rno-mir-21: Rno-mir-21 is a microRNA that has been extensively studied in various biological contexts. It has been found to be enriched in fibroblasts and fibroblast-derived extracellular vesicles (EXOs) [PMC6406975]. Detection probes for rno-mir-21, along with other microRNAs, were purchased for experimental analysis [PMC4905434]. In certain experimental conditions, the expression of rno-mir-21 did not significantly change, while other microRNAs such as rno-miR-340-3p, rno-miR-675, and rno-miR-425 showed significant increases [PMC8810107]. In different studies involving various tissues and experimental models, the expression of rno-mir-21 was found to be upregulated [PMC3682887] or downregulated [PMC3682887] in response to different stimuli. Manipulation of rno-mir-21 expression using mimics or inhibitors resulted in corresponding changes in its expression levels [PMC4519855]. Rno-mir-21 has been implicated in the regulation of various target genes and proteins involved in different biological processes such as cardiac hypertrophy and pain development [PMC5979605] [PMC8914318]. It has also been shown to be involved in the modulation of signaling pathways such as PI3K/AKT/mTOR signaling pathway [PMC5908320]. Overall, these studies highlight the importance of rno-mir-21 as a regulatory molecule with diverse functions across different biological systems.