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A limitation of 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 cells (MSCs), which can self-renew but have a 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. The treatment of MSCs with a combination of N-methyldopamine and norepinephrine robustly increased exosome production by three-fold without altering the ability of the MSC exosomes to induce angiogenesis, polarize macrophages to an anti-inflammatory phenotype, or downregulate collagen expression. These small molecule modulators provide a promising means to increase exosome production by MSCs.
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In‐Drop Thermal Cycling of Microcrystal Assembly for Senescence Control with Minimal Variation in Efficacy
Abstract The secretome from mesenchymal stem cells (MSCs) have recently gained attention for new therapeutics. However, clinical application requires in vitro cell manufacturing to attain enough cells. Unfortunately, this process often drives MSCs into a senescent state that drastically changes cellular secretion activities. Antioxidants are used to reverse and prevent the propagation of senescence; however, their activity is short‐lived. Polymer‐stabilized crystallization of antioxidants has been shown to improve bioactivity, but the broad crystal size distribution (CSD) significantly increases the efficacy variation. Efforts are made to crystalize drugs in microdroplets to narrow the CSD, but the fraction of drops containing at least one crystal can be as low as 20%. To this end, this study demonstrates that in‐drop thermal cycling of hyaluronic acid‐modified antioxidant crystals, named microcrystal assembly for senescence control (MASC), can drive the fraction of microdrops containing crystals to >86% while achieving significantly narrower CSDs (13 ± 3 µm) than in bulk (35 ± 11 µm). Therefore, this approach considerably improves the practicality of CSD‐control in drops. In addition to exhibiting uniform release, MASC made with antioxidizing N‐acetylcysteine extends the release time by 40%. MASC further improves the restoration of reactive oxygen species homeostasis in MSCs, thus minimizing cellular senescence and preserving desired secretion activities. It is proposed that MASC is broadly useful to controlling senescence of a wide array of therapeutic cells during biomanufacturing.
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- Award ID(s):
- 1735252
- PAR ID:
- 10410782
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 33
- Issue:
- 37
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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