The Stability of Medicinal Plant microRNAs in the Herb Preparation Process

Illuminating the pathogenic role of SARS-CoV-2: Insights into competing endogenous RNAs (ceRNAs) regulatory networks

The appearance of SARS-CoV-2 in 2019 triggered a significant economic and health crisis worldwide, with heterogeneous molecular mechanisms that contribute to its development are not yet fully understood. Although substantial progress has been made in elucidating the mechanisms behind SARS-CoV-2 infection and therapy, it continues to rank among the top three global causes of mortality due to infectious illnesses. Non-coding RNAs (ncRNAs), being integral components across nearly all biological processes, demonstrate effective importance in viral pathogenesis. Regarding viral infections, ncRNAs have demonstrated their ability to modulate host reactions, viral replication, and host-pathogen interactions. However, the complex interactions of different types of ncRNAs in the progression of COVID-19 remains understudied. In recent years, a novel mechanism of post-transcriptional gene regulation known as "competing endogenous RNA (ceRNA)" has been proposed. Long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and viral ncRNAs function as ceRNAs, influencing the expression of associated genes by sequestering shared microRNAs. Recent research on SARS-CoV-2 has revealed that disruptions in specific ceRNA regulatory networks (ceRNETs) contribute to the abnormal expression of key infection-related genes and the establishment of distinctive infection characteristics. These findings present new opportunities to delve deeper into the underlying mechanisms of SARS-CoV-2 pathogenesis, offering potential biomarkers and therapeutic targets. This progress paves the way for a more comprehensive understanding of ceRNETs, shedding light on the intricate mechanisms involved. Further exploration of these mechanisms holds promise for enhancing our ability to prevent viral infections and develop effective antiviral treatments.

Plant-derived exosome-like nanoparticles for microRNA delivery in cancer treatment

Plant-derived exosome-like nanoparticles (PELNs) are natural nanocarriers and effective delivery systems for plant microRNAs (miRNAs). These PELN-carrying plant miRNAs can regulate mammalian genes across species, thereby increasing the diversity of miRNAs in mammals and exerting multi-target effects that play a crucial role in diseases, particularly cancer. PELNs demonstrate exceptional stability, biocompatibility, and targeting capabilities that protect and facilitate the up-take and cross-kingdom communication of plant miRNAs in mammals. Primarily ingested and absorbed within the gastrointestinal tract of mammals, PELNs preferentially act on the intestine to regulate intestinal homeostasis through functional miRNA activity. The oncogenesis and progression of cancer are closely associated with disruptions in intestinal barriers, ecological imbalances, as well as secondary changes, such as abnormal inflammatory reactions caused by them. Therefore, it is imperative to investigate whether PELNs exert their anticancer effects by regulating mammalian intestinal homeostasis and inflammation. This review aims to elucidate the intrinsic crosstalk relationships and mechanisms of PELNs-mediated miRNAs in maintaining intestinal homeostasis, regulating inflammation and cancer treatment. Furthermore, serving as exceptional drug delivery systems for miRNAs molecules, PELNs offer broad prospects for future applications, including new drug research and development along with drug carrier selection within targeted drug delivery approaches for cancer therapy.

Plant-derived exosome-like nanovesicles: A novel nanotool for disease therapy

Exosomes are extracellular vesicles comprising bilayer phospholipid membranes and are secreted by eukaryotic cells. They are released via cellular exocytosis, contain DNA, RNA, proteins, and other substances, and participate in various cellular communications between tissues and organs. Since the discovery of exosomes in 1983, animal-derived exosomes have become a research focus for small-molecule drug delivery in biology, medicine, and other fields owing to their good biocompatibility and homing effects. Recent studies have found that plant-derived exosome-like nanovesicles (PELNVs) exhibit certain biological effects, such as anti-inflammatory and anti-tumor abilities, and have minimal toxic side effects. Because they are rich in active lipid molecules with certain pharmacological effects, PELNVs could be novel carriers for drug delivery. In this review, the biological formation and effects, isolation, and extraction of PELNVs, as well as characteristics of transporting drugs as carriers are summarized to provide new ideas and methods for future research on plant-derived exosome-like nanovesicles.

