Uptake and Function Studies of Maternal Milk-derived MicroRNAs

Detection and quantification of miRNA 148a expression in infant formulas

MiRNA 148a, which is associated with various biological processes such as immunity and cell differentiation, is one of the most abundant miRNAs in breast milk. This study aimed to determine the amount of miRNA 148a in different infant formulas, which are used for infants who cannot receive breast milk. The study analyzed 20 formulas, including stage one infant formulas (0-6 months of age), stage two follow-up formulas (6-12 months of age), stage three toddler formulas (above 12 months of age), and premature ones, analyzing miRNA 148a expression and qPCR miRNA gene expression, with significance set at p < 0.05. The expression levels of miRNA 148a in different infant formulas were compared, and no statistically significant difference was observed (p > 0.05). Also, there was no difference in relative miRNA 148a expression across formulas with and without probiotics (p > 0.05). Protein levels in probiotic formulas (0 month-1 year+) were positively correlated with relative miRNA 148a expression (p = 0.022). Although miRNA 148a expression has been shown to be present in formulas, it has been revealed that the amount is low compared to breast milk in line with the literature. In this direction, it is important to increase current data on the mechanisms of action of miRNAs in breast milk and the efforts to ensure that infant formulas reach a composition closest to breast milk in line with their biological effects. PRACTICAL APPLICATION: The miRNAs found in exosomal compounds in human breast milk are very diverse in terms of number and health effects, and can control various biological processes in cells, including immunity, cell differentiation, and apoptosis. One of these is miRNA 148a, which is the most abundant in human breast milk. For this reason, in this study, the miRNA 148a content of infant formulas, which are commonly used in healthy babies who cannot receive enough human breast milk (breastfeeding recommended for at least 6 months and up to 2 years) for a valid reason, was analyzed. In conclusion, miRNA expression has been detected in infant formulas, but it has been shown that this expression is at a low level.

Silence is not always golden: A closer look at potential environmental and ecotoxicological impacts of large-scale dsRNA application

RNA interference (RNAi) technology has emerged as a pivotal strategy in sustainable pest management, offering a targeted approach that significantly mitigates the environmental and health risks associated with traditional insecticides. Originally implemented through genetically modified organisms (GMOs) to produce specific RNAi constructs, the technology has evolved in response to public and regulatory concerns over GMOs. This evolution has spurred the development of non-transgenic RNAi applications such as spray-induced gene silencing (SIGS), which employs double-stranded RNA (dsRNA) to silence pest genes directly without altering the plant's genetic makeup. Despite its advantages in specificity and reduced ecological footprint, SIGS faces significant obstacles, particularly the instability of dsRNA in field conditions, which limits its practical efficacy. To overcome these limitations, innovative delivery mechanisms have been developed. These include nanotechnology-based systems, minicells, and nanovesicles, which are designed to protect dsRNA from degradation and enhance its delivery to target organisms. While these advancements have improved the stability and application efficiency of dsRNA, comprehensive assessments of their environmental safety and the potential for increased exposure risks to non-target organisms remain incomplete. This comprehensive review aims to elucidate the environmental fate of dsRNA and evaluate the potential risks associated with its widespread application on non-target organisms, encompassing soil microorganisms, beneficial insects, host plants, and mammals. The objective is to establish a more refined framework for RNAi risk assessment within environmental and ecotoxicological contexts, thereby fostering the development of safer, non-transgenic RNAi-based pest control strategies.

DsRNA-based pesticides: Considerations for efficiency and risk assessment

In view of the ongoing climate change and the ever-growing world population, novel agricultural solutions are required to ensure sustainable food supply. Microbials, natural substances, semiochemicals and double stranded RNAs (dsRNAs) are all considered potential low risk pesticides. DsRNAs function at the molecular level, targeting specific regions of specific genes of specific organisms, provided that they share a minimal sequence complementarity of approximately 20 nucleotides. Thus, dsRNAs may offer a great alternative to conventional chemicals in environmentally friendly pest control strategies. Any low-risk pesticide needs to be efficient and exhibit low toxicological potential and low environmental persistence. Having said that, in the current review, the mode of dsRNA action is explored and the parameters that need to be taken into consideration for the development of efficient dsRNA-based pesticides are highlighted. Moreover, since dsRNAs mode of action differs from those of synthetic pesticides, custom-made risk assessment schemes may be required and thus, critical issues related to the risk assessment of dsRNA pesticides are discussed here.

Dietary Epigenetic Modulators: Unravelling the Still-Controversial Benefits of miRNAs in Nutrition and Disease

In the context of nutrient-driven epigenetic alterations, food-derived miRNAs can be absorbed into the circulatory system and organs of recipients, especially humans, and potentially contribute to modulating health and diseases. Evidence suggests that food uptake, by carrying exogenous miRNAs (xenomiRNAs), regulates the individual miRNA profile, modifying the redox homeostasis and inflammatory conditions underlying pathological processes, such as type 2 diabetes mellitus, insulin resistance, metabolic syndrome, and cancer. The capacity of diet to control miRNA levels and the comprehension of the unique characteristics of dietary miRNAs in terms of gene expression regulation show important perspectives as a strategy to control disease susceptibility via epigenetic modifications and refine the clinical outcomes. However, the absorption, stability, availability, and epigenetic roles of dietary miRNAs are intriguing and currently the subject of intense debate; additionally, there is restricted knowledge of their physiological and potential side effects. Within this framework, we provided up-to-date and comprehensive knowledge on dietary miRNAs' potential, discussing the latest advances and controversial issues related to the role of miRNAs in human health and disease as modulators of chronic syndromes.

Maternal High Fat Diet in Lactation Impacts Hypothalamic Neurogenesis and Neurotrophic Development, Leading to Later Life Susceptibility to Obesity in Male but Not Female Mice

Early life nutrition can reprogram development and exert long-term consequences on body weight regulation. In mice, maternal high-fat diet (HFD) during lactation predisposed male but not female offspring to diet-induced obesity when adult. Molecular and cellular changes in the hypothalamus at important time points are examined in the early postnatal life in relation to maternal diet and demonstrated sex-differential hypothalamic reprogramming. Maternal HFD in lactation decreased the neurotropic development of neurons formed at the embryo stage (e12.5) and impaired early postnatal neurogenesis in the hypothalamic regions of both males and females. Males show a larger increased ratio of Neuropeptide Y (NPY) to Pro-opiomelanocortin (POMC) neurons in early postnatal neurogenesis, in response to maternal HFD, setting an obese tone for male offspring. These data provide insights into the mechanisms by which hypothalamic reprograming by early life overnutrition contributes to the sex-dependent susceptibility to obesity in adult life in mice.

Human Breast Milk miRNAs: Their Diversity and Potential for Preventive Strategies in Nutritional Therapy

The endogenous miRNAs of breast milk are the products of more than 1000 nonprotein-coding genes, giving rise to mature small regulatory molecules of 19-25 nucleotides. They are incorporated in macromolecular complexes, loaded on Argonaute proteins, sequestrated in exosomes and lipid complexes, or present in exfoliated cells of epithelial, endothelial, or immune origins. Their expression is dependent on the stage of lactation; however, their detection depends on progress in RNA sequencing and the reappraisal of the definition of small RNAs. Some miRNAs from plants are detected in breast milk, opening the possibility of the stimulation of immune cells from the allergy repertoire. Each miRNA harbors a seeding sequence, which targets mRNAs, gene promoters, or long noncoding RNAs. Their activities depend on their bioavailability. Efficient doses of miRNAs are estimated to be roughly 100 molecules in the cytoplasm of target cells from in vitro and in vivo experiments. Each miRNA is included in networks of stimulation/inhibition/sequestration, driving the expression of cellular phenotypes. Three types of stress applied during lactation to manipulate miRNA supply were explored using rodent offspring: a foster mother, a cafeteria diet, and early weaning. This review presents the main mature miRNAs described from current mothers' cohorts and their bioavailability in experimental models as well as studies assessing the potential of miR-26 or miR-320 miRNA families to alter offspring phenotypes.

