The aim of this study was to investigate the therapeutic effect of cow and human milk derived exosomes (MDEs) on colitis. We used gavage administration of fluorescent labeled MDEs to track their localization patterns in vivo and studied their therapeutic effect on colitis in a dextran sulfate sodium (DSS)-induced colitis model. MDEs attenuated the severity of colitis induced by DSS and statistically reduced the histopathological scoring grade and shortening of the colon. Likewise, treatment with MDEs reduced the expression of interleukin 6 and tumor necrosis factor-α. Moreover, miRNAs highly expressed in milk, such as miRNA-320, 375, and Let-7, were found to be more abundant in the colon of MDE-treated mice compared with untreated mice; contrastingly, the expression of their target genes, mainly DNA methyltransferase 1 (DNMT1) and DNMT3 were downregulated. Furthermore, the level of TGF-β was upregulated in the colon of MDE-treated mice. We demonstrated that MDEs have a therapeutic and anti-inflammatory effect on colitis, involving several complementary pathways in its mechanism of action. The therapeutic effects of MDEs might have implications for the possible addition of MDEs as a nutrient in enteral nutrition formulas for patients with inflammatory bowel disease.

Background: Breastfeeding is the ideal source of infant nutrition. Human milk consists not only of nutrients but also biologically active components. Among these latter compounds, exosomes contain proteins, lipids, mRNAs and miRNAs. Methods: To elucidate the biological effects of milk-derived exosomes (MDEs) on normal colonic epithelial cells compared to colonic tumor cells, we incubated cells with MDEs. MDEs were able to enter into normal and tumor cells and change their miRNA expression profiles. Proliferation, cell morphology and protein expression were analyzed in these cells. Results: Human milk-derived exosomes induced proliferation- and epithelial mesenchymal transformation-related changes, such as collagen type I and twist expression, in normal but not in tumor cells. PTEN, a target of miRNA-148a, was downregulated in normal but not in tumor cells following incubation with MDEs. Moreover, miRNA-148a-3p knockdown cells were used to demonstrate the importance of miRNA in the effect of exosomes on cell proliferation and protein expression. MDEs inhibited proliferation and DNMT1 expression in cells with knockdown of miRNA-148a. Conclusions: In conclusion, the positive effect of exosomes on normal cells without affecting tumor cells may presents an aspect of their safety when considering it use as a nutritional supplement to infant formula.

Liver fibrosis is the consequence of various chronic liver diseases, resulting in accumulation of extracellular matrix, following the activation and proliferation of hepatic stellate cells (HSCs). Based on the milk-derived extracellular vesicles’ (MDEs’) characteristics and biological proprieties, we investigate whether MDEs may regulate fibrotic progression by inhibiting HSCs’ activation via the MDEs’ miRNA content. In order to study this question, we examined the effect of human and cow MDEs on HSCs isolated from murine livers, on activation, proliferation and their proteins’ expression. We have shown that MDEs are able to enter into HSCs in vitro and into the livers in vivo. MDEs inhibited HSCs’ proliferation following stimulation with PDGF. Moreover, in vivo treatment with MDEs resulted in an increase of in miRNA-148 and Let7a expression in HSCs. In contrast, treatment with MDEs reduced the expression of miR-21 in HSCs. In addition, MDEs regulate HSC activation, as was shown by downregulation of collagen I expression and alpha smooth muscle actin, and upregulation of PPARγ. MDEs carrying beneficial miRNAs can be a nontoxic natural target for treatment of liver cirrhosis.

Inflammatory bowel disease (IBD) is a chronic, relapsing inflammation disorder of the gastrointestinal tract characterized by disrupted intestinal epithelial barrier function. Despite advances in treatment, including biological agents, achieving sustained remission remains challenging for many patients with IBD. This highlights the urgent need for novel therapeutic strategies. Milk-derived extracellular vesicles (MDEs) have emerged as a promising therapeutic option. In this study, we isolated and characterized MDEs and evaluated their effects on the function of intestinal epithelial cells (IECs). Using a murine model of Dextran Sulfate Sodium (DSS)-induced colitis, we observed that MDEs significantly ameliorated disease symptoms. The upregulation of β-catenin, a crucial mediator of Wnt signaling, in colonic tissues suggests that MDEs may facilitate epithelial regeneration and restore barrier function. In patient-derived colon organoids (PDCOs), MDEs were internalized and modulated the expression of key signaling molecules, such as the upregulation of β-catenin, cyclin D1, and the proliferation marker Ki67, indicating their potential to promote IEC proliferation and intestinal barrier repair. Importantly, MDEs demonstrated selective activity by downregulating β-catenin and cyclin D1 in colon cancer cells, leading to reduced proliferation. This selectivity indicates a dual therapeutic potential of MDEs for promoting healthy IEC proliferation while potentially mitigating malignancy risks.

Recent studies have highlighted the therapeutic potential of small extracellular bodies derived from mesenchymal stem cells (MSC-sEVs) for various diseases, notably through their ability to alter T-cell differentiation and function. The current study aimed to explore immunomodulatory pathway alterations within T cells through mRNA sequencing of activated T cells cocultured with bone marrow-derived MSC-sEVs. mRNA profiling of activated human T cells cocultured with MSC-sEVs or vehicle control was performed using the QIAGEN Illumina sequencing platform. Pathway networks and biological functions of the differentially expressed genes were analyzed using Ingenuity pathway analysis (IPA)^® software, KEGG pathway, GSEA and STRING database. A total of 364 differentially expressed genes were identified in sEV-treated T cells. Canonical pathway analysis highlighted the RhoA signaling pathway. Cellular development, movement, growth and proliferation, cell-to-cell interaction and inflammatory response-related gene expression were altered. KEGG enrichment pathway analysis underscored the apoptosis pathway. GSEA identified enrichment in downregulated genes associated with TNF alpha and interferon gamma response, and upregulated genes related to apoptosis and migration of lymphocytes and T-cell differentiation gene sets. Our findings provide valuable insights into the mechanisms by which MSC-sEVs implement immunomodulatory effects on activated T cells. These findings may contribute to the development of MSC-sEV-based therapies.