Advances in the Study of Plant-Derived Vesicle-Like Nanoparticles in Inflammatory Diseases

All humans are universally affected by inflammatory diseases, and there is an urgent need to identify new anti-inflammatory drugs with good therapeutic benefits and minimal side effects to the organism. Recently, it has been found that plant-derived vesicle-like nanoparticles (PDVLNs) have good biocompatibility, with their active ingredients exhibiting good therapeutic effects on inflammation. They can also be used as drug carriers for targeted delivery of anti-inflammatory drugs. Therefore, PDVLNs represent a popular research area for novel anti-inflammatory drugs. This paper details the origin, biological functions, isolation and purification, and identification of PDVLNs, as well as the therapeutic effects of their intrinsic bioactive components on inflammatory diseases. It also introduces their targets as drug carriers to facilitate the development and application of PDVLNs anti-inflammatory drugs.

Profile and potential bioactivity of the miRNome and metabolome expressed in Malva sylvestris L. leaf and flower

Malva sylvestris L. (common mallow) is a plant species widely used in phytotherapy and ethnobotanical practices since time immemorial. Characterizing the components of this herb might promote a better comprehension of its biological effects on the human body but also favour the identification of the molecular processes that occur in the plant tissues. Thus, in the present contribution, the scientific knowledge about the metabolomic profile of the common mallow was expanded. In particular, the phytocomplex of leaves and flowers from this botanical species and the extraction capacity of different concentrations of ethanol (i.e., 95%, 70%, 50%, and 0%; v/v in ddH2O) for it were investigated by spectrophotometric and chromatographic approaches. In detail, 95% ethanol extracts showed the worst capacity in isolating total phenols and flavonoids, while all the hydroalcoholic samples revealed a specific ability in purifying the anthocyanins. HPLC-DAD system detected and quantified 20 phenolic secondary metabolites, whose concentration in the several extracts depended on their own chemical nature and the percentage of ethanol used in the preparation. In addition, the stability of the purified phytochemicals after resuspension in pure ddH2O was also proved, considering a potential employment of them in biological/medical studies which include in vitro and in vivo experiments on mammalian models. Here, for the first time, the expressed miRNome in M. sylvestris was also defined by Next Generation Sequencing, revealing the presence of 33 microRNAs (miRNAs), 10 typical for leaves and 2 for flowers. Then, both plant and human putative mRNA targets for the detected miRNAs were predicted by bioinformatics analyses, with the aim to clarify the possible role of these small nucleic acids in the common mallow plant tissues and to try to understand if they could exert a potential cross-kingdom regulatory activity on the human health. Surprisingly, our investigations revealed that 19 miRNAs out of 33 were putatively able to modulate, in the plant cells, the expression of various chromosome scaffold proteins. In parallel, we found, in the human transcriptome, a total of 383 mRNAs involved in 5 fundamental mammalian cellular processes (i.e., apoptosis, senescence, cell-cycle, oxidative stress, and invasiveness) that theoretically could be bound and regulated by M. sylvestris miRNAs. The evidence collected in this work would suggest that the beneficial properties of the use of M. sylvestris, documented by the folk medicine, are probably linked to their content of miRNAs and not only to the action of phytochemicals (e.g., anthocyanins). This would open new perspectives about the possibility to develop gene therapies based on miRNAs isolated from medicinal plants, including M. sylvestris.

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.

