR, respectively. Results Stromal collapse, gland hyperplasia and additive microscopic disease scores were 56.7% ± 23.3%, 23.5% ± 11.8% and 29.6% ± 8.2% lower, respectively, in ceca of ERS mice compared to ERD mice (P < 0.05). The serum concentration of CXCL9 was 35.0% ± 31.0% lower in ERS mice compared to ERD mice (P < 0.05). Eighty-seven mRNAs were differentially expressed in the ceca from ERS and ERD mice; 16 of these mRNAs are implicated in immune function. The levels of four and one out of five miRs assessed (including miR-200a-3p) were up to 63% lower in livers and ceca, respectively, from ERD mice compared to ERS mice. Conclusions Milk exosome and miR depletion exacerbates cecal inflammation in Mdr1a−/− mice.

Biological Properties of Milk-Derived Extracellular Vesicles and Their Physiological Functions in Infant

“…In another study, Mdr1a −/− mice with spontaneous inflammatory bowel disease were divided into two groups: the group fed with milk exosome-and RNA-sufficient (ERS) diet and the group fed with milk exosome-and RNA-depleted (ERD) diets. The study showed that the diet lacking bovine milk-derived exosomes caused miR-200a-3p depletion and elevated intestinal inflammation in Mdr1a −/− mice (Wu et al, 2019). Consistent with this finding, bovine milk-derived exosomes exhibited anti-inflammatory activity in a genetic mouse model of ulcerative colitis, as reported by Stremmel et al (2020).…”

Identification of anti‐inflammatory vesicle‐like nanoparticles in honey

“…miRNAs from ginger‐derived VLNs, including miR‐159a, miR‐166u, and miR‐166p, have been shown to inhibit proliferation of a periodontal pathogen, Porphyromonas gingivalis (Sundaram et al., 2019). Ultrasonication of bovine skim milk leads to a >98% depletion of miRNAs in the milk EVs and a 20% depletion of milk EVs (Leiferman et al., 2018; Wu et al., 2019). When such ultrasonicated skim milk was supplemented in a mouse diet, the expressions of approximately 10 genes in skeletal muscle were altered, compared to mice fed with a diet supplemented with untreated skim milk (Leiferman et al., 2018).…”

“…When such ultrasonicated skim milk was supplemented in a mouse diet, the expressions of approximately 10 genes in skeletal muscle were altered, compared to mice fed with a diet supplemented with untreated skim milk (Leiferman et al., 2018). The same dietary depletion of milk EVs and their miRNA cargos elevated intestinal inflammation and altered transcription of 16 immune genes in Mdr1a –/– mice (Wu et al., 2019). However, it is not clear whether depletion of miRNAs in the milk EVs influences directly transcription in consumers or through other mechanisms (such as reshaping the microbiota in the gut).…”

“…However, such vesicle‐specific markers have not been established in the nanoparticles extracted from vegetables and fruits; therefore, these particles are often termed exosome‐like nanoparticles, or vesicle‐like nanoparticles. Dietary EVs and VLNs have diverse beneficial effects on consumer health (Teng et al., 2018; Wu et al., 2019; Zhang et al., 2016). It has remained unresolved whether honey contains VLNs with any functions.…”

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

“…Milk sEVs-derived RNAs can be absorbed by macrophages and intestinal cells in vitro [ 19 , 20 ], and can enter the circulatory system of milk consumers in vivo [ 21 ]. Recent research has shown that bovine milk exosomal miR-200a-3p is involved in alleviating cecal inflammation in mice [ 22 ].…”