Targeted delivery and tracking of exosomes in stroke

Exosomes, which are the component of extracellular vesicles and are shown to carry important small RNAs, mRNAs, protein and bioactive lipid from parent cells, are found in most biological fluids. Exosomes have been used for therapeutic purposes to target stroke and other disorders. Investigators have shown the importance of mesenchymal stem cells (MSCs) derived exosomes in the repair of stroke lesions. We have recently shown the whole body bio-distribution of accumulation of IV administered neural stem cell-derived exosomes to the sites of stroke. However, exosomes from endothelial progenitor cells (EPCs) have not been tested in any stroke model nor has there been an evaluation of whether these exosomes target/home to areas of pathology. We have optimized the method of collection of exosomes using centrifugal filters. Targeted delivery of IV administered exosomes has been a great challenge. Modification of exosomal surface to carry different ligands or peptides have been tried to increase delivery to target tissues. However, the overall results are not encouraging. A targeted delivery system is lacking to deliver naïve (unmodified) exosomes to the site of interest. Pulsed ultrasound (PUS) is being used for therapeutic and experimental purposes. Low-intensity pulsed ultrasound (LIPUS) is approved for clinical use in musculoskeletal and physiotherapy clinics. There has not been any report showing the use of focused (F) LIPUS to deliver exosome to the site of interests in models of stroke. The long-term objectives of the proposed studies are to determine in vivo biodistribution of exosomes collected from EPCs and targeted delivery to the brain and stroke regions using FLIPUS. We hypothesize that EPCs derived exosomes will accumulate to stroke area following IV administration, and FLIPUS will enhance homing retention of these exosomes to areas of pathology by increasing the expression of chemokine, cytokines, and other factors including adhesion molecules. The hypothesis will be tested with the following specific aims: Specific Aim 1: Investigate the in vivo biodistribution of IV administered exosomes collected from EPCs in stroke areas with or without FLIPUS. Specific Aim 2: Investigate recovery from a stroke following LIPUS enhanced delivery of exosomes. (AHA Program: Transformational Project Award)