Research progress on vesicles from Chinese medicinal herbs

Vesicles derived from Chinese medicinal herbs (VCMH) are nano-vesicular entities released by the cells of Chinese medicinal herbs. VCMHs have various biological effects and targeting characteristics, and their component chemicals and functional activities are closely related to the parent plant. VCMH differs from animal-derived vesicles in three ways: stability, specificity, and safety. There are a number of extraction and isolation techniques for VCMH, each with their own benefits and drawbacks, and there is no unified standard. When two or more approaches are used, high quantities of intact vesicles can be obtained more quickly and efficiently. The obtained VCMHs were systematically examined and evaluated. Firstly, they are generally saucer-shaped, cup-shaped or sphere, with particle size of 10-300 nm. Secondly, they contain lipids, proteins, nucleic acids and other active substances, and these components are an important part for intercellular information transfer. Finally, they mostly have good biocompatibility and low toxicity, with anti-inflammatory, antioxidant, anti-tumor and anti-fibrotic effects. As a new drug carrier, VCMHs have outstanding active targeting capabilities, and the capsule form can effectively preserve the drugs, considerably enhancing drug delivery efficiency and stability in vitro and in vivo. The modification of its vesicular structure by suitable physical or chemical means can further create more stable and precise drug carriers. This article reviews the extraction and purification techniques, activity evaluation and application of VCMH to provide information for further research and application of new active substances and targeted drug carriers.

Looking for Plant microRNAs in Human Blood Samples: Bioinformatics Evidence and Perspectives

Literature has proposed the existence of a cross kingdom regulation (CRK) between human and plants. In this context, microRNAs present in edible plants would be acquired through diet by the consumer's organism and transported via bloodstream to tissues, where they would modulate gene expression. However, the validity of this phenomenon is strongly debated; indeed, some scholars have discussed both the methodologies and the results obtained in previous works. To date, only one study has performed a bioinformatics analysis on small RNA-sequencing data for checking the presence of plant miRNAs (pmiRNAs) in human plasma. For that investigation, the lack of reliable controls, which led to the misidentification of human RNAs as pmiRNAs, has been deeply criticized. Thus, in the present contribution, we aim to demonstrate the existence of pmiRNAs in human blood, adopting a bioinformatics approach characterized by more stringent conditions and filtering. The information obtained from 380 experiments produced in 5 different next generation sequencing (NGS) projects was examined, revealing the presence of 350 circulating pmiRNAs across the analysed data set. Although one of the NGS projects shows results likely to be attributed to sample contamination, the others appear to provide reliable support for the acquisition of pmiRNAs through diet. To infer the potential biological activity of the identified pmiRNAs, we predicted their putative human mRNA targets, finding with great surprise that they appear to be mainly involved in neurogenesis and nervous system development. Unfortunately, no consensus was identified within the sequences of detected pmiRNAs, in order to justify their stability or capability to be preserved in human plasma. We believe that the issue regarding CKR still needs further clarifications, even if the present findings would offer a solid support that this hypothesis is not impossible.

Emerging evidence on the effects of plant-derived microRNAs in colorectal cancer: a review

Food nutrition and human health are still interesting international issues. Early detection, risk assessment and diet are vital to mitigate the load of intestinal diseases and enhance the quality of life. Plant-derived microRNAs could be transferred to mammalian organisms by cross-kingdom regulation which adjusts relevant target genes for their participation in the process of carcinogenesis. But the mechanism of plant-derived microRNAs in colorectal cancer is still unclear. This review aims to summarize the current pathways of plant-derived microRNAs in colorectal cancer including intestinal bacteria, the tumor microenvironment, plant active substances and protein, discuss the direct or indirect effects of plant-derived microRNAs on the occurrence and/or progression of colorectal cancer and explain why plant-derived microRNAs can be used as a potential anti-cancer agent. Moreover, the drawbacks of plant-derived microRNAs are also discussed in terms of both edible plants and synthetic delivery vectors for RNAi interference technology for human disease treatment. This review will provide a potential way for plant-derived microRNAs to target colorectal cancer.

