Endogenous RNAs Modulate MicroRNA Sorting to Exosomes and Transfer to Acceptor Cells
Mario Leonardo Squadrito,
Caroline Baer,
Frédéric Burdet,
Claudio Maderna,
Gregor D. Gilfillan,
Robert Lyle,
Mark Ibberson,
Michele De Palma
Affiliations
Mario Leonardo Squadrito
Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
Caroline Baer
Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
Frédéric Burdet
Vital-IT, Swiss Institute of Bioinformatics (SIB), 1015 Lausanne, Switzerland
Claudio Maderna
Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
Gregor D. Gilfillan
Department of Medical Genetics and Norwegian High-Throughput Sequencing Centre (NSC), Oslo University Hospital, Kirkeveien 166, 0407 Oslo, Norway
Robert Lyle
Department of Medical Genetics and Norwegian High-Throughput Sequencing Centre (NSC), Oslo University Hospital, Kirkeveien 166, 0407 Oslo, Norway
Mark Ibberson
Vital-IT, Swiss Institute of Bioinformatics (SIB), 1015 Lausanne, Switzerland
Michele De Palma
Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
MicroRNA (miRNA) transfer via exosomes may mediate cell-to-cell communication. Interestingly, specific miRNAs are enriched in exosomes in a cell-type-dependent fashion. However, the mechanisms whereby miRNAs are sorted to exosomes and the significance of miRNA transfer to acceptor cells are unclear. We used macrophages and endothelial cells (ECs) as a model of heterotypic cell communication in order to investigate both processes. RNA profiling of macrophages and their exosomes shows that miRNA sorting to exosomes is modulated by cell-activation-dependent changes of miRNA target levels in the producer cells. Genetically perturbing the expression of individual miRNAs or their targeted transcripts promotes bidirectional miRNA relocation from the cell cytoplasm/P bodies (sites of miRNA activity) to multivesicular bodies (sites of exosome biogenesis) and controls miRNA sorting to exosomes. Furthermore, the use of Dicer-deficient cells and reporter lentiviral vectors (LVs) for miRNA activity shows that exosomal miRNAs are transferred from macrophages to ECs to detectably repress targeted sequences.