The Role of microRNAs in Arsenic-Induced Human Diseases: A Review

MicroRNAs (miRNAs) are noncoding RNAs with 20-22 nucleotides, which are encoded by endogenous genes and are capable of targeting the majority of human mRNAs. Arsenic is regarded as a human carcinogen, which can lead to many adverse health effects including diabetes, skin lesions, kidney disease, neurological impairment, male reproductive injury, and cardiovascular disease (CVD) such as cardiac arrhythmias, ischemic heart failure, and endothelial dysfunction. miRNAs can act as tumor suppressors and oncogenes via directly targeting oncogenes or tumor suppressors. Recently, miRNA dysregulation was considered to be an important mechanism of arsenic-induced human diseases and a potential biomarker to predict the diseases caused by arsenic exposure. Endogenic miRNAs such as miR-21, the miR-200 family, miR-155, and the let-7 family are involved in arsenic-induced human disease by inducing translational repression or RNA degradation and influencing multiple pathways, including mTOR/Arg 1, HIF-1α/VEGF, AKT, c-Myc, MAPK, Wnt, and PI3K pathways. Additionally, exogenous miRNAs derived from plants, such as miR-34a, miR-159, miR-2911, miR-159a, miR-156c, miR-168, etc., among others, can be transported from blood to specific tissue/organ systems in vivo. These exogenous miRNAs might be critical players in the treatment of human diseases by regulating host gene expression. This review summarizes the regulatory mechanisms of miRNAs in arsenic-induced human diseases, including cancers, CVD, and other human diseases. These special miRNAs could serve as potential biomarkers in the management and treatment of human diseases linked to arsenic exposure. Finally, the protective action of exogenous miRNAs, including antitumor, anti-inflammatory, anti-CVD, antioxidant stress, and antivirus are described.

Plant miRNA bol-miR159 Regulates Gut Microbiota Composition in Mice: In Vivo Evidence of the Crosstalk between Plant miRNAs and Intestinal Microbes

New evidence reveals that bol-miR159, an miRNA rich in fruits and vegetables, cross-kingdomly functions in mammalian bodies. However, whether the miRNA could regulate gut microbiota remains unclear. Here, the effect of miR159 on mouse intestinal microbes was comprehensively examined. The results showed that supplementation of miR159 to the chow diet significantly enhanced the diversity of mouse gut microbiota without causing pathological lesions or inflammatory responses on the intestines. At the phylum level, miR159 increased the abundance of Proteobacteria and decreased the Firmicute-to-Bacteroidetes (F/B) ratio. miR159 had prebiotic-like effects on mouse gut microbiota, as it promoted the growth of the bacteria that is beneficial for maintaining gut health. The miRNA can target bacteria genes and get into the bacteria cells. The data provide direct in vivo evidence on the crosstalk between plant miRNAs and intestinal microbes, highlighting the potential for miRNA-based strategies that modulate gut microbes to improve host health.

A comprehensive review on infant formula: nutritional and functional constituents, recent trends in processing and its impact on infants' gut microbiota

Human milk is considered the most valuable form of nutrition for infants for their growth, development and function. So far, there are still some cases where feeding human milk is not feasible. As a result, the market for infant formula is widely increasing, and formula feeding become an alternative or substitute for breastfeeding. The nutritional value of the formula can be improved by adding functional bioactive compounds like probiotics, prebiotics, human milk oligosaccharides, vitamins, minerals, taurine, inositol, osteopontin, lactoferrin, gangliosides, carnitine etc. For processing of infant formula, diverse thermal and non-thermal technologies have been employed. Infant formula can be either in powdered form, which requires reconstitution with water or in ready-to-feed liquid form, among which powder form is readily available, shelf-stable and vastly marketed. Infants' gut microbiota is a complex ecosystem and the nutrient composition of infant formula is recognized to have a lasting effect on it. Likewise, the gut microbiota establishment closely parallels with host immune development and growth. Therefore, it must be contemplated as an important factor for consideration while developing formulas. In this review, we have focused on the formulation and manufacturing of safe and nutritious infant formula equivalent to human milk or aligning with the infant's needs and its ultimate impact on infants' gut microbiota.

The use of plant-derived exosome-like nanoparticles as a delivery system of CRISPR/Cas9-based therapeutics for editing long non-coding RNAs in cancer colon cells

Colon cancer is one of the leading causes of cancer in the United States. Colon cancer develops from the many gene mutations found in the genomes of colon cancer cells. Long non-coding RNAs (lncRNAs) can cause the development and progression of many cancers, including colon cancer. LncRNAs have been and could be corrected through the gene-editing technology of the clustered repeats of the clustered regularly interspaced short palindromic repeats (CRISPR)-associated nuclease 9 (CRISPR/Cas9) system to reduce the proliferation of cancer cells in the colon. However, many current delivery systems for transporting CRISPR/Cas9-based therapeutics in vivo need more safety and efficiency. CRISPR/Cas9-based therapeutics require a safe and effective delivery system to more directly and specifically target cancer cells present in the colon. This review will present pertinent evidence for the increased efficiency and safety of using plant-derived exosome-like nanoparticles as nanocarriers for delivering CRISPR/Cas9-based therapeutics to target colon cancer cells directly.

Uncovering the gastrointestinal passage, intestinal epithelial cellular uptake and AGO2 loading of milk miRNAs in neonates using xenomiRs as tracers

BACKGROUND

Human breast milk has a high microRNA (miRNA) content. It remains unknown whether and how milk miRNAs might affect intestinal gene regulation and homeostasis of the developing microbiome after initiation of enteral nutrition. However, this requires that relevant milk miRNA amounts survive gastrointestinal passage, are taken up by cells, and become available to the RNA interference (RNAi) machinery. It seems important to dissect the fate of these miRNAs after oral ingestion and gastrointestinal passage.

OBJECTIVE

Our goal was to analyze the potential transmissibility of milk miRNAs via the gastrointestinal system in neonate humans and a porcine model in vivo to contribute to the discussion whether milk miRNAs could influence gene regulation in neonates and thus might vertically transmit developmental relevant signals.

DESIGN

We performed cross-species profiling of miRNAs via deep-sequencing and utilized dietary xenobiotic taxon-specific milk miRNA (xenomiRs) as tracers in human and porcine neonates, followed by functional studies in primary human fetal intestinal epithelial cells (HIEC-6) using Ad5-mediated miRNA-gene transfer.

RESULTS

Mammals share many milk miRNAs yet exhibit taxon-specific miRNA fingerprints. We traced bovine-specific miRNAs from formula-nutrition in human preterm stool and 9 days after onset of enteral feeding in intestinal cells of preterm piglets. Thereafter, several xenomiRs accumulated in the intestinal cells. Moreover, few hours after introducing enteral feeding in preterm piglets with supplemented reporter miRNAs (cel-miR-39-5p/-3p), we observed their enrichment in blood serum and in AGO2-immunocomplexes from intestinal biopsies.

CONCLUSIONS

Milk-derived miRNAs survived gastrointestinal passage in human and porcine neonates. Bovine-specific miRNAs accumulated in intestinal cells of preterm piglets after enteral feeding with bovine colostrum/formula. In piglets, colostrum supplementation with cel-miR-39-5p/-3p resulted in increased blood levels of cel-miR-39-3p and argonaute RISC catalytic component 2 (AGO2) loading in intestinal cells. This suggests the possibility of vertical transmission of miRNA signaling from milk through the neonatal digestive tract.

Changes in microRNAs during Storage and Processing of Breast Milk

Human breast milk (HBM) is the ideal source of nutrients for infants and is rich in microRNA (miRNA). In recent years, expressed breast milk feeding rather than direct breastfeeding has become increasingly prevalent for various reasons. Expressed HBM requires storage and processing, which can cause various changes in the ingredients. We investigated how the miRNAs in HBM change due to processes often used in real life. HBM samples collected from 10 participants were each divided into seven groups according to the storage temperature, thawing method, and storage period. In addition, we analyzed the miRNA changes in each group. The number of microRNAs that showed significant expression was not large compared to the thousands of miRNAs contained in breast milk. Therefore, it is difficult to suggest that the various storage and thawing processes have a great influence on the overall expression of miRNA. However, a short-term refrigeration storage method revealed little change in nutrients compared to other storage and thawing methods. Taking all factors into consideration, short-term refrigeration is recommended to minimize changes in the composition or function of breast milk.