MicroRNAs in Medicinal Plants

Medicinal plant microRNAs (miRNAs) are an endogenous class of small RNA central to the posttranscriptional regulation of gene expression. Biosynthetic research has shown that the mature miRNAs in medicinal plants can be produced from either the standard messenger RNA splicing mechanism or the pre-ribosomal RNA splicing process. The medicinal plant miRNA function is separated into two levels: (1) the cross-kingdom level, which is the regulation of disease-related genes in animal cells by oral intake, and (2) the intra-kingdom level, which is the participation of metabolism, development, and stress adaptation in homologous or heterologous plants. Increasing research continues to enrich the biosynthesis and function of medicinal plant miRNAs. In this review, peer-reviewed papers on medicinal plant miRNAs published on the Web of Science were discussed, covering a total of 78 species. The feasibility of the emerging role of medicinal plant miRNAs in regulating animal gene function was critically evaluated. Staged progress in intra-kingdom miRNA research has only been found in a few medicinal plants, which may be mainly inhibited by their long growth cycle, high demand for growth environment, immature genetic transformation, and difficult RNA extraction. The present review clarifies the research significance, opportunities, and challenges of medicinal plant miRNAs in drug development and agricultural production. The discussion of the latest results furthers the understanding of medicinal plant miRNAs and helps the rational design of the corresponding miRNA/target genes functional modules.

Type-2 diabetic rat heart: The effect of kolaviron on mTOR-1, P70S60K, PKC-α, NF-kB, SOD-2, NRF-2, eNOS, AKT-1, ACE, and P38 MAPK gene expression profile

It has been established that genetic factors partially contribute to type-2 diabetes and vascular disease development. This study determined the effect of kolaviron on the expression profile of genes associated with the insulin signaling pathway and involved in regulating glucose and lipid metabolism, oxidative stress, inflammation, vascular functions, pro-survival and the apoptosis pathway in the heart of type-2 diabetic rats. After induction and confirmation of type-2 diabetes seven days after, the rats were treated with kolaviron for twenty-eight days before being euthanized. Organs were harvested and stored at - 80 °C in a biofreezer. Total RNA was extracted from the ventricle, reverse transcribed to cDNA followed by a real-time quantitative polymerase chain reaction (RT-qPCR) analysis of the expression of mTOR-1, P70S60K, PKC-α, NF-kB, SOD-2, NRF-2, eNOS, AKT-1, ACE, p38 MAPK and the reference gene (GAPDH), after which they were normalized/standardized. The results show an increase in the relative mRNA expression of mTOR/P70S60K/PKCα /P38MAPK/NF-KB/ACE and a decrease in the relative mRNA expression of NRF2/SOD/AKT/eNOS in the heart of the diabetic rats. Nevertheless, kolaviron modulated the expression profile of these genes, which suggest a therapeutic effect and target for vascular dysfunction and complications in type-2 diabetes through the activation of the NRF-2/AKT-1/eNOS signaling pathway and suppression of the NF-kB/PKC signaling pathway.

Stress-induced miRNAs isolated from wheat have a unique therapeutic potential in ultraviolet-stressed human keratinocyte cells

Increasing evidence supports the existence of cross-kingdom gene regulation. However, the therapeutic potential of stress-specific plant miRNAs and their role in UV-related pathologies in human tissue remain largely unexplored. The aim of this study was to investigate the therapeutic potential and mechanisms of action of stress-induced miRNA cocktails (SI-WmiRs) from Einkorn wheat (Triticum monococcum L.) on human keratinocyte (HaCaT) cells exposed to a high dose of UV-B radiation. We used a biofactory approach and irradiated wheatgrass with UV-C for 240 min to obtain the specific SI-WmiRs that wheat produces to recover from UV stress. We followed the plant with molecular and biochemical analyses and extracted our SI-WmiRs at the most appropriate time (0 h and 6 h after UV-C application). Then, we applied the SI-WmiR cocktail to HaCaT cells exposed to high-dose of UV-B radiation. Our results show that UV-B radiation induced lipid peroxidation and DNA damage, as demonstrated by increased malondialdehyde (MDA) levels and changes in the RAPD band profile, respectively. UV stress also impaired IL6/JAK2/STAT3 signalling and activated the inflammatory mediators IL6 and TNF-α in HaCaT cells, leading to significant induction of apoptotic cell death. We found that SI-WmiR transfection prevents lipid peroxidation and oxidative stress-related DNA damage by increasing antioxidant (CuZn-SOD, Mn-SOD) and DNA repair (EXO1, SMUG1 and XRCC3) gene expression. In addition, SI-WmiRs regulated IL6/JAK2/STAT3 signalling by reducing JAK2 and STAT3 gene expression and phosphorylated protein levels compared to the control treatments. Moreover, SI-WmiRs inhibited pro-apoptotic BAX, Caspase 3 and Caspase 8 gene expression and protein levels to prevent apoptosis of UV-stressed HaCaT cells. Our results demonstrate that stress-induced wheat miRNAs produced using a biofactory approach have strong potential as a novel and effective alternative therapy for UV stress-related skin damage.

