MicroRNAs (miRNAs) are small non-coding RNA molecules that play a key role in regulating gene expression. They are typically 18-23 nucleotides in length and can bind to the 3' untranslated region of target messenger RNAs, leading to either degradation of the mRNA or inhibition of translation. MiRNAs are involved in a wide range of biological processes, including development, differentiation, apoptosis, and metabolism. Dysregulation of miRNAs has been implicated in various diseases, including cancer, cardiovascular disorders, and neurological conditions. Research in the field of miRNAs has focused on identifying miRNA targets, elucidating their functional roles in different cell types and tissues, and developing therapeutic strategies targeting miRNAs for disease treatment. Overall, miRNAs represent an important and rapidly evolving area of research in molecular biology and medicine.