Suppression of milk-derived miR-148a caused by stress plays a role in the decrease in intestinal ZO-1 expression in infants

BACKGROUND & AIMS

Milk-derived miR-148a-3p (miR-148a), which is abundant in breast milk, has been shown to be associated with the development of infants' intestines. Although it is well known that stress during lactation changes milk constituents in terms of lipid and protein, no studies have examined the influence of stress on miR-148a expression in breast milk. The objective of this study is to investigate the relationship between stress and miR-148a expression in milk, and to evaluate whether the changes in milk-derived miR-148a expression-caused by the mother's exposure to stress-influence intestinal ZO-1 expression in infants.

METHODS

The participants of this study were healthy Japanese women who were nursing. Psychological stress evaluation of the subjects was conducted using a short form of the Profile of Mood State Second Edition-Adult (POMS-2). Additionally, miR-148a expressions in restraint stressed nursing mice were investigated using quantitative real-time PCR. The levels of a tight junction protein zonula occludens-1 (ZO-1) and DNA methyltransferase 1 (DNMT1), which is a direct target of miR-148a, in ileum in neonatal mice breastfed by stressed nursing mice were investigated using Western blot. Furthermore, to investigate the influence of miR-148a on ZO-1 expression within the intestine, the levels of ZO-1 and DNMT1 in human intestinal epithelial Caco-2 cells with lentivirus-mediated miR-148a overexpression were evaluated.

RESULTS

A significantly negative correlation was observed between relative miR-148a expression in breast milk and the total mood disturbance T-score. Each T-score on negative mood subscales of anger-hostility, confusion-bewilderment, depression-dejection, fatigue-inertia, and tension-anxiety was significantly negatively correlated with relative miR-148a expression in breast milk: a positive mood subscale vigor-activity T-score was significantly positively correlated with relative miR-148a expression in breast milk. A positive mood friendliness T-score, estimated separately from other scores, was significantly positively correlated with relative miR-148a expression in breast milk. Additionally, the relative expression of miR-148a in the milk obtained from stressed mice was significantly lower than that of control mice. The relative level of ZO-1 in ileum of neonatal mice nursed by stressed mice was significantly lower than that of neonatal mice nursed by control mice. Additionally, the relative level of DNMT1 in ileum of neonatal mice nursed by stressed mice was significantly higher than that of neonatal mice nursed by control mice. Furthermore, the relative level of ZO-1 in miR-148a-overexpressed Caco-2 cells was significantly higher than that in control cells. The relative level of DNMT1 in miR-148a-overexpressed Caco-2 cells was significantly lower than that in control cells.

CONCLUSIONS

Mothers' exposure to stress during lactation may cause miR-148a expression in breast milk. Additionally, stressed-induced suppression of miR-148a expression in breast milk may cause a decrease in intestinal ZO-1 level via the increase in DNMT1 in infants' intestines. These observations are beneficial information for breastfeeding mothers and their families and perinatal medical professionals. Our findings encourage monitoring maternal psychological stress during lactation to promote breastfeeding and adequate infant nutrition.

Exogenous miRNAs from Moringa oleifera Lam. recover a dysregulated lipid metabolism

A balanced diet is critical for human health, and edible plants play an important role in providing essential micronutrients as well as specific microRNAs (miRNAs) that can regulate human gene expression. Here we present the effects of Moringa oleifera (MO) miRNAs (mol-miRs) on lipid metabolism. Through in silico studies we identified the potential genes involved in lipid metabolism targeted by mol-miRs. To this end, we tested the efficacy of an aqueous extract of MO seeds (MOES), as suggested in traditional African ethnomedicine, or its purified miRNAs. The biological properties of MO preparations were investigated using a human derived hepatoma cell line (HepG2) as a model. MOES treatment decreased intracellular lipid accumulation and induced apoptosis in HepG2. In the same cell line, transfection with mol-miRs showed similar effects to MOES. Moreover, the effect of the mol-miR pool was investigated in a pre-obese mouse model, in which treatment with mol-miRs was able to prevent dysregulation of lipid metabolism.

Exosome Carrier Effects; Resistance to Digestion in Phagolysosomes May Assist Transfers to Targeted Cells; II Transfers of miRNAs Are Better Analyzed via Systems Approach as They Do Not Fit Conventional Reductionist Stoichiometric Concepts

Carrier effects of extracellular vesicles (EV) like exosomes refer to properties of the vesicles that contribute to the transferred biologic effects of their contents to targeted cells. This can pertain to ingested small amounts of xenogeneic plant miRNAs and oral administration of immunosuppressive exosomes. The exosomes contribute carrier effects on transfers of miRNAs by contributing both to the delivery and the subsequent functional intracellular outcomes. This is in contrast to current quantitative canonical rules that dictate just the minimum copies of a miRNA for functional effects, and thus successful transfers, independent of the EV carrier effects. Thus, we argue here that transfers by non-canonical minute quantities of miRNAs must consider the EV carrier effects of functional low levels of exosome transferred miRNA that may not fit conventional reductionist stoichiometric concepts. Accordingly, we have examined traditional stoichiometry vs. systems biology that may be more appropriate for delivered exosome functional responses. Exosome carrier properties discussed include; their required surface activating interactions with targeted cells, potential alternate targets beyond mRNAs, like reaching a threshold, three dimensional aspects of the RNAs, added EV kinetic dynamic aspects making transfers four dimensional, and unique intracellular release from EV that resist intracellular digestion in phagolysosomes. Together these EV carrier considerations might allow systems analysis. This can then result in a more appropriate understanding of transferred exosome carrier-assisted functional transfers. A plea is made that the miRNA expert community, in collaboration with exosome experts, perform new experiments on molecular and quantitative miRNA functional effects in systems that include EVs, like variation in EV type and surface constituents, delivery, dose and time to hopefully create more appropriate and truly current canonical concepts of the consequent miRNA functional transfers by EVs like exosomes.

Milk exosomes in nutrition and drug delivery

Exosomes are natural nanoparticles that originate in the endocytic system. Exosomes play an important role in cell-to-cell communication by transferring RNAs, lipids, and proteins from donor cells to recipient cells or by binding to receptors on the recipient cell surface. The concentration of exosomes and the diversity of cargos are high in milk. Exosomes and their cargos resist degradation in the gastrointestinal tract and during processing of milk in dairy plants. They are absorbed and accumulate in tissues following oral administrations, cross the blood-brain barrier, and dietary depletion and supplementation elicit phenotypes. These features have sparked the interest of the nutrition and pharmacology communities for exploring milk exosomes as novel bioactive food compounds and for delivering drugs to diseased tissues. This review discusses the current knowledgebase, uncertainties, and controversies in these lines of scholarly endeavor and health research.

Recent trends in miRNA therapeutics and the application of plant miRNA for prevention and treatment of human diseases

Background

Researchers now have a new avenue to investigate when it comes to miRNA-based therapeutics. miRNAs have the potential to be valuable biomarkers for disease detection. Variations in miRNA levels may be able to predict changes in normal physiological processes. At the epigenetic level, miRNA has been identified as a promising candidate for distinguishing and treating various diseases and defects.

Main body

In recent pharmacology, plants miRNA-based drugs have demonstrated a potential role in drug therapeutics. The purpose of this review paper is to discuss miRNA-based therapeutics, the role of miRNA in pharmacoepigenetics modulations, plant miRNA inter-kingdom regulation, and the therapeutic value and application of plant miRNA for cross-kingdom approaches. Target prediction and complementarity with host genes, as well as cross-kingdom gene interactions with plant miRNAs, are also revealed by bioinformatics research. We also show how plant miRNA can be transmitted from one species to another by crossing kingdom boundaries in this review. Despite several unidentified barriers to plant miRNA cross-transfer, plant miRNA-based gene regulation in trans-kingdom gene regulation may soon be valued as a possible approach in plant-based drug therapeutics.

Conclusion

This review summarised the biochemical synthesis of miRNAs, pharmacoepigenetics, drug therapeutics and miRNA transkingdom transfer.

A bovine miRNA, bta-miR-154c, withstands in vitro human digestion but does not affect cell viability of colorectal human cell lines after transfection

Colorectal cancer (CRC) is the third most frequent human cancer with over 1.3 million new cases globally. CRC is a complex disease caused by interactions between genetic and environmental factors; in particular, high consumption of red meat, including beef, is considered a risk factor for CRC initiation and progression. Recent data demonstrate that exogenous microRNAs (miRNAs) entering the body via ingestion could pose an effect on the consumer. In this study, we focused on bovine miRNAs that do not share a seed sequence with humans and mice. We identified bta-miR-154c, a bovine miRNA found in edible parts of beef and predicted via cross-species bioinformatic analysis to affect cancer-related pathways in human cells. When bovine tissue was subjected to cooking and a simulation of human digestion, bta-miR-154c was still detected after all procedures, albeit at reduced concentrations. However, lipofection of bta-miR-154c in three different colorectal human cell lines did not affect their viability as evaluated at various time points and concentrations. These data indicate that bta-miR-154c (a) may affect cancer-related pathways in human cells, (b) can withstand digestion and be detected after all stages of an in vitro digestion protocol, but (c) it does not appear to alter epithelial cell viability after entering human enterocytes, even at supraphysiological amounts. Further experiments will elucidate whether bta-miR-154c exerts a different functional effect on the human gut epithelium, which may cause it to contribute to CRC progression through its consumption.

Identification of Bovine miRNAs with the Potential to Affect Human Gene Expression

Milk and other products from large mammals have emerged during human evolution as an important source of nutrition. Recently, it has been recognized that exogenous miRNAs (mRNA inhibited RNA) contained in milk and other tissues of the mammalian body can enter the human body, which in turn have the ability to potentially regulate human metabolism by affecting gene expression. We studied for exogenous miRNAs from Bos taurus that are potentially contain miRNAs from milk and that could act postprandially as regulators of human gene expression. The interaction of 17,508 human genes with 1025 bta-miRNAs, including 245 raw milk miRNAs was studied. The milk bta-miR-151-5p, bta-miR-151-3p, bta-miRNA-320 each have 11 BSs (binding sites), and bta-miRNA-345-5p, bta-miRNA-614, bta-miRNA-1296b and bta-miRNA-149 has 12, 14, 15 and 26 BSs, respectively. The bta-miR-574-5p from cow’s milk had 209 human genes in mRNAs from one to 25 repeating BSs. We found 15 bta-miRNAs that have 100% complementarity to the mRNA of 13 human target genes. Another 12 miRNAs have BSs in the mRNA of 19 human genes with 98% complementarity. The bta-miR-11975, bta-miR-11976, and bta-miR-2885 BSs are located with the overlap of nucleotide sequences in the mRNA of human genes. Nucleotide sequences of BSs of these miRNAs in 5′UTR mRNA of human genes consisted of GCC repeats with a total length of 18 nucleotides (nt) in 18 genes, 21 nt in 11 genes, 24 nt in 14 genes, and 27–48 nt in nine genes. Nucleotide sequences of BSs of bta-miR-11975, bta-miR-11976, and bta-miR-2885 in CDS mRNA of human genes consisted of GCC repeats with a total length of 18 nt in 33 genes, 21 nt in 13 genes, 24 nt in nine genes, and 27–36 nt in 11 genes. These BSs encoded polyA or polyP peptides. In only one case, the polyR (SLC24A3 gene) was encoded. The possibility of regulating the expression of human genes by exogenous bovine miRNAs is discussed.

Longitudinal Human Milk miRNA Composition over the First 3 mo of Lactation in a Cohort of Healthy Mothers Delivering Term Infants

BACKGROUND

MicroRNAs (miRNAs) are small noncoding RNAs involved in posttranscriptional regulation. miRNAs can be secreted and found in many body fluids, and although they are particularly abundant in breastmilk, their functions remain elusive. Human milk (HM) miRNAs start to raise considerable interest, but a comprehensive understanding of the repertoire and expression profiles along lactation has not been well characterized.

OBJECTIVES

This study aimed to characterize the longitudinal profile of HM miRNA between the second week and third month postpartum.

METHODS

We used a new sensitive technology to measure HM miRNAs in a cohort of 44 French mothers [mean ± SD age: 31 ± 3.5; BMI (in kg/m2) 21.8 ± 2.3] who delivered at term and provided HM samples at 3 time points (17 ± 3 d, 60 ± 3 d, and 90 ± 3 d) during follow-up visits.

RESULTS

We detected 685 miRNAs, of which 35 showed a high and stable expression along the lactation period analyzed. We also described for the first time a set of 11 miRNAs with a dynamic expression profile. To gain insight into the potential functional relevance of this set of miRNAs, we selected miR-3126 and miR-3184 to treat undifferentiated Caco-2 human intestinal cells and then assessed differentially expressed genes and modulation of related biological pathways.

CONCLUSIONS

Overall, our study provides new insights into HM miRNA composition and, to our knowledge, the first description of its longitudinal dynamics in mothers who delivered at term. Our in vitro results obtained in undifferentiated Caco-2 human intestinal cells transfected with HM miRNAs also provide further support to the hypothesized mother-to-neonate signaling role of HM miRNAs. This trial was registered at clinicaltrials.gov as NCT01894893.

RNAi for Western Corn Rootworm Management: Lessons Learned, Challenges, and Future Directions

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is considered one of the most economically important pests of maize (Zea mays L.) in the United States (U.S.) Corn Belt with costs of management and yield losses exceeding USD ~1-2 billion annually. WCR management has proven challenging given the ability of this insect to evolve resistance to multiple management strategies including synthetic insecticides, cultural practices, and plant-incorporated protectants, generating a constant need to develop new management tools. One of the most recent developments is maize expressing double-stranded hairpin RNA structures targeting housekeeping genes, which triggers an RNA interference (RNAi) response and eventually leads to insect death. Following the first description of in planta RNAi in 2007, traits targeting multiple genes have been explored. In June 2017, the U.S. Environmental Protection Agency approved the first in planta RNAi product against insects for commercial use. This product expresses a dsRNA targeting the WCR snf7 gene in combination with Bt proteins (Cry3Bb1 and Cry34Ab1/Cry35Ab1) to improve trait durability and will be introduced for commercial use in 2022.

Identification and bioinformatics analysis of differentially expressed milk exosomal microRNAs in milk exosomes of heat-stressed Holstein cows

In summer, heat stress is one of the primary reasons for the compromised health and low milk productivity of dairy cows. Hyperthermia affects milk synthesis and secretion in the mammary glands of dairy cows. As molecules for intercellular communication, milk-derived exosomes carry genetic material, proteins, and lipids, playing a crucial role in mammary tissue growth and milk synthesis in dairy cows. The aim of this study was to explore the milk exosomal miRNA profile of heat-stressed and normal Holstein cows. We isolated and identified milk exosomes to screening for differentially expressed miRNAs using small RNA sequencing. Then, TargetScan and miRanda algorithms were used to predict the putative targets of the differentially expressed miRNAs, whereas GO and KEGG pathway enrichment analyses were performed for the differentially expressed miRNA-target genes. Our results showed that 215 miRNAs were significantly differentially expressed in heat-stressed milk exosomes, of which one was upregulated and 214 were significantly downregulated. GO and KEGG enrichment analyses indicated that differentially expressed miRNAs might play a role in apoptosis, autophagy, and the p38 MAPK pathway. qRT-PCR assay verified that the expression of miRNAs was consistent with the sequencing results, warranting further verification of their specific targets of action. In conclusion, changes in the miRNA expression profile of milk exosomes indicated the role of exosomal miRNAs in regulating heat stress resistance and apoptosis in dairy cows. Our results suggested that milk-derived exosomal miRNAs could increase mammary gland resistance to heat stress, thereby enhancing milk synthesis in dairy cows.

Up-to-date on the evidence linking miRNA-related epitranscriptomic modifications and disease settings. Can these modifications affect cross-kingdom regulation?

The field of epitranscriptomics is rapidly developing. Several modifications (e.g. methylations) have been identified for different RNA types. Current evidence shows that chemical RNA modifications can influence the whole molecule's secondary structure, translatability, functionality, stability, and degradation, and some are dynamically and reversibly modulated. miRNAs, in particular, are not only post-transcriptional modulators of gene expression but are themselves submitted to regulatory mechanisms. Understanding how these modifications are regulated and the resulting pathological consequences when dysregulation occurs is essential for the development of new therapeutic targets. In humans and other mammals, dietary components have been shown to affect miRNA expression and may also induce chemical modifications in miRNAs. The identification of chemical modifications in miRNAs (endogenous and exogenous) that can impact host gene expression opens up an alternative way to select new specific therapeutic targets.Hence, the aim of this review is to briefly address how RNA epitranscriptomic modifications can affect miRNA biogenesis and to summarize the existing evidence showing the connection between the (de)regulation of these processes and disease settings. In addition, we hypothesize on the potential effect certain chemical modifications could have on the potential cross-kingdom journey of dietary plant miRNAs.

Exosomes provide unappreciated carrier effects that assist transfers of their miRNAs to targeted cells; I. They are 'The Elephant in the Room'

Extracellular vesicles (EV), such as exosomes, are emerging biologic entities that mediate important newly recognized functional effects. Exosomes are intracellular endosome-originating, cell-secreted, small nano-size EV. They can transfer cargo molecules like miRNAs to act intracellularly in targeted acceptor cells, to then mediate epigenetic functional alterations. Exosomes among EV, are universal nanoparticles of life that are present across all species. Some critics mistakenly hold exosomes to concepts and standards of cells, whereas they are subcellular nanospheres that are a million times smaller, have neither nuclei nor mitochondria, are far less complex and currently cannot be studied deeply and elegantly by many and diverse technologies developed for cells over many years. There are important concerns about the seeming impossibility of biologically significant exosome transfers of very small amounts of miRNAs resulting in altered targeted cell functions. These hesitations are based on current canonical concepts developed for non-physiological application of miRNAs alone, or artificial non-quantitative genetic expression. Not considered is that the natural physiologic intercellular transit via exosomes can contribute numerous augmenting carrier effects to functional miRNA transfers. Some of these are particularly stimulated complex extracellular and intracellular physiologic processes activated in the exosome acceptor cells that can crucially influence the intracellular effects of the transferred miRNAs. These can lead to molecular chemical changes altering DNA expression for mediating functional changes of the targeted cells. Such exosome mediated molecular transfers of epigenetic functional alterations, are the most exciting and life-altering property that these nano EV bring to virtually all of biology and medicine. .Abbreviations: Ab, Antibody Ag Antigen; APC, Antigen presenting cells; CS, contact sensitivity; DC, Dendritic cells; DTH, Delayed-type hypersensitivity; EV, extracellular vesicles; EV, Extracellular vesicle; FLC, Free light chains of antibodies; GI, gastrointestinal; IP, Intraperitoneal administration; IV, intravenous administration; OMV, Outer membrane vesicles released by bacteria; PE, Phos-phatidylethanolamine; PO, oral administration.

Dietary bovine milk miRNAs transported in extracellular vesicles are partially stable during GI digestion, are bioavailable and reach target tissues but need a minimum dose to impact on gene expression

PURPOSE

Extracellular RNAs are unstable and rapidly degraded unless protected. Bovine-milk extracellular vesicles (EVs) confer protection to dietary miRNAs, although it remains unclear whether this importantly improves their chances of reaching host target cells to exert biological effects.

METHODS

Caco-2, HT-29, Hep-G2 and FHs-74 cell lines were exposed to natural/labelled milk EVs to evaluate cellular uptake. Five frequently reported human milk miRNAs (miR-146b-5p, miR-148a-3p, miR-30a-5p, miR-26a-5p, and miR-22-3p) were loaded into EVs. The intracellular concentration of each miRNA in cells was determined. In addition, an animal study giving an oral dose of loaded EVs in C57BL6/ mice were performed. Gene expression regulation was assessed by microarray analysis.

RESULTS

Digestive stability analysis showed high overall degradation of exogenous miRNAs, although EV-protected miRNAs better resisted gastrointestinal digestion compared to free miRNAs (tenfold higher levels). Importantly, orally delivered EV-loaded miRNAs reached host organs, including brain, in mice. However, no biological effect has been identified.

CONCLUSION

Milk EVs protect miRNAs from degradation and facilitate cellular uptake. miRNA concentration in EVs from bovine milk might be insufficient to produce gene modulation. Nevertheless, sizable amounts of exogenous miRNAs may be loaded into EVs, and orally delivered EV-loaded miRNAs can reach tissues in vivo, increasing the possibility of exerting biological effects. Further investigation is justified as this could have an impact in the field of nutrition and health (i.e., infant formulas elaboration).

Exosome-based therapies for mucosal delivery

Exosomes are membrane-bound extracellular nanovesicles secreted by most cells and found in multiple sources, including bodily fluids, plants, fruit, and bovine milk. They play an important role as mediators of intercellular communication, having a distinct ability to carry small molecules, proteins, and nucleic acids to recipient cells over large distances. Moreover, competency in crossing usually poorly permeable biological barriers has led to their promising use in diagnostics and in therapeutics, either as therapeutic entities on their own or as drug delivery vehicles, with superior stability, biocompatibility, circulation time and target specificity in comparison to conventional drug delivery systems. The aim of this review is to summarise and critically discuss the current literature on the use of exosomes in a therapeutic setting, with a particular focus on their use as drug delivery vehicles for mucosal drug delivery.

Cross-kingdom regulation by dietary plant miRNAs: an evidence-based review with recent updates

As non-coding RNA molecules, microRNAs (miRNAs) are widely known for their critical role in gene regulation. Recent studies have shown that plant miRNAs obtained through dietary oral administration can survive in the gastrointestinal (GI) tract, enter the circulatory system and regulate endogenous mRNAs. Diet-derived plant miRNAs have 2'-O-methylated modified 3'ends and high cytosine and guanine (GC) content, as well as exosomal packaging, which gives them high stability even in the harsh environment of the digestive system and circulatory system. The latest evidence shows that dietary plant miRNAs can not only be absorbed in the intestine, but also be absorbed and packaged by gastric epithelial cells and then secreted into the circulatory system. Alternatively, these biologically active plant-derived miRNAs may also affect the health of the host by affecting the function of the microbiome, while not need to be taken into the host's circulatory system and transferred to remote tissues. This cross-kingdom regulation of miRNAs gives us hope for exploring their therapeutic potential and as dietary supplements. However, doubts have also been raised about the cross-border regulation of miRNAs, suggesting that technical flaws in the experiments may have led to this hypothesis. In this article, we summarize the visibility of dietary plant miRNAs in the development of human health and recent research data on their use in therapeutics. The regulation of plant miRNAs across kingdoms is a novel concept. Continued efforts in this area will broaden our understanding of the biological role of plant miRNAs and will open the way for the development of new approaches to prevent or treat human diseases.

Comparison of methods for pre-processing, exosome isolation, and RNA extraction in unpasteurized bovine and human milk

Milk is a highly complex, heterogeneous biological fluid that contains non-nutritive, bioactive extracellular vesicles called exosomes. Characterization of milk-derived exosomes (MDEs) is challenging due to the lack of standardized methods that are currently being used for milk pre-processing, storage, and exosome isolation. In this study, we tested: 1) three pre-processing methods to remove cream, fat, cellular debris, and casein proteins from bovine milk to determine whether pre-processing of whole milk prior to long-term storage improves MDE isolations, 2) the suitability of two standard exosome isolation methods for MDE fractionation, and 3) four extraction protocols for obtaining high quality RNA from bovine and human MDEs. MDEs were characterized via Transmission Electron Microscopy (TEM), Nanoparticle Tracking Analysis (NTA), and western immunoblotting for CD9, CD63, and Calnexin protein markers. We also present an optimized method of TEM sample preparation for MDEs. Our results indicate that: 1) Removal of cream and fat globules from unpasteurized bovine milk, prior to long-term storage, improves the MDE yield but not purity, 2) Differential ultracentrifugation (DUC) combined with serial filtration is better suited for bovine MDE isolation compared to ExoQuick (EQ) combined with serial filtration, however both methods were comparable for human milk, and 3) TRIzol LS is better suited for RNA extraction from bovine MDEs isolated by EQ and DUC methods. 4) TRIzol LS, TRIzol+RNA Clean and Concentrator, and TRIzol LS+RNA Clean and Concentrator methods can be used for RNA extractions from human MDEs isolated by EQ, yet the TRIzol LS method is better suited for human MDEs isolated by DUC. The QIAzol + miRNeasy Mini Kit produced the lowest RNA yield for bovine and human MDEs.

Breed differences in the expression levels of gga-miR-222a in laying hens influenced H2S production by regulating methionine synthase genes in gut bacteria

BACKGROUND

The microbiota in the cecum of laying hens is crucial for host digestion, metabolism, and odor gas production. The results of recent studies have suggested that host microRNAs (miRNAs) can regulate gene expression of the gut microbiota. In the present study, the expression profiles of host-derived miRNAs in the cecal content of two laying hen breeds; Hy-line Gray and Lohmann Pink, which have dissimilar H₂S production, were characterized; and their effects on H₂S production by regulating the expression of gut microbiota-associated genes were demonstrated.

RESULTS

The differential expression of microbial serine O-acetyltransferase, methionine synthase, aspartate aminotransferase, methionine-gamma-lyase, and adenylylsulfate kinase between the two hen breeds resulted in lower H₂S production in the Hy-line hens. The results also revealed the presence of miRNA exosomes in the cecal content of laying hens, and an analysis of potential miRNA-target relationships between 9 differentially expressed miRNAs and 9 differentially expressed microbial genes related to H₂S production identified two methionine synthase genes, Odosp_3416 and BF9343_2953, that are targeted by gga-miR-222a. Interestingly, in vitro fermentation results showed that gga-miR-222a upregulates the expression of these genes, which increased methionine concentrations but decreased H₂S production and soluble sulfide concentrations, indicating the potential of host-derived gga-miR-222a to reduce H₂S emission in laying hens.

CONCLUSION

The findings of the present study reveal both a physiological role by which miRNAs shape the cecal microbiota of laying hens and a strategy to use host miRNAs to manipulate the microbiome and actively express key microbial genes to reduce H₂S emissions and breed environmentally friendly laying hens. Video Abstract.

Plant-derived exosome-like nanoparticles and their therapeutic activities

Nanotechnologies have been successfully applied to the treatment of various diseases. Plant-derived exosome-like nanoparticles (PENs) are expected to become effective therapeutic modalities for treating disease or in drug-delivery. PENs are minimally cytotoxic to healthy tissues, with which they show excellent biocompatibility, and are biased towards tumors by targeting specific tissues through special endocytosis mechanisms. Thus, the use of these PENs may expand the scope of drug therapies while reducing the off-target effects. In this review, we summarize the fundamental features and bioactivities of PENs extracted from the grape, grapefruit, ginger, lemon, and broccoli and discuss the applications of these particles as therapeutics and nanocarriers.

Perspective: Milk microRNAs as Important Players in Infant Physiology and Development

Evolutionary selective pressure on lactation has resulted in milk that provides far more than simply essential nutrients, delivering a complex repertoire of agents from hormones to intact cells. Human infants are born with low barrier integrity of their gut, which means that many of the complex biopolymer components of milk enter and circulate in lymph and blood, reaching organs throughout the body. Due to this state of gut maturation, all components of milk are potentially part of the crosstalk between mother and infants. This article highlights the functions of milk's complex biopolymers, more specifically the potential role of microRNAs (miRNAs) contained in extracellular vesicles in human milk. miRNAs are key effectors in the regulation of many biological processes during early-age development, and consequently milk-sourced miRNAs must be considered to provide unique biological assets to the infant during breastfeeding. This article interprets the evidence of the potential action of human milk miRNAs on infant development, taking into account their abundance in milk based on the literature and current knowledge. Human milk miRNAs appear to influence lipid and glucose metabolism, gut maturation, neurogenesis, and immunity. We also show growing evidence that human milk miRNAs are epigenetic modulators that play a pivotal role in the regulation of tissue-specific gene expression throughout life. Furthermore, this article addresses the ongoing debate regarding the potential influence of human milk miRNAs on viral infection as a new research area. This article highlights that these bioactive molecules are now being incorporated into our overall understanding of nutrient needs for healthy infant development, preparing each individual infant to succeed as a healthy and protected adult throughout its life. In essence, miRNAs are a new language in the Rosetta stone of health that is mammalian lactation.

Maternal Microbiota, Early Life Colonization and Breast Milk Drive Immune Development in the Newborn

The innate immune system is the oldest protection strategy that is conserved across all organisms. Although having an unspecific action, it is the first and fastest defense mechanism against pathogens. Development of predominantly the adaptive immune system takes place after birth. However, some key components of the innate immune system evolve during the prenatal period of life, which endows the newborn with the ability to mount an immune response against pathogenic invaders directly after birth. Undoubtedly, the crosstalk between maternal immune cells, antibodies, dietary antigens, and microbial metabolites originating from the maternal microbiota are the key players in preparing the neonate’s immunity to the outer world. Birth represents the biggest substantial environmental change in life, where the newborn leaves the protective amniotic sac and is exposed for the first time to a countless variety of microbes. Colonization of all body surfaces commences, including skin, lung, and gastrointestinal tract, leading to the establishment of the commensal microbiota and the maturation of the newborn immune system, and hence lifelong health. Pregnancy, birth, and the consumption of breast milk shape the immune development in coordination with maternal and newborn microbiota. Discrepancies in these fine-tuned microbiota interactions during each developmental stage can have long-term effects on disease susceptibility, such as metabolic syndrome, childhood asthma, or autoimmune type 1 diabetes. In this review, we will give an overview of the recent studies by discussing the multifaceted emergence of the newborn innate immune development in line with the importance of maternal and early life microbiota exposure and breast milk intake.

Are Dietary Extracellular Vesicles Bioavailable and Functional in Consuming Organisms?

It has been well established that diet influences the health status of the consuming organism. Recently, extracellular vesicles (EVs) present in dietary sources are proposed to be involved in cross-species and kingdom communication. As EVs contain a lipid bilayer and carry bioactive cargo of proteins and nucleic acids, they are proposed to survive harsh degrading conditions of the gut and enter systemic circulation. Following the bioavailability, several studies have supported the functional role of dietary EVs in various tissues of the consuming organism. Simultaneously, multiple studies have refuted the possibility that dietary EVs mediate cross-species communication and hence the topic is controversial. The feasibility of the concept remains under scrutiny primarily owing to the lack of significant in vivo evidence to complement the in vitro speculations. Concerns surrounding EV stability in the harsh degrading gut environment, lack of mechanism explaining intestinal uptake and bioavailability in systemic circulation have impeded the acceptance of their functional role. This chapter discusses the current evidences that support dietary EV-based cross species communication and enlists several issues that need to be addressed in this field.

Eating microRNAs: pharmacological opportunities for cross-kingdom regulation and implications in host gene and gut microbiota modulation

Cross-kingdom communication via non-coding RNAs is a recent discovery. Exogenous microRNAs (exog-miRNAs) mainly enter the host via the diet. Generally considered unstable in the gastrointestinal tract, some exogenous RNAs may resist these conditions, especially if transported in extracellular vesicles. They could then reach the intestines and more probably exert a regulatory effect. We give an overview of recent discoveries concerning dietary miRNAs, possible ways of enhancing their resistance to food processing and gut conditions, their transport in extracellular vesicles (animal- and plant-origin) and possible biological effects on recipient cells after ingestion. We critically focus on what we believe are the most relevant data for future pharmacological development of dietary miRNAs as therapeutic agents. Finally, we discuss the miRNA-mediated cross-kingdom regulation between diet, host and the gut microbiota. We conclude that, despite many obstacles and challenges, extracellular miRNAs are serious candidates to be targeted pharmacologically for development of new therapeutic agents.

Bovine Milk-Derived Exosomes as a Drug Delivery Vehicle for miRNA-Based Therapy

MicroRNAs (miRNAs) are small non-coding RNAs with a known role as mediators of gene expression in crucial biological processes, which converts them into high potential contenders in the ongoing search for effective therapeutic strategies. However, extracellular RNAs are unstable and rapidly degraded, reducing the possibility of successfully exerting a biological function in distant target cells. Strategies aimed at enhancing the therapeutic potential of miRNAs include the development of efficient, tissue-specific and nonimmunogenic delivery methods. Since miRNAs were discovered to be naturally transported within exosomes, a type of extracellular vesicle that confers protection against RNase degradation and increases miRNA stability have been proposed as ideal delivery vehicles for miRNA-based therapy. Although research in this field has grown rapidly in the last few years, a standard, reproducible and cost-effective protocol for exosome isolation and extracellular RNA delivery is lacking. We aimed to evaluate the use of milk-derived extracellular vesicles as vehicles for extracellular RNA drug delivery. With this purpose, exosomes were isolated from raw bovine milk, combining ultracentrifugation and size exclusion chromatography (SEC) methodology. Isolated exosomes were then loaded with exogenous hsa-miR148a-3p, a highly expressed miRNA in milk exosomes. The suitability of exosomes as delivery vehicles for extracellular RNAs was tested by evaluating the absorption of miR-148a-3p in hepatic (HepG2) and intestinal (Caco-2) cell lines. The potential exertion of a biological effect by miR-148a-3p was assessed by gene expression analysis, using microarrays. Results support that bovine milk is a cost-effective source of exosomes which can be used as nanocarriers of functional miRNAs with a potential use in RNA-based therapy. In addition, we show here that a combination of ultracentrifugation and SEC technics improve exosome enrichment, purity, and integrity for subsequent use.

Exploration of microRNA profiles in human colostrum

Background

Colostrum is well known to have excellent nutritional value for newborns. The aim of this study was to investigate the dynamic expression pattern of microRNA in human colostrum and mature milk. Furthermore, we identified the specific microRNA in human colostrum and analyzed the regulatory function of human colostrum.

Methods

We collected breast milk samples from 18 lactating volunteers. The expression of microRNA in breast milk was detected by microarray analysis. The expression differences were characterized by log2FC (|log2fold change| >1.58) and associated P values (P<0.05). Furthermore, the prediction of microRNA targets, bioinformatics analysis and network generation were carried out using network database.

Results

Our results showed that during the human lactation process, the composition of microRNAs in human milk changes dynamically. Compared to the microRNA expression profile in human mature milk, the expression levels of 49 microRNAs were significantly different and 67 microRNAs were specifically expressed in human colostrum. Based on the results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, the predicted target mRNAs of the identified colostrum-specific microRNAs were involved in the regulation of distinct biological processes, such as signal transduction, positive regulation of GTPase activity, and protein phosphorylation. Moreover, the predicted mRNA targets were from large spectrums of signaling pathways, such as the MAPK, Ras, Hippo, Wnt, and mTOR signaling pathways, as well as the longevity regulating pathway.

Conclusions

Our study illuminates the landscape of microRNA expressions in human colostrum and mature milk, and emphasizes the value of microRNAs as nutritional additives in milk-related commercial products.

Evaluation of bovine milk extracellular vesicles for the delivery of locked nucleic acid antisense oligonucleotides

The natural capacity of extracellular vesicles (EVs) to transport their payload to recipient cells has raised big interest to repurpose EVs as delivery vehicles for xenobiotics. In the present study, bovine milk-derived EVs (BMEVs) were investigated for their potential to shuttle locked nucleic acid-modified antisense oligonucleotides (LNA ASOs) into the systemic circulation after oral administration. To this end, a broad array of analytical methods including proteomics and lipidomics were used to thoroughly characterize BMEVs. We found that additional purification by density gradients efficiently reduced levels of non-EV associated proteins. The potential of BMEVs to functionally transfer LNA ASOs was tested using advanced in vitro systems (i.e. hPSC-derived neurons and primary human cells). A slight increase in cellular LNA ASO internalization and target gene reduction was observed when LNA ASOs were delivered using BMEVs. When dosed orally in mice, only a small fraction (about 1% of total administered dose) of LNA ASOs was recovered in the peripheral tissues liver and kidney, however, no significant reduction in target gene expression (i.e. functional knockdown) was observed.

The Impact of Milk and Its Components on Epigenetic Programming of Immune Function in Early Life and Beyond: Implications for Allergy and Asthma

Specific and adequate nutrition during pregnancy and early life is an important factor in avoiding non-communicable diseases such as obesity, type 2 diabetes, cardiovascular disease, cancers, and chronic allergic diseases. Although epidemiologic and experimental studies have shown that nutrition is important at all stages of life, it is especially important in prenatal and the first few years of life. During the last decade, there has been a growing interest in the potential role of epigenetic mechanisms in the increasing health problems associated with allergic disease. Epigenetics involves several mechanisms including DNA methylation, histone modifications, and microRNAs which can modify the expression of genes. In this study, we focus on the effects of maternal nutrition during pregnancy, the effects of the bioactive components in human and bovine milk, and the environmental factors that can affect early life (i.e., farming, milk processing, and bacterial exposure), and which contribute to the epigenetic mechanisms underlying the persistent programming of immune functions and allergic diseases. This knowledge will help to improve approaches to nutrition in early life and help prevent allergies in the future.

Biological Characteristics and Roles of Noncoding RNAs in Milk-Derived Extracellular Vesicles

Extracellular vesicles (EVs) have diverse roles in the transport of proteins, lipids, and nucleic acids between cells, and they serve as mediators of intercellular communication. Noncoding RNAs (ncRNAs) that are present in EVs, including microRNAs, long noncoding RNAs, and circular RNAs, have been found to participate in complex networks of interactions and regulate a wide variety of genes in animals. Milk is an important source of nutrition for humans and other mammals. Evidence suggests that milk-derived EVs contain abundant ncRNAs, which are stable and can be transported to the offspring and other consumers. Current data suggest a strong link between milk EV ncRNAs and many biological processes, and these ncRNAs have been drawing increasing attention and might play an epigenetic regulatory role in recipients, though further research is still necessary to understand their precise roles. The present review introduces basic information about milk EV ncRNAs, summarizes their expression profiles, biological characteristics, and functions based on current knowledge, and discusses their biological roles, indeterminate issues, and perspectives. Our goal is to provide a deeper understanding of the physiological effects of milk EV ncRNAs on offspring and to provide a reference for future research in this field.

Circulating microRNAs in Breast Milk and Their Potential Impact on the Infant

MicroRNAs (MiRNAs) are small RNA molecules that can exert regulatory functions in gene expression. MiRNAs have been identified in diverse tissues and biological fluids, both in the context of health and disease. Breastfeeding has been widely recognized for its superior nutritional benefits; however, a number of bioactive compounds have been found to transcend these well-documented nutritional contributions. Breast milk was identified as a rich source of miRNAs. There has been increasing interest about their potential ability to transfer to the offspring as well as what their specific involvement is within the benefits of breast milk in the infant. In comparison to breast milk, formula milk lacks many of the benefits of breastfeeding, which is thought to be a result of the absence of some of these bioactive compounds. In recent years, the miRNA profile of breast milk has been widely studied, along with the possible transfer mechanisms throughout the infant's digestive tract and the role of miRNA-modulated genes and their potential protective and regulatory functions. Nonetheless, to date, the current evidence is not consistent, as many methodological limitations have been identified; hence, discrepancies exits about the biological functions of miRNAs. Further research is needed to provide thorough knowledge in this field.

Roles of Regulatory RNAs in Nutritional Control

Small RNAs (sRNAs), including microRNAs (miRNAs), are noncoding RNA (ncRNA) molecules involved in gene regulation. sRNAs play important roles in development; however, their significance in nutritional control and as metabolic modulators is still emerging. The mechanisms by which diet impacts metabolic genes through miRNAs remain an important area of inquiry. Recent work has established how miRNAs are transported in body fluids often within exosomes, which are small cell-derived vesicles that function in intercellular communication. The abundance of other recently identified ncRNAs and new insights regarding ncRNAs as dietary bioactive compounds could remodel our understanding about how foods impact gene expression. Although controversial, some groups have shown that dietary RNAs from plants and animals (i.e., milk) are functional in consumers. In the future, regulating sRNAs either directly through dietary delivery or indirectly by altered expression of endogenous sRNA may be part of nutritional interventions for regulating metabolism.