Exosomes as New Biomarkers and Drug Delivery Tools for the Prevention and Treatment of Various Diseases: Current Perspectives

Exosomes are nano-sized vesicles secreted by most cells that contain a variety of biological molecules, such as lipids, proteins and nucleic acids. They have been recognized as important mediators for long-distance cell-to-cell communication and are involved in a variety of biological processes. Exosomes have unique advantages, positioning them as highly effective drug delivery tools and providing a distinct means of delivering various therapeutic agents to target cells. In addition, as a new clinical diagnostic biomarker, exosomes play an important role in many aspects of human health and disease, including endocrinology, inflammation, cancer, and cardiovascular disease. In this review, we summarize the development of exosome-based drug delivery tools and the validation of novel biomarkers, and illustrate the role of exosomes as therapeutic targets in the prevention and treatment of various diseases.

Therapeutic Properties of Edible Mushrooms and Herbal Teas in Gut Microbiota Modulation

Edible mushrooms are functional foods and valuable but less exploited sources of biologically active compounds. Herbal teas are a range of products widely used due to the therapeutic properties that have been demonstrated by traditional medicine and a supplement in conventional therapies. Their interaction with the human microbiota is an aspect that must be researched, the therapeutic properties depending on the interaction with the microbiota and the consequent fermentative activity. Modulation processes result from the activity of, for example, phenolic acids, which are a major component and which have already demonstrated activity in combating oxidative stress. The aim of this mini-review is to highlight the essential aspects of modulating the microbiota using edible mushrooms and herbal teas. Although the phenolic pattern is different for edible mushrooms and herbal teas, certain non-phenolic compounds (polysaccharides and/or caffeine) are important in alleviating chronic diseases. These specific functional compounds have modulatory properties against oxidative stress, demonstrating health-beneficial effects in vitro and/or In vivo. Moreover, recent advances in improving human health via gut microbiota are presented. Plant-derived miRNAs from mushrooms and herbal teas were highlighted as a potential strategy for new therapeutic effects.

A Timely Review of Cross-Kingdom Regulation of Plant-Derived MicroRNAs

MicroRNAs (miRNAs) belong to a class of non-coding RNAs that suppress gene expression by complementary oligonucleotide binding to the sites in target messenger RNAs. Numerous studies have demonstrated that miRNAs play crucial role in virtually all cellular processes of both plants and animals, such as cell growth, cell division, differentiation, proliferation and apoptosis. The study of rice MIR168a has demonstrated for the first time that exogenous plant MIR168a influences cholesterol transport in mice by inhibiting low-density lipoprotein receptor adapter protein 1 expression. Inspired by this finding, the cross-kingdom regulation of plant-derived miRNAs has drawn a lot of attention because of its capability to provide novel therapeutic agents in the treatment of miRNA deregulation-related diseases. Notably, unlike mRNA, some plant miRNAs are robust because of their 3′ end modification, high G, C content, and the protection by microvesicles, miRNAs protein cofactors or plant ingredients. The stability of these small molecules guarantees the reliability of plant miRNAs in clinical application. Although the function of endogenous miRNAs has been widely investigated, the cross-kingdom regulation of plant-derived miRNAs is still in its infancy. Herein, this review summarizes the current knowledge regarding the anti-virus, anti-tumor, anti-inflammatory, anti-apoptosis, immune modulation, and intestinal function regulation effects of plant-derived miRNAs in mammals. It is expected that exploring the versatile role of plant-derived miRNAs may lay the foundation for further study and application of these newly recognized, non-toxic, and inexpensive plant active ingredients.

