(M-499) Enrichment of Angiogenic and Myogenic Factors in Stem Cell-Derived Exosomes to promote Vascularization and Muscle Regeneration in Ischemic Hindlimbs

Introduction:: Exosomes have emerged as a potential therapeutic candidate for tissue regeneration, offering advantages such as reduced immune rejection risk, easer of manipulation and storage, and less safety concerns compared to cell-based therapies. Therapeutic efficacy of the exosomes is dependent on their cargo composition. Upregulating cargos that promote tissue regeneration is expected to increase therapeutic efficacy. In this study, we investigated whether enhancing N-cadherin interaction of human-induced pluripotent stem cell-derived mesenchymal stem cells (iMSCs) can upregulate the expressions of angiogenic and myogenic factors in the exosomes, thus promoting vascularization and muscle regeneration in ischemic hindlimbs.


Materials and Methods:: iMSCs were seeded on N-cadherin mimicking peptide HAVDIGGGK-functionalized glass dishes, and the exosomes (H-EXO) were collected after incubating the cells under hypoxia (1% O₂) for 3 days. The exosomes collected from iMSCs cultured on glycine-functionalized glass dishes were used as control (G-EXO). To prolong the circulation time of the exosomes and facilitate their specific accumulation in ischemic skeletal muscles following IV injection, we cloaked the exosomes with platelet membranes followed by conjugating with an ischemia-homing peptide. The engineered exosomes were then injected intravenously into diabetic mice after induction of ischemia in the hindlimbs.


Results, Conclusions, and Discussions:: Enhancing N-cadherin interaction increased expressions of multiple angiogenic and myogenic factors in the iMSC-derived exosomes (H-EXO), such as VEGF, bFGF, PDGF-BB, HGF, miR-126-3p, miR-296-3p, miR-21-5p, and miR-182-5p. In vitro studies showed that the H-EXO significantly increased survival, migration, and morphogenesis of endothelial cells and myoblasts under hypoxia, by activating AKT and ERK1/2 signaling pathways. In a murine ischemic hindlimb model, the group injected with H-EXO significantly promoted vascularization and muscle regeneration compared to the groups injected with controls, G-EXO or PBS (Figure 1).
In summary, our study shows that enhancing N-cadherin interaction of iMSCs significantly upregulated expressions of angiogenic and myogenic factors in the exosomes. Intravenous application of these exosomes promoted vascularization and muscle regeneration in the ischemic hindlimbs.


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