MicroRNA sequence codes for small extracellular vesicle release and cellular retention

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Small extracellular vesicles (sEVs), including exosomes, mediate intercellular communication via microRNAs (miRNAs).
• Mechanisms governing miRNA sorting into sEVs or cellular retention are largely unknown.

Purpose of the Study:

• To elucidate the sorting mechanisms of miRNAs into sEVs or for cellular retention.
• To identify sequence-specific sorting signals within miRNAs.
• To explore the implications for cell-specific miRNA profiles and therapeutic applications.

Main Methods:

• Identification and characterization of miRNA sorting sequences (EXOmotifs and CELLmotifs).
• Experimental manipulation of these motifs to alter miRNA secretion and retention.
• Investigation of RNA-binding proteins involved in miRNA export.

Main Results:

• miRNAs contain specific sorting sequences (EXOmotifs for secretion, CELLmotifs for retention).
• Different cell types exhibit preferential use of specific motifs, defining their sEV miRNA profiles.
• RNA-binding proteins Alyref and Fus are implicated in the export of specific EXOmotifs.
• Modulating EXOmotifs enhances miRNA delivery and target gene inhibition in recipient cells.

Conclusions:

• A miRNA sorting code determines secretion or retention, influencing the sEV miRNA profile of cell types.
• This code provides insights into linking circulating miRNAs to tissue origins.
• The findings offer a strategy for enhancing targeted RNA-mediated therapies.