Strawberry-Derived Exosome-Like Nanoparticles Prevent Oxidative Stress in Human Mesenchymal Stromal Cells

Plant-derived exosome-like nanovesicles (EPDENs) have recently been isolated and evaluated as potential bioactive nutraceutical biomolecules. It has been hypothesized that EPDENs may exert their activity on mammalian cells through their specific cargo. In this study, we isolated and purified EPDENs from the strawberry juice of Fragaria x ananassa (cv. Romina), a new cultivar characterized by a high content of anthocyanins, folic acid, flavonols, and vitamin C and an elevated antioxidant capacity. Fragaria-derived EPDENs were purified by a series of centrifugation and filtration steps. EPDENs showed size and morphology similar to mammalian extracellular nanovesicles. The internalization of Fragaria-derived EPDENs by human mesenchymal stromal cells (MSCs) did not negatively affect their viability, and the pretreatment of MSCs with Fragaria-derived EPDENs prevented oxidative stress in a dose-dependent manner. This is possibly due to the presence of vitamin C inside the nanovesicle membrane. The analysis of EPDEN cargo also revealed the presence of small RNAs and miRNAs. These findings suggest that Fragaria-derived EPDENs may be considered nanoshuttles contained in food, with potential health-promoting activity.

Plant miR171 modulates mTOR pathway in HEK293 cells by targeting GNA12

Plant microRNAs have shown the capacity to regulate mammalian systems. The potential bioactivity of miR171vr, an isoform of the plant miR171, on human embryonic kidney 293 (HEK293) cells was investigated. Bioinformatics simulations revealed that human G protein subunit alpha 12 (GNA12) transcript could represent an excellent target for miR171vr. To confirm this prediction, in vitro experiments were performed using a synthetic microRNA designed on miR171vr sequence. MiR-treated cells showed a significant decrease of GNA12 mRNA and protein levels, confirming the putative cross-kingdom interaction. In addition, miR171vr determined the modulation of GNA12 downstream signaling factors, including mTOR, as expected. Finally, the effect of the plant miRNA on HEK293 cell growth and its stability in presence of several stressors, such as those miming digestive processes and procedures for preparing food, were evaluated. All this preliminary evidence would suggest that miR171vr, introduced by diet or as supplement in gene therapies, could potentially influence human gene expression, especially for treating disorders where GNA12 is over-expressed (i.e. oral cancer, breast and prostate adenocarcinoma) or mTOR kinase is down-regulated (e.g. obesity, type 2 diabetes, neurodegeneration).

Identification and Investigation of miRNAs From Gastrodia elata Blume and Their Potential Function

Gastrodia elata Blume (G. elata) is a valuable traditional Chinese medicine with neuroprotection, anti-inflammatory, and immune regulatory functions. MicroRNAs (miRNA) is a kind of endogenous noncoding small RNAs that plays distinctly important roles for gene regulation of organisms. So far, the research on G. elata is mainly focused on the pharmacological functions of the natural chemical ingredients, and the function of G. elata miRNA remains unknown. In this study, 5,718 known miRNAs and 38 novel miRNAs were identified by high-throughput sequencing from G. elata. Based on GO and KEGG analysis, we found that the human genes possibly regulated by G. elata miRNAs were related to the cell cycle, immune regulation, intercellular communication, etc. Furthermore, two novel miRNAs as Gas-miR01 and Gas-miR02 have stable and high expression in the medicinal tissues of G. elata. Further bioinformatics prediction showed that both Gas-miR01 and Gas-miR02 could target Homo sapiens A20 gene, furthermore, the dual-luciferase reporter gene assay and Western Blotting verified the interaction of Gas-miR01 or Gas-miR02 with A20. These evidences suggested that G. elata-unique miRNAs might be involved in certain physiological processes. The animal experiment showed that Gas-miR01 and Gas-miR02 could be detected in some tissues of mice by intragastric administration; meanwhile, the A20 expression in some tissues of mice was downregulated. These results supported for the functional study of G. elata miRNAs.

