Delineating effect of corn microRNAs and matrix, ingested as whole food, on gut microbiota in a rodent model

miRNA and DNA analysis by negative ion electron transfer dissociation and infrared multiple-photon dissociation mass spectrometry

BACKGROUND

The use of simple and hybrid fragmentation techniques for the identification of molecules in tandem mass spectrometry provides different and complementary information on the structure of molecules. Nevertheless, these techniques have not been as widely explored for oligonucleotides as for peptides or proteins. The analysis of microRNAs (miRNAs) warrants special attention, given their regulatory role and their relationship with several diseases. The application of different fragmentation techniques will be very interesting for their identification.

RESULTS

Four synthetic miRNAs and a DNA sequence were fragmented in an ESI-FT-ICR mass spectrometer using both simple and hybrid fragmentation techniques: CID, nETD followed by CID, IRMPD, and, for the first time, nETD in combination with IRMPD. The main fragmentation channel was base loss. The use of nETD-IRMPD resulted in d/z, a/w, and c/y ions at higher intensities. Moreover, nETD-IRMPD provided high sequence coverage and low internal fragmentation. Native MS analysis revealed that only miR159 and the DNA sequence formed stable dimers under physiological ionic strength. The use of organic co-solvents or additives resulted in a lower sequence coverage due to lesser overall ionization efficiency.

NOVELTY

This work demonstrates that the combination of nETD and IRMPD for miRNA fragmentation constitutes a suitable alternative to common fragmentation methods. This strategy resulted in efficient fragmentation of [miRNA]5- using low irradiation times and fewer internal fragments while ensuring a high sequence coverage. Moreover, given that such low charge states predominate upon spraying in physiological-like conditions, native MS can be applied for obtaining structural information at the same time.

Evidence of Cross-Kingdom Gene Regulation by Plant MicroRNAs and Possible Reasons for Inconsistencies

The debate on whether cross-kingdom gene regulation by orally acquired plant miRNAs is possible has been ongoing for nearly 10 years without a conclusive answer. In this study, we categorized plant miRNAs into different groups, namely, extracellular vesicle (EV)-borne plant miRNAs, extracted plant miRNAs, herbal decoction-borne plant miRNAs, synthetic plant miRNA mimics, and plant tissue/juice-borne plant miRNAs. This categorization aimed to simplify the analysis and address the question more specifically. Our evidence suggests that EV-borne plant miRNAs, extracted plant miRNAs, herbal decoction-borne plant miRNAs, and synthetic plant miRNA mimics consistently facilitate cross-kingdom gene regulation. However, the results regarding the cross-kingdom gene regulation by plant tissue- and juice-borne plant miRNAs are inconclusive. This inconsistency may be due to variations in study methods, a low absorption rate of miRNAs and the selective absorption of plant miRNAs in the gastrointestinal tract. Overall, it is deduced that cross-kingdom gene regulation by orally acquired plant miRNAs can occur under certain circumstances, depending on factors such as the types of plant miRNAs, the delivery mechanism, and their concentrations in the plant.

A New Frontier in Phytotherapy: Harnessing the Therapeutic Power of Medicinal Herb-derived miRNAs

Medicinal herbs have been utilized in the treatment of various pathologic conditions, including neoplasms, organ fibrosis, and diabetes mellitus. However, the precise pharmacological actions of plant miRNAs in animals remain to be fully elucidated, particularly in terms of their therapeutic efficacy and mechanism of action. In this review, some important miRNAs from foods and medicinal herbs are presented. Plant miRNAs exhibit a range of pharmacological properties, such as anti-cancer, anti-fibrosis, anti-viral, anti-inflammatory effects, and neuromodulation, among others. These results have not only demonstrated a cross-species regulatory effect, but also suggested that the miRNAs from medicinal herbs are their bioactive components. This shows a promising prospect for plant miRNAs to be used as drugs. Here, the pharmacological properties of plant miRNAs and their underlying mechanisms have been highlighted, which can provide new insights for clarifying the therapeutic mechanisms of medicinal herbs and suggest a new way for developing therapeutic drugs.

Role of MicroRNAs in Dietary Interventions for Obesity and Obesity-Related Diseases

Obesity and related metabolic syndromes pose a serious threat to human health and quality of life. A proper diet is a safe and effective strategy to prevent and control obesity, thus maintaining overall health. However, no consensus exists on the connotations of proper diet, and it is attributed to various factors, including "nutritional dark matter" and the "matrix effect" of food. Accumulating evidence confirms that obesity is associated with the in vivo levels of miRNAs, which serve as potential markers and regulatory targets for obesity onset and progression; food-derived miRNAs can regulate host obesity by targeting the related genes or gut microbiota across the animal kingdom. Host miRNAs mediate food nutrient-gut microbiota-obesity interactions. Thus, miRNAs are important correlates of diet and obesity onset. This review outlines the recent findings on miRNA-mediated food interventions for obesity, thereby elucidating their potential applications. Overall, we provide new perspectives and views on the evaluation of dietary nutrition, which may bear important implications for dietary control and obesity prevention.

MiRNAs Expression Modulates Osteogenesis in Response to Exercise and Nutrition

In recent years, many articles have been published describing the impact of physical activity and diet on bone health. This review has aimed to figure out the possible epigenetic mechanisms that influence bone metabolism. Many studies highlighted the effects of macro and micronutrients combined with exercise on the regulation of gene expression through miRs. The present review will describe how physical activity and nutrition can prevent abnormal epigenetic regulation that otherwise could lead to bone-metabolism-related diseases, the most significant of which is osteoporosis. Nowadays, it is known that this effect can be carried out not only by endogenously produced miRs, but also through those intakes through the diet. Indeed, they have also been found in the transcriptome of animals and plants, and it is possible to hypothesise an interaction between miRNAs produced by different kingdoms and epigenetic influences on human gene expression. In particular, the key to the activation pathways triggered by diet and physical activity appears to be the activation of Runt-related transcription factor 2 (RUNX2), the expression of which is regulated by several miRs. Among the main miRs involved are exercise-induced miR21 and 21-5p, and food-induced miR 221-3p and 222-3p.

Insights into Health-Promoting Effects of Plant MicroRNAs: A Review

Plant-derived microRNAs (miRNAs) play a significant role in human health and are "dark nutrients", as opposed to traditional plant nutrients, as well as important components of food diversification. Studies have revealed that multiple plant-derived miRNA pathways affect human health. First, plant miRNAs regulate plant growth and development and accumulation of metabolites, which alters the food quality and thus indirectly interferes with the health of the host. Moreover, when absorbed in vivo, some miRNAs may target the host cell mRNAs to affect protein expression. In addition, plant miRNAs target and reshape the human gut microbiota (GM), which interferes with the physiology and metabolism of the host. Therefore, miRNAs play a significant role in the cross-kingdom communication of plants, GM, and the host and in maintaining a balance of the three. Future contributions of plant miRNAs can bring new perspectives and opportunities to better understand food nutrition and health care research, which will facilitate the right exploitation of plant resources.