Molecular patterns of RNA pathogens and immune response to exogenous RNA: recognition mechanisms and therapeutic potential

Introduction. Innate immunity represents the first line of defense against pathogens, based on recognition of conserved molecular patterns (PAMPs) through specialized pattern recognition receptors (PRRs). RNA-containing viral patterns are of particular importance, including double-stranded RNA, single-stranded RNA with specific structural motifs, and RNA with 5’-triphosphate groups. Recognition of these molecular structures triggers signaling cascades leading to production of interferons and proinflammatory cytokines. Objective: to systematize current data on molecular mechanisms of RNA pattern recognition by innate immunity, analyze signaling pathways of interferon response activation, and evaluate therapeutic potential of modulating these pathways. Material and methods. A systematic analysis of scientific literature in PubMed, Scopus, Web of Science databases for 2010-2025 was conducted using key terms: pattern recognition receptors, RNA PAMPs, TLR3, RIG-I, MDA5, interferon response, RNA vaccines. Results. Main classes of RNA-recognizing receptors were identified: endosomal Toll-like receptors (TLR3, TLR7/8) and cytosolic RIG-I-like receptors (RIG-I, MDA5). Recognition specificity was established: RIG-I is activated by short double-stranded RNA (< 500 nucleotides) with 5’-triphosphate group, while MDA5 is specific to long dsRNA (> 500 base pairs). Receptor activation triggers signaling cascades through adapter proteins MAVS and TRIF, leading to phosphorylation of transcription factors IRF3/IRF7 and NF-kB, with subsequent induction of interferon genes and proinflammatory cytokines. Conclusion. Understanding molecular mechanisms of RNA pattern recognition opens new possibilities for developing immunotherapeutic strategies. Modulation of pattern recognition receptor activation allows either enhancing antiviral and antitumor immunity (using agonists) or reducing unwanted innate immune activation (using modified RNA in vaccines and gene therapy).