In recent years, the realm of non-coding RNA (ncRNA) research has witnessed a paradigm shift, thanks to the emergence of sophisticated computational tools. These in silico methodologies have transformed the landscape of ncRNA target prediction, allowing researchers to delve deeper into the intricate mechanisms of gene regulation. By leveraging computational resources, scientists can now identify potential ncRNA candidates and their target genes with remarkable precision and efficiency.

Overall taxonomy of ncRNA. Amin, N., McGrath, A. & Chen, YP.P. Evaluation of deep learning in non-coding RNA classification. Nature Machine Intelligence 1, 246–256 (2019). https://doi.org/10.1038/s42256-019-0051-2.
Types of non-coding RNA molecule. There are types of ncRNAs categorized according to their functional role in the biological aspect; housekeeping and regulatory ncRNAs. The housekeeping ncRNAs include ribosomal RNA (rRNA), transfer RNA (tRNA), small nuclear RNA (snRNA), and small nucleolar RNA (snoRNA). Regulatory ncRNAs are microRNA (miRNA), small interfering RNA (siRNA), piwi RNA (piRNA), and small Cajal body-specific RNA (scaRNA), long intergenic ncRNAs (lincRNA), circular RNA (circRNA). Morris, K. V, Chan, S. W.-L., Jacobsen, S. E. & Looney, D. J. Small Interfering RNA-Induced Transcriptional Gene Silencing in Human Cells. Science (1979) 305, 1289–1292 (2004).Retrieved from https://www.biorender.com/template/types-of-non-coding-rna-molecule.

The accessibility of various computational tools and databases plays a crucial role in this endeavor. Designed with user-friendliness in mind, these web-based platforms empower researchers without requiring extensive programming skills. This democratization of technology has broadened the scope of ncRNA research, enabling more scientists to participate in the discovery process. However, it is important to note that the predictive power of a single computational tool may be limited. Combining multiple approaches can significantly enhance the accuracy of identifying experimentally verifiable ncRNA-target interactions.

The landscape of ncRNA target prediction is rich with publicly available tools and databases. Among the most notable is miRBase, a comprehensive repository of miRNA sequences and annotations. With its vast collection of precursor and mature miRNA entries, miRBase provides an invaluable resource for researchers looking to explore miRNA interactions. These small RNA molecules repress gene expression by binding to miRNA response elements (MREs) on target RNAs, guided by the crucial seed region within the miRNA sequence.

Diagram of microRNA (miRNA) action with mRNA. Pre-miRNA instead of Pri-miRNA in the first point of mechanism. Filipowicz, W., Bhattacharyya, S. & Sonenberg, N. Mechanisms of post-transcriptional regulation by microRNAs: are the answers in sight?. Nat Rev Genet 9, 102–114 (2008). https://doi.org/10.1038/nrg2290 & Filipowicz, W., Bhattacharyya, S. & Sonenberg, N. Mechanisms of post-transcriptional regulation by microRNAs: are the answers in sight?. Nat Rev Genet 9, 102–114 (2008). https://doi.org/10.1038/nrg2290 & Ando Y, Maida Y, Morinaga A, Burroughs AM, Kimura R, Chiba J, Suzuki H, Masutomi K, Hayashizaki Y. Two-step cleavage of hairpin RNA with 5′ overhangs by human DICER. BMC Mol Biol. 2011 Feb 9;12:6. doi: 10.1186/1471-2199-12-6. PMID: 21306637; PMCID: PMC3048551.

Tools like DIANA-LncBase further extend the scope of ncRNA research by focusing on miRNA interactions with long non-coding RNAs (lncRNAs). This database curates a wealth of experimentally supported miRNA-lncRNA interactions, offering a robust platform for researchers investigating the regulatory roles of miRNAs beyond mRNAs.

Mechanisms for long noncoding RNA (lncRNA) function. (A) LncRNAs (in red) are able to recruit chromatin modifiers mediating the deposition of activatory (green dots) or repressive (red dots) histone marks. (B) LncRNAs control the recruitment of transcription factors and core components of the transcriptional machinery. (C) LncRNAs can directly bind mRNAs and modulate splicing events. (D-E) LncRNAs participate in the higher-order organization of the nucleus by mediating chromatin looping (D) and as structural components for the formation and function of nuclear bodies (E). (F) LncRNAs control translation rates favoring or inhibiting polysome loading to mRNAs. (G) LncRNAs modulate mRNA decay protecting mRNA from degradation or, alternatively, mediating the recruitment of degradation machinery. (H) LncRNAs can act as miRNA sponges, thus favoring the expression of the mRNAs targeted by the sequestered miRNA. Nuguembor, M.V., Jothi, M. & Gabellini, D. (2014). Long noncoding RNAs, emerging players in muscle differentiation and disease. Skeletal Muscle 4(1):8; doi: https://doi.org/10.1186/2044-5040-4-8.

To navigate the diverse landscape of miRNA target prediction, researchers must consider several factors. False positives are a common challenge, as different algorithms may yield divergent results based on varying stringencies and predictive parameters. Tools like miRWalk address this issue by integrating predictions from multiple sources, enhancing the reliability of the identified interactions. This combinatorial approach is pivotal in improving the predictive confidence of ncRNA-target interactions.

Understanding the biochemical features that underpin ncRNA-target interactions is essential for accurate predictions. The stability and efficiency of these interactions are often dictated by binding affinity and site accessibility. mRNAs, with their complex secondary structures, present both challenges and opportunities for ncRNA binding. Regions such as the 3′-untranslated regions (3′-UTRs) are typically more accessible and thus preferentially targeted by miRNAs.

