A developing amount of research has demonstrated recently that some exogenous RNAs are known by a diversity of receptors in host eukaryotic cells and that these small non-coding RNAs can be moved across species boundaries to cause transboundary signal interference (Reniewicz et al. 2016). This form of cross-species communication that may aid common or harmful linkages between diverse creatures on earth, just as bacteria and hosts do (Liang et al. 2013). Exogenous miRNAs can be filled selectively into microvesicles and actively transported to destination cells after they enter the host body. Exogenous plant miRNAs can be expected by eating, allowing to studies, and can successively be found in the blood, organs, and tissues of experimental animals (Link et al. 2019).
Additionally, breast milk can also offer access to some plant miRNAs (Lukasik et al. 2017). Plant-derived miRNAs have the capability to enter the circulation and regulator the creation of endogenous mRNA via being absorbed by gastrointestinal cells through SITT1 (Zhang et al. 2012). Plant miRNAs have also been found in feces, blood, the digestive system, and organs ensuing the direct addition of plant RNA to food particles (Liang et al. 2014). Broccoli-derived miRNAs are impervious to typical food processing and digestive conditions (Chapado et al. 2021). Exogenous miRNAs have the capability to regulate receiver cell activity as well as target gene expression. Exogenous miRNAs look like to function equally to endogenous miRNAs once they are fused into the human body, aiding the host body control numerous aspects of life. Hepatic stellate cell activation is improved and irritation is reduced by soybean-derived gma-miR159a through preventing GSK3β-mediated NF-κB and transforming growth factor beta 1 (TGF-β1) pathways (Yu et al. 2021). Additionally, the current effort on the possible role of miRNAs on oral administration of human or mouse gene regulation has been ignited by their capability to regulate gene expression across kingdoms.
In mammals, blood levels of miRNAs, miR168a, miR2911, and miR156a are high, whereas serum levels of miR166a are uncertain. Unusually, miR2911 formed from honeysuckle displays antiviral effectiveness in cells and animals against SARS-CoV-2 and respiratory tract infection viruses (H1N1, H5N1, and H7N9) (Zhou et al. 2020a). Subsequently miR2911 is prepared from plant 26S ribosomal RNA and has a great GC content, oral treating and decoction do not cause it to alteration. Although pre-miRNAs like pre-miR168a and pre-miR156 are not found in cooked rice or mouse serum, advanced miR168a and miR156 levels are high. Additional exogenous miRNAs from honeysuckle, like miR166a and miR2910, are strictly destroyed by boiling. According to Chen et al. (2021), these results suggest that only mature miRNAs are engaged in the gut and that miRNAs formed from ribosome fragments may be more persistent and abundant subsequent decoction. Since these miRNAs made from ribosome remains lack precursor miRNAs, they are denoted to as unusual miRNAs. Future studies on these miRNAs must to focus extra on them. While miR156a, miR168, and miR166a can decline cytokine-induced monocyte adhesion and act as vasoprotective molecules by prompting low-density lipoprotein receptor adapter protein 1 (LDLRAP1) to treat cancer, other miRNAs have validated effective medicinal role, such as miR159, which overwhelms breast cancer by pointing the TCF7 gene (Chin et al. 2016; Hou et al. 2018). The key exogenous miRNAs in mammals and their regulation mechanisms are defined in the subgroups that follow.