Boosting the biogenesis and secretion of mesenchymal stem cell-derived exosomes

A limitation to using exosomes to their fullest potential is their limited secretion from cells, a major bottleneck to efficient exosome production and application. This is especially true for mesenchymal stem cell (MSCs), which can self-renew but have limited expansion capacity, undergoing senescence after only a few passages, with exosomes derived from senescent stem cells showing impaired regenerative capacity compared to young cells. Here we examined the effects of small molecule modulators capable of enhancing exosome secretion from MSCs. Treatment of MSCs with a combination of methyldopamine and norepinephrine robustly increased exosome production by three-fold without altering the ability of the MSC exosomes to induce angiogenesis, polarize macrophages to the anti-inflammatory phenotype, or inhibit fibrosis. These small molecule modulators provide a promising means to increase exosome production by MSCs.