Evidence of transfer of miRNAs from the diet to the blood still inconclusive

MicroRNAs (miRNAs) are short, non-coding, single-strand RNA molecules that act as regulators of gene expression in plants and animals. In 2012, the first evidence was found that plant miRNAs could enter the bloodstream through the digestive tract. Since then, there has been an ongoing discussion about whether miRNAs from the diet are transferred to blood, accumulate in tissues, and regulate gene expression. Different research groups have tried to replicate these findings, using both plant and animal sources. Here, we review the evidence for and against the transfer of diet-derived miRNAs from plants, meat, milk and exosome and their assimilation and putative molecular regulation role in the consuming organism. Some groups using both miRNAs from plant and animal sources have claimed success, whereas others have not shown transfer. In spite of the biological barriers that may limit miRNA transference, several diet-derived miRNAs can transfer into the circulating system and targets genes for transcription regulation, which adds arguments that miRNAs can be absorbed from the diet and target specific genes by regulating their expression. However, many other studies show that cross-kingdom transfer of exogenous miRNAs appears to be insignificant and not biologically relevant. The main source of controversy in plant studies is the lack of reproducibility of the findings. For meat-derived miRNAs, studies concluded that the miRNAs can survive the cooking process; nevertheless, our evidence shows that the bovine miRNAs are not transferred to human bloodstream. The most important contributions and promising evidence in this controversial field is the transference of milk miRNAs in exosomes and the finding that plant miRNAs in beebread regulate honeybee caste development, and cause similar changes when fed to Drosophila. MiRNAs encapsulated in exosomes ensure their stability and resistance in the harsh conditions presented in milk, bloodstream, and gastrointestinaltract to reinforce the idea of transference. Regardless of the model organism, the idea of source of miRNAs, or the approach-bioinformatics or in vivo-the issue of transfer of miRNAs from the diet remains in doubt. Our understanding of the cross-kingdom talk of miRNAs needs more research to study the transfer of "xenomiRs" from different food sources to complement and expand what we know so far regarding the interspecies transfer of miRNAs.

Nutrition, Bioenergetics, and Metabolic Syndrome

According to the World Health Organization (WHO), the global nutrition report shows that whilst part of the world's population starves, the other part suffers from obesity and associated complications. A balanced diet counterparts these extreme conditions with the proper proportion, composition, quantity, and presence of macronutrients, micronutrients, and bioactive compounds. However, little is known on the way these components exert any influence on our health. These nutrients aiming to feed our bodies, our tissues, and our cells, first need to reach mitochondria, where they are decomposed into CO2 and H2O to obtain energy. Mitochondria are the powerhouse of the cell and mainly responsible for nutrients metabolism, but they are also the main source of oxidative stress and cell death by apoptosis. Unappropriated nutrients may support mitochondrial to become the Trojan horse in the cell. This review aims to provide an approach to the role that some nutrients exert on mitochondria as a major contributor to high prevalent Western conditions including metabolic syndrome (MetS), a constellation of pathologic conditions which promotes type II diabetes and cardiovascular risk. Clinical and experimental data extracted from in vitro animal and cell models further demonstrated in patients, support the idea that a balanced diet, in a healthy lifestyle context, promotes proper bioenergetic and mitochondrial function, becoming the best medicine to prevent the onset and progression of MetS. Any advance in the prevention and management of these prevalent complications help to face these challenging global health problems, by ameliorating the quality of life of patients and reducing the associated sociosanitary burden.

Cross-Kingdom Regulation by Plant microRNAs Provides Novel Insight into Gene Regulation

microRNAs (miRNAs) are well known as major players in mammalian and plant genetic systems that act by regulating gene expression at the post-transcriptional level. These tiny molecules can regulate target genes (mRNAs) through either cleavage or translational inhibition. Recently, the discovery of plant-derived miRNAs showing cross-kingdom abilities to regulate mammalian gene expression has prompted exciting discussions among researchers. After being acquired orally through the diet, plant miRNAs can survive in the digestive tract, enter the circulatory system, and regulate endogenous mRNAs. Here, we review current knowledge regarding the cross-kingdom mechanisms of plant miRNAs, related controversies, and potential applications of these miRNAs in dietary therapy, which will provide new insights for plant miRNA investigations related to health issues in humans.

Dietary impact of a plant-derived microRNA on the gut microbiome

Background:

Global estimations of 4 billion people living on plant-based diets signify tremendous diversity in plant consumption and their assorted miRNAs, which presents a challenging model to experimentally address how plant-based miRNAs impact the microbiome. Here we establish baseline gut microbiome composition for a mouse model deficient in the specific mammalian miR-146a shown to alter gut microbiomes. We then asses the effect on the gut microbiome when miR-146a-deficient mice are fed a transgenic plant-based diet expressing the murine-derived miR-146a. Mice deficient in miR-146a were maintained either on a baseline diet until 7 weeks of age (day 0) and then fed either vector or miR-146a-expressing plant-based diets for 21 days. The gut microbiomes of mice were examined by comparing the V4 region of 16S rRNA gene sequences of DNA isolated from fecal samples at days 0 (baseline diet) and 21 (vector or miR-146a expressing plant-based diets).

Results:

Beta-diversity analysis demonstrated that the transition from baseline chow to a plant-based diet resulted in significant longitudinal shifts in microbial community structure attributable to increased fiber intake. Bipartite network analysis suggests that miR-146a-deficient mice fed a plant diet rich in miR-146a have a microbiome population modestly different than mice fed an isogenic control plant diet deficient in miR-146a.

Conclusion:

A mouse diet composed of a transgenic plant expressing a mouse miR-146a may fine tune microbial communities but does not appear to have global effects on microbiome structure and composition.

Orally Administered Exosomes Suppress Mouse Delayed-Type Hypersensitivity by Delivering miRNA-150 to Antigen-Primed Macrophage APC Targeted by Exosome-Surface Anti-Peptide Antibody Light Chains

We previously discovered suppressor T cell-derived, antigen (Ag)-specific exosomes inhibiting mouse hapten-induced contact sensitivity effector T cells by targeting antigen-presenting cells (APCs). These suppressive exosomes acted Ag-specifically due to a coating of antibody free light chains (FLC) from Ag-activated B1a cells. Current studies are aimed at determining if similar immune tolerance could be induced in cutaneous delayed-type hypersensitivity (DTH) to the protein Ag (ovalbumin, OVA). Intravenous administration of a high dose of OVA-coupled, syngeneic erythrocytes similarly induced CD3⁺CD8⁺ suppressor T cells producing suppressive, miRNA-150-carrying exosomes, also coated with B1a cell-derived, OVA-specific FLC. Simultaneously, OVA-immunized B1a cells produced an exosome subpopulation, originally coated with Ag-specific FLC, that could be rendered suppressive by in vitro association with miRNA-150. Importantly, miRNA-150-carrying exosomes from both suppressor T cells and B1a cells efficiently induced prolonged DTH suppression after single systemic administration into actively immunized mice, with the strongest effect observed after oral treatment. Current studies also showed that OVA-specific FLC on suppressive exosomes bind OVA peptides suggesting that exosome-coating FLC target APCs by binding to peptide-Ag-major histocompatibility complexes. This renders APCs capable of inhibiting DTH effector T cells. Thus, our studies describe a novel immune tolerance mechanism mediated by FLC-coated, Ag-specific, miRNA-150-carrying exosomes that act on the APC and are particularly effective after oral administration.

Circulating microRNA trafficking and regulation: computational principles and practice

Rapid advances in genomics discovery tools and a growing realization of microRNA's implication in intercellular communication have led to a proliferation of studies of circulating microRNA sorting and regulation across cells and different species. Although sometimes, reaching controversial scientific discoveries and conclusions, these studies have yielded new insights in the functional roles of circulating microRNA and a plethora of analytical methods and tools. Here, we consider this body of work in light of key computational principles underpinning discovery of circulating microRNAs in terms of their sorting and targeting, with the goal of providing practical guidance for applications that is focused on the design and analysis of circulating microRNAs and their context-dependent regulation. We survey a broad range of informatics methods and tools that are available to the researcher, discuss their key features, applications and various unsolved problems and close this review with prospects and broader implication of this field.