Epigenetics in clinical transplantology: diagnostic, predictive, and therapeutic significance of microRNA molecules (systematic review)

Epigenetics is the study of changes in gene expression that occur without alterations in the primary DNA sequence. These changes are mediated by chemical modifications of DNA, histones, and non-coding RNAs, collectively forming the epigenome, that determines the functional activity of the genome. Epigenetic mechanisms play a fundamental role in cellular differentiation, organismal development, and adaptation to external conditions. In medicine, they have attracted considerable attention due to their involvement in the pathogenesis of oncological, autoimmune, and neurodegenerative diseases. MicroRNAs (miRNAs), as key components of epigenetic mechanisms, play a critical role in controlling immune responses, including those occurring after organ transplantation. This has opened new opportunities for a personalized approach to the management of transplant recipients. Accumulating evidence on the role of miRNAs in solid organ transplantation suggests that integration of omics technologies may expand the existing arsenal of diagnostic criteria, serving as an auxiliary diagnostic tool for monitoring graft function. This systematic review presents a comprehensive analysis of the current literature on the clinical significance of miRNAs in modern transplantology. It highlights the diagnostic and predictive potential of specific miRNAs in relation to the development of complications in recipients of heart, lung, kidney, and liver transplants, and examines current approaches to the use of miRNAs as therapeutic targets.