Soybean-derived miRNAs specifically inhibit proliferation and stimulate apoptosis of human colonic Caco-2 cancer cells but not normal mucosal cells in culture

MicroRNAs (miRNAs) are important regulators of gene expression in eukaryotes. Studies have shown that plant-derived miRNAs can be absorbed through diets and regulate gene expression in mammals. Although soybean-derived miRNAs have been reported, their biological functions are still unclear. In this study, we found that soybean-derived small RNAs (sRNAs) significantly inhibited the proliferation and stimulated the apoptosis of Caco-2 cells. Bioinformatics analysis indicated that the target gene set of soybean miRNAs was extensively enriched in cancer pathways. Besides, we obtained 8 target genes, including Transcription factor 7 (TCF7), associated with colon cancer through prediction. Further studies showed that gma-miR159a inhibited the proliferation of Caco-2 cells and played an important role in the inhibitory effect of sRNAs by inhibiting TCF7 protein, which are upregulated in colon cancer cells but not normal mucosal cells in culture. These findings provide a novel molecular mechanism of soybean-derived miRNAs for potential application in tumor prevention.

Stability and absorption mechanism of typical plant miRNAs in an in vitro gastrointestinal environment: basis for their cross-kingdom nutritional effects

Plant miRNAs, a group of 19-24 nt noncoding RNAs from plant foods, were recently found to have immunomodulatory and nutritional effects on mammalian and human bodies. However, how the miRNAs survive gastrointestinal (GI) environment and how the stable miRNAs are absorbed, which serve the basis for their biological functions, were not unraveled. Here, we investigated the stabilities of six typical plant miRNAs in simulated gastric and intestinal environments, and the absorption mechanisms by Caco-2 cells. The results showed that the miRNAs can survive the environment with certain concentrations. The mixture of food ingredients enhanced the stabilities of the plant miRNAs in the gastric conditions, while 2'-O-methyl modification protects the miRNAs in intestinal juice. The stabilities of the miRNAs vary significantly in the environment and are related to their secondary structures. The stable plant miRNAs can be absorbed by Caco-2 cells via clathrin- and caveolin-mediated endocytosis. Uptake of the miRNAs was sequence dependent, facilitated by NACh and TLR9, two typical receptors on cell membrane. The results suggest that some of plant miRNAs are stable in the mimic GI environment and can be absorbed by Caco-2 cells, underlying the potential of their cross-kingdom regulation effects.

Effect of microvesicles from Moringa oleifera containing miRNA on proliferation and apoptosis in tumor cell lines

Human microvesicles are key mediators of cell-cell communication. Exosomes function as microRNA transporters, playing a crucial role in physiological and pathological processes. Plant microvesicles (MVs) display similar features to mammalian exosomes, and these MVs might enhance plant microRNA delivery in mammals. Considering that plant microRNAs have been newly identified as bioactive constituents in medicinal plants, and that their potential role as regulators in mammals has been underlined, in this study, we characterized MVs purified from Moringa oleifera seeds aqueous extract (MOES MVs) and used flow cytometry methods to quantify the ability to deliver their content to host cells. The microRNAs present in MOES MVs were characterized, and through a bioinformatic analysis, specific human apoptosis-related target genes of plant miRNAs were identified. In tumor cell lines, MOES MVs treatment reduced viability, increased apoptosis levels associated with a decrease in B-cell lymphoma 2 protein expression and reduced mitochondrial membrane potential. Interestingly, the effects observed with MOES MVs treatment were comparable to those observed with MOES treatment and transfection with the pool of small RNAs isolated from MOES, used as a control. These results highlight the role of microRNAs transported by MOES MVs as natural bioactive plant compounds that counteract tumorigenesis.

