RNA, a crucial molecule in protein synthesis and gene expression regulation, plays an essential role in organisms. RNA modifications, acting as epigenetic marks, subtly adjust the structure, stability, and function of RNA, thereby regulating gene expression and exerting profound effects on cellular functions and organismal health. These natural modifications, together with RNA editing that alters nucleotide sequence of mRNA, constitute the epitranscriptome, which is vital for cellular metabolism. With the rapid advancement of biotechnology, RNA-based therapies and technologies have emerged as a frontier in biotech research. Various RNA drugs, including small interfering RNA (siRNA), antisense oligonucleotides (ASO), mRNA vaccines, and the small guide RNA (sgRNA) required for CRISPR gene editing, have been continuously developed. It has been widely demonstrated that RNA modifications can alter the physicochemical properties of RNA, enhance resistance to nucleases, reduce immunogenicity, and optimize in vivo functionality, leading to their extensive application in RNA-related biotechnologies. Furthermore, the variety of RNA modifications has expanded beyond natural modifications with the invention of an increasing number of artificial modifications. This review delves into the common types of RNA modifications, including base, ribose, and phosphate modifications, discussing their impact on RNA structure and how these modifications influence the biological characteristics of RNA. The current applications of these modifications in the biotechnology field are summarized, highlighting their significance in RNA-based therapies.

Numerous preanalytical variables (sample collection, pretreatment and storage conditions, miRNA extraction, etc.) can influence miRNA detection. Understanding the various properties of miRNA, especially its stability in biofluids, is important in various types of miRNA studies, both fundamental and applied. This study aimed to evaluate the influence of plasma storage conditions and certain RNA extraction parameters on stability of endogenous miRNAs in human blood plasma. We report stability kinetics of four endogenous miRNAs (-16, -19b, -23a, -451a) and cel-miR-39 as exogenous miRNA under short and long-term incubation at different temperatures as well as the effect of long-term storage on extracellular vesicles miRNAs stability. The most stable of the endogenous ones was miRNA-23a. When studying archival samples (1–2 and 9–10 years of storage) of blood plasma from healthy donors, it was shown, that the concentrations of all endogenous miRNAs are steadily decreasing. These findings further show that endogenous miRNA levels do not remain stable during prolonged storage at −20°C. Although packaging of miRNA in extracellular vesicles stabilizes miRNA to some extent, it nevertheless the level decreases over a period of time from 6 months to 6 years. We have also evaluated the effect of the reagents used in the extraction process on miRNA recovery. The addition of guanidine isothiocyanate containing denaturation buffer alone prevented degradation of the synthetic cel-miR-39 miRNA spiked-in to blood plasma. In the presence of denaturation buffer with or without 2-mercaptoethanol the yields were higher than with just 2-mercaptoethanol or in the absence of any agents. Addition of the commercial RNA-stabilizing agent RNAlater did not result in significant retention of miRNA in plasma, but significantly worsened the efficiency of miRNA isolation. Thus, the degradation rate of miRNAs can be affected by their structure and packaging. Addition of various stabilization solutions to biofluids can affect the efficiency of miRNA extraction.

The polarization of macrophages towards an anti-inflammatory and/or pro-tissue repairing phenotype has shown promising potential in the treatment of ischemic diseases. Macrophages play a crucial role in promoting the growth of new blood vessels in ischemic tissue by clearing apoptotic debris caused by hypoxia, recruiting immune cells that support tissue repair, and releasing a variety of cytokines and growth factors. However, there is still a significant knowledge gap regarding the effective induction of this specific macrophage polarization. Non-coding RNAs have demonstrated promise in regulating macrophage activity, although there is a need for more efficient delivery system. Exosomes, which are cell-derived extracellular vesicles ranging from 30 nm to 200 nm in size, have emerged as promising carriers of non-coding RNAs for regulating macrophage activity. This review will discuss the important role of macrophage polarization in ischemic diseases and explore the potential of non-coding RNAs delivered by exosomes in modulating macrophage polarization.

Head and neck cancers (HNCs) are malignant tumors that differ from carcinomas in their biological behaviour and require a different diagnostic and treatment approach, especially in cancers like lung, breast, and prostate. Exosomal RNA (exRNA), particularly miRNA, mRNA, and lncRNA in blood or other body fluids through liquid biopsy, is emerging as a non-invasive biomarker for early cancer detection, prognosis, and treatment monitoring. Exosomal RNA modulates key signalling pathways like NF-κB, EGFR, PI3K/AKT/mTOR, and TP53 and contributes to the development, progression and therapeutic resistance of cancers. In this review, we focus on the roles of exosomal RNA in the growth and evolution of head and neck squamous cell carcinoma (HNSCC) as well as the emerging therapeutic strategies targeting exosomal RNA to improve clinical outcomes in HNC patients.

Gutter oil, a major public health concern in East Asia, is often indistinguishable from pure edible oils using conventional physical and chemical methods. In this study, we present a novel approach for detecting gutter oil using microRNAs (miRNAs) as biomarkers. We proved that miRNAs exist in edible oils and can be used to differentiate between pure and recycled oils. A combination of qRT-PCR and machine learning techniques was employed to characterize miRNA profiles across commercial vegetable oils, animal oils, and gutter oil. Specifically, the relative abundances of miR-16 and let-7a were found to be significantly different among these oils, allowing for accurate differentiation via a support vector machine (SVM) model. The results indicate that miRNAs such as miR-16 and let-7a serve as reliable biomarkers, enabling classification of gutter oil even when it complies with national standards. This research provides a feasible and effective method for detecting gutter oil, with potential implications for improving food safety and public health.

Mesenchymal stem cells (MSCs) are known for their ability to differentiate and self-renew, playing a critical role in tissue homeostasis and repair. Despite their therapeutic potential, clinical applications of MSCs face challenges, including safety concerns and uncertain effects on tumors. In contrast, MSC-derived exosomes (MSC-EXOs) have shown comparable or superior efficacy across various diseases, primarily due to their cargo of functional RNAs and proteins. These natural nanovesicles offer a promising drug delivery platform, combining the advantages of both MSCs and exosomes. Genetic engineering approaches, such as surface modification and drug loading, further enhance their therapeutic capabilities. Small RNA drugs present novel opportunities for expanding therapeutic targets, but efficient delivery remains a significant challenge. MSC-EXOs, either natural or engineered, provide a safe and effective solution for delivering small RNA drugs, holding great promise for both research and translational applications. However, large-scale production of MSC-EXOs remains a key hurdle, and ongoing efforts focus on optimizing strategies for producing high-quality MSC-EXOs in sufficient quantities for industrial and clinical use. This review examines the role of MSC-EXOs in small RNA drug delivery, highlighting the associated challenges and potential solutions for scalable production.