Featured Articles - June 15, 2021

Development of an optimized and scalable method for isolation of umbilical cord blood-derived small extracellular vesicles for future clinical use
Renato M. S. Cardos, et al., STEM CELLS Translational Medicine

The present work describes an optimized process for the isolation of small extracellular vesicles (sEVs) from umbilical cord blood mononuclear cells (UCB-MNC), that allows for large-scale manufacturing, Good Manufacturing Practices (GMP) compliance and is easier to standardize than previously-described methods. sEV isolated with the described protocol were characterized based on their morphology, surface markers and protein, lipid, as well as RNA content. They were found to be enriched in anti-inflammatory and regenerative molecules to promote angiogenesis and extracellular remodeling, and to accelerate skin regeneration in a mouse model of delayed wound healing. The multifactorial effects of UCB-MNC-sEV support a competitive advantage over products available in the market, which typically stimulate only one phase of the wound healing.

The miR-200 family is required for ectodermal organ development through the regulation of the epithelial stem cell niche
Mason Sweat, et al., STEM CELLS

Current microRNA (miR) inhibition methods cannot be used to study in vivo developmental stem cell processes. CRISPR-Cas genome editing cannot specifically knockout a miR within a cluster. Embryonic Stem (ES) cells have been profiled for miR expression; however, cell-based assays using oligonucleotides targeting miRs are not specific and are toxic. The authors developed a highly specific, effective miR inhibitor that can be used to knockdown miRs during embryonic development to determine their effect on stem cells, cell proliferation, and differentiation. The authors show that the miR-200 family acts to compartmentalize an ectodermal stem cell niche by regulating progenitor cell differentiation during development.