Nutritive implications of dietary microRNAs: facts, controversies, and perspectives

Two Worlds Colliding: The Interplay Between Natural Compounds and Non-Coding Transcripts in Cancer Therapy

Cancer is a devastating disease and has recently become the leading cause of death in western countries, representing an immense public health burden. When it comes to cancer treatment, chemotherapy is one of the main pillars, especially for advanced stage tumors. Over the years, natural compounds have emerged as one of the most valuable resources for new chemotherapies. It is estimated that more than half of the currently used chemotherapeutic agents are derived from natural compounds. Usually, natural compounds are discovered empirically and an important limitation of introducing new anti-cancer natural products is lack of knowledge with regard to their mechanism of action. Recent data has proven that several natural compounds may function via modulating the expression and function of non-coding RNAs (ncRNAs). NcRNAs are a heterogenous class of RNA molecules which are usually not translated into proteins but have an important role in gene expression regulation and are involved in multiple tumorigenic processes, including response/resistance to pharmacotherapy. In this review, we will discuss how natural compounds function via ncRNAs while summarizing the available data regarding their effects on over 15 types of cancer. Moreover, we will critically analyze the current advances and limitations in understanding the way natural compounds exert these health-promoting effects by acting on ncRNAs. Finally, we will propose several hypotheses that may open new avenues and perspectives regarding the interaction between natural compounds and ncRNAs, which could lead to improved natural compound-based therapeutic strategies in cancer.

Dietary microRNAs: Current status and perspective in food science

Food safety and health conditions are global issues that are primarily caused by insufficient nutrition or contaminated food, which have enormous social, economic, and public health implications. Foodomics study mainly involves nutrigenomics, nutrigenetics, and nutritional epigenetics, which help in finding the correlation between genetic variation and nutrient-driven epigenetic alterations that are suggested as a primary challenge to nutritional needs. Micro-ribonucleic acids (miRNAs) are non-coding RNA molecules that have recently gained in popularity as a result of their critical roles in gene regulation and nutritional studies. In this commentary, the relevance of miRNAs to human nutrition is discussed. This study emphasizes the importance of dietary miRNAs based on numerous independent studies, which have explained the unique characteristics of dietary miRNAs in terms of gene expression regulation mechanism. There is an urgent requirement of measurement techniques to detect miRNA in food and evolutionary samples. These techniques may be helpful to find even low levels of miRNAs because of their high susceptibility and selectivity. There is a desperate requisite to evaluate the impact of dietary supplement compounds on circulating and tissue miRNAs. Food science studies in humans may aid in the identification of novel biomarkers and other necessary mode of action of certain dietary compounds, with the goal of facilitating how nutrients and bioactive components can influence miRNAs and enforce biological effects. PRACTICAL APPLICATIONS: Dietary microRNAs may be helpful to find even the low levels of miRNAs due to their high susceptibility and selectivity. There is also desperate need to evaluate the impact of dietary supplement compounds effect on circulating and tissue miRNAs. There is also requirement for new analytical tools to study the role of gene regulations and nutrition in different diseases. The quality of dietary miRNAs should be investigated, particularly the exogenous types which are used as high doses in food supplements. It would also be of great interest to use antagomir technology in food science research, in addition to omics technology. Dietary miRNAs may also aid in the identification of novel biomarkers. These are some of the practical applications of dietary miRNAs.

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.

Dietary Soy Protein Isolate Attenuates Intestinal Immunoglobulin and Mucin Expression in Young Mice Compared with Casein

Dietary protein sources have profound effects on children and young animals, and are important for the gut barrier function and immune resilience. Milk and soy are the main sources of protein for children and young animals after weaning. The objective of this study was to compare the effects of dairy and soy proteins on the intestinal barrier in early development. Weanling C57BL/6 mice were fed AIN-93G diets prepared with casein or soy protein isolate (SPI) for 21 days. Compared with those fed with the casein diet, mice fed with the SPI diet did not change their body weight and organ coefficients, but increased their feed intake and ratio of feed to gain. SPI lowered the level of luminal secretory immunoglobulin A (SIgA) and downregulated the levels of IL-4, IL-13, polymeric immunoglobulin receptor (Pigr), Janus kinase 1 (Jak1), signal transducer and activator of transcription 6 (Stat6), and transforming growth factor-β (Tgfb) in the mouse ileum. Western blotting of ileal proteins confirmed that SPI suppressed the activation of the JAK1/STAT6 signaling pathway. Furthermore, SPI attenuated intestinal mucin production, as demonstrated by the decreased numbers of intestinal goblet cells and the reduced relative expression levels of mucin 1 (Muc1), mucin 2 (Muc2), trefoil factor 3 (Tff3), glucose-regulated protein 94 (Grp94), and anterior gradient homolog 2 (Agr2). The results indicated that the SPI diet could attenuate mouse intestinal immunity, as demonstrated by decreased SIgA and mucin production in the intestine. Therefore, we suggest that our findings should be of consideration when SPI or casein are used as dietary protein sources.