Modificaciones Químicas del ARN Influyen en la Estabilidad del Ensamblaje Micelar y la Distribución Intracelular de Complejos de Policationes/ARN

RNA molecules play a crucial role in regulating genetic information within cells and have increasingly emerged as a promising class of therapeutic agents for a wide range of diseases. The delivery of RNA to intracellular targets remains a pivotal challenge in advancing RNA-based therapeutics. Current research on RNA delivery has primarily concentrated on the design of delivery carriers and chemical modification of RNA. However, the influence of RNA structural characteristics, particularly chemical modifications, on the assembly properties and intracellular fate of cationic carrier/RNA complexes has been relatively overlooked. Hence, we systematically investigated how chemical modification of RNA influenced the micellar assembly and delivery properties of polycation/RNA complexes, using a cationic polymer (TPE-PEG2K-8R, TP8R) as a model carrier. Nine chemical modifications of RNA significantly altered the assembly, cellular uptake efficiency, and subcellular distribution patterns of polycation/RNA complexes by modulating interfacial interactions. Crucially, using anti-miR-21 as a therapeutic model, we have demonstrated that hydrophobic modifications (e.g., Cy5) induced mitochondrial uptake of the cargo, thus rendering it therapeutically inactive, while hydrophilic and metabolically stable modifications (e.g., 2'-OMe, PS) were essential for cytosolic delivery. This study is expected to establish RNA interfacial chemistry as a critical design parameter for optimizing nucleic acid delivery systems. STATEMENT OF SIGNIFICANCE: While RNA chemical modifications are widely used to enhance stability, their impact on carrier/RNA assembly remains unexplored. This study reveals RNA chemical modifications as pivotal regulators of polycation/RNA complex assembly and intracellular fate. Key findings reveal that.