Cell-derived nanovesicles from mesenchymal stem cells as extracellular vesicle-mimetics in wound healing

Wound healing is a dynamic process that involves a series of molecular and cellular events aