Exosome-Based Gene Therapy for MicroRNA Delivery

Despite recent advances in scientific knowledge and clinical practice, cardiovascular disease management and treatment remain a major burden. While several treatment strategies using drugs and surgeries are being developed for cardiovascular manifestations, gene-based therapies hold significant promise. Recent findings by researchers at the Icahn School of Medicine unveiled a novel mechanism that exosomes, secreted nanovesicles from stem cells, mediate cardiac repair via transferring their unique repertoire of microRNAs (miRNA) to recipient cells in the heart. Exosomes, unlike other vectors for gene delivery, present unique advantages such that exosomes are a cell-free natural system for ferrying RNA between cells, robust exosomal membrane can protect the RNA/gene of interest from digestion, and exosomes are rapidly taken up by target cells making them a more efficient vehicle for gene delivery.

Here, the researchers describe a stepwise protocol developed in our laboratory for generating exosomes from human CD34+ stem cells that carry exogenously applied Cy3 dye-labeled pre-miR miRNA precursors. They demonstrate that human CD34+ stem cell exosomes can rigorously enter into recipient cells and deliver Cy3 dye-labeled pre-miR miRNA precursors to regulate gene expression. Identification of key molecular targets to treat disease conditions is the foremost critical step and the novel approach presented here to generate exosomes carrying exogenous genetic information offers a valuable clinical tool for more effective treatment strategies.

In vitro monitoring of human CD34⁺ stem cell derived exosomes-mediated delivery of Cy3 dye-labeled pre-miR m iRNA precursors in GFP-tagged HUVECs. Visualization of human CD34⁺ stem cell-derived exosomes inside HUVECs. Red color is representative of Cy3 miRNA containing exosomes after entering HUVEC cells. HUVEC cells expressing green fluorescent protein