Extracellular Vesicles-Connecting Kingdoms

It is known that extracellular vesicles (EVs) are shed from cells of almost every type of cell or organism, showing their ubiquity in all empires of life. EVs are defined as naturally released particles from cells, delimited by a lipid bilayer, and cannot replicate. These nano- to micrometer scaled spheres shuttle a set of bioactive molecules. EVs are of great interest as vehicles for drug targeting and in fundamental biological research, but in vitro culture of animal cells usually achieves only small yields. The exploration of other biological kingdoms promises comprehensive knowledge on EVs broadening the opportunities for basic understanding and therapeutic use. Thus, plants might be sustainable biofactories producing nontoxic and highly specific nanovectors, whereas bacterial and fungal EVs are promising vaccines for the prevention of infectious diseases. Importantly, EVs from different eukaryotic and prokaryotic kingdoms are involved in many processes including host-pathogen interactions, spreading of resistances, and plant diseases. More extensive knowledge of inter-species and interkingdom regulation could provide advantages for preventing and treating pests and pathogens. In this review, we present a comprehensive overview of EVs derived from eukaryota and prokaryota and we discuss how better understanding of their intercommunication role provides opportunities for both fundamental and applied biology.

Host Plant-Derived miRNAs Potentially Modulate the Development of a Cosmopolitan Insect Pest, Plutella xylostella

Plant microRNAs (miRNAs) have recently been reported to be involved in the cross-kingdom regulation of specific cellular and physiological processes in animals. However, little of this phenomenon is known for the communication between host plant and insect herbivore. In this study, the plant-derived miRNAs in the hemolymph of a cruciferous specialist Plutella xylostella were identified by small RNAs sequencing. A total of 39 miRNAs with typical characteristics of plant miRNAs were detected, of which 24 had read counts ≥ 2 in each library. Three plant-derived miRNAs with the highest read counts were validated, and all of them were predicted to target the hemocyanin domains-containing genes of P. xylostella. The luciferase assays in the Drosophila S2 cell demonstrated that miR159a and novel-7703-5p could target BJHSP1 and PPO2 respectively, possibly in an incomplete complementary pairing mode. We further found that treatment with agomir-7703-5p significantly influenced the pupal development and egg-hatching rate when reared on the artificial diet. The developments of both pupae and adults were severely affected upon their transfer to Arabidopsis thaliana, but this might be independent of the cross-kingdom regulation of the three plant-derived miRNAs on their target genes in P. xylostella, based on expression analysis. Taken together, our work reveals that the plant-derived miRNAs could break the barrier of the insect mid-gut to enter the circulatory system, and potentially regulate the development of P. xylostella. Our findings provide new insights into the co-evolution of insect herbivore and host plant, and novel direction for pest control using plant-derived miRNAs.

Atropa belladonna Expresses a microRNA (aba-miRNA-9497) Highly Homologous to Homo sapiens miRNA-378 (hsa-miRNA-378); both miRNAs target the 3'-Untranslated Region (3'-UTR) of the mRNA Encoding the Neurologically Relevant, Zinc-Finger Transcription Factor ZNF-691

Recent advances in ethnobotanical and neurological research indicate that ingested plants from our diet may not only be a source of nutrition but also a source of biologically relevant nucleic-acid-encoded genetic information. A major source of RNA-encoded information from plants has been shown to be derived from small non-coding RNAs (sncRNAs) such as microRNAs (miRNAs) that can transfer information horizontally between plants and humans. In human hosts, the 3'-untranslated region (3'-UTR) of messenger RNAs (mRNAs) is targeted by these miRNAs to effectively down-regulate expression of that mRNA target in the host CNS. In this paper, we provide evidence that the Atropa belladonna aba-miRNA-9497 (miRBase conserved ID: bdi-miRNA-9497) is highly homologous to the CNS-abundant Homo sapiens miRNA-378 (hsa-miRNA-378) and both target the zinc-finger transcription factor ZNF-691 mRNA 3'-UTR to down-regulate ZNF-691 mRNA abundance. We speculate that the potent neurotoxic actions of the multiple tropane alkaloids of Atropa belladonna may be supplemented by the neuroregulatory actions of aba-miRNA-9497 on ZNF-691, and this may be followed by the modulation in the expression of ZNF-691-sensitive genes. This is the first example of a human brain-enriched transcription factor, ZNF-691, targeted and down-regulated by a naturally occurring plant microRNA, with potential to modulate gene expression in the human CNS and thus contribute to the neurotoxicological-and-psychoactive properties of the Atropa belladonna species of the deadly nightshade Solanaceae family.