The instant disclosure provides RNA-modulating agents that function to recruit one or more small regulatory RNA molecules (e.g., miRNA molecules, Y RNAs, and siRNAs) to a target mRNA thereby modulating (e.g., inhibiting) the translation of the target mRNA or destabilizing the mRNA. Also provided are miRNA inhibitors and diagnostic agents that have improved binding affinity for their target miRNAs. Methods for using the RNA-modulating agents, miRNA inhibitors and diagnostic agents are also provided.