Circulating miRNAs can be found in extracellular vesicles (EV) and could be involved
in intercellular communication. Here, we report the biodistribution of EV associated
miR-155 using miR-155 KO mouse model. Administration of exosomes loaded with synthetic
miR-155 mimic into miR-155 KO mice resulted in a rapid accumulation and clearance
of miR-155 in the plasma with subsequent distribution in the liver, adipose tissue,
lung, muscle and kidney (highest to lowest, respectively). miR-155 expression was
detected in isolated hepatocytes and liver mononuclear cells of recipient KO mice
suggesting its cellular uptake. In vitro, exosome-mediated restoration of miR-155
in Kupffer cells from miR-155 deficient mice augmented their LPS-induced MCP1 mRNA
increase. The systemic delivery of wild type plasma to miR-155 KO mice also resulted
in a rapid accumulation of miR-155 in the circulation and distribution to the liver
and adipose tissue. In summary, our results demonstrate tissue biodistribution and
biologic function of EV-associated miR-155.