Different 3′UTR-mediated regulatory mechanisms in bacteria. (A) Long 3′UTRs and transcriptional read-through can produce overlapping 3′UTRs that modulate the expression of convergent genes. These overlapping double-stranded RNA regions are processed by RNase III, which ultimately decreases protein expression. (B) 3′UTRs can interact with the 5′UTR of the same mRNA to modulate mRNA stability and translation. This interaction can inhibit translation and recruit RNases for mRNA degradation, or it can promote mRNA stability by impairing RNase processing. (C) RNases can specifically target 3′UTRs to process mRNAs and modify their half-life and protein expression yield. (D) sRNAs and RBPs can target 3′UTRs to modulate mRNA expression. This interaction can be both positive, by blocking RNase processing and enhancing mRNA stability, or negative by promoting inhibition of translation and RNase processing. (E) 3′UTRs are also reservoirs of trans-acting sRNAs than can be generated by an internal promoter within or immediately downstream of the CDS (type I) or by mRNA processing (type II). Menendez-Gil, P. & Toledo-Arana, A. (2021). Bacterial 3′UTRs: A Useful Resource in Post-transcriptional Regulation. Frontiers in Molecular Biosciences, 7, 617633. https://doi.org/10.3389/fmolb.2020.617633.

The minimum free energy (MFE) of hybridization between ncRNAs and their targets serves as a key indicator of binding affinity. Lower MFE values suggest stronger, more likely interactions. Tools like RNAhybrid and miRWalk enable researchers to calculate these energies, providing a quantitative basis for predicting ncRNA-mRNA interactions. For instance, RNAhybrid allows users to input sequences and adjust parameters to identify high-affinity binding sites, thereby refining the list of potential interactions for experimental validation.

miRWalk (http://mirwalk.uni-hd.de/), a comprehensive database that provides predicted as well as validated miRNA binding site information on miRNAs for human, mouse, and rat. miRWalk gathers all the information on predicted as well as validated miRNA targets, this database has the potential of becoming an important resource for scientists engaged with miRNA research.Dweep, H., Sticht, C. Pandey, P. & Gretz, N. (2011). miRWalk – Database: Prediction of possible miRNA binding sites by “walking” the genes of three genomes. Journal of Biomedical Informatics, 44(5): 839-847; doi: https://doi.org/10.1016/j.jbi.2011.05.002.

For larger RNA molecules, the ViennaRNA web services offer a suite of tools to analyze the structural and thermodynamic properties of RNA-RNA interactions. RNAfold and RNAcofold are particularly useful for predicting the secondary structures and binding affinities of lncRNAs and their targets. These tools not only enhance the understanding of ncRNA interactions but also facilitate the generation of publication-ready visualizations, making them accessible to both novice and experienced researchers.

Community-science-designed RNA datasets from the Eterna ‘Cloud Lab’ experiments identify consistent discrepancies in ensemble calculations from secondary structure packages. Wayment-Steele, H.K., Kladwang, W., Strom, A.I. et al. RNA secondary structure packages evaluated and improved by high-throughput experiments. Nat Methods 19, 1234–1242 (2022). https://doi.org/10.1038/s41592-022-01605-0.

In silico analysis extends beyond prediction to encompass the correlation of ncRNA and mRNA expression profiles. High-throughput technologies, such as microarrays and next-generation sequencing, have generated vast amounts of expression data. By mining these datasets, researchers can uncover the regulatory relationships between ncRNAs and their target mRNAs.

The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) are two prominent repositories that provide extensive genomic data for such analyses. TCGA, for instance, offers paired miRNA and mRNA expression profiles from the same samples, enabling researchers to eliminate biases caused by inter-sample variation. This feature is particularly valuable in cancer research, where gene expression can vary widely between tumor and non-tumor tissues.

The Cancer Genome Atlas (TCGA). The Cancer Genome Atlas (TCGA) has helped establish the importance of cancer genomics, transformed our understanding of cancer, and even begun to change how the disease is treated in the clinic. The impact goes even further, reaching health and science technologies, computational biology, and other research fields. After 12 years, contributions from over 11,000 patients, and incredible effort from thousands of researchers, TCGA has produced a rich data set of immeasurable value. This data remains available to the public as a trusted reference that will be mined for many.

Similarly, GEO hosts a vast array of high-throughput genomic data across various species and experimental conditions. Researchers can leverage these resources to perform integrative analyses, revealing novel ncRNA-mRNA interaction networks and their roles in biological processes. Expression Atlas further enriches this landscape by providing comprehensive data on RNA and protein expression across different tissues and conditions, facilitating a deeper understanding of ncRNA functions.

Gene Expression Omnibus (GEO) in Action. Fu Y, Zhao D, Zhou Y, Lu J, Kang L, Jiang X, Xu R, Ding Z, Zou Y. Identification of Differential Expression Genes between Volume and Pressure Overloaded Hearts Based on Bioinformatics Analysis. Genes. 2022; 13(7):1276. https://doi.org/10.3390/genes13071276.

The advent of in silico tools has revolutionized the field of ncRNA research, providing unprecedented insights into the complex regulatory networks that govern gene expression. By integrating computational predictions with experimental validation, researchers can unlock the full potential of ncRNAs as key regulators in various biological processes. As the repository of computational tools and databases continues to grow, so too does the promise of ncRNA research, paving the way for new discoveries and therapeutic innovations.

Engr. Dex Marco Tiu Guibelondo, B.Sc. Pharm, R.Ph., B.Sc. CpE

Editor-in-Chief, PharmaFEATURES

Share this:

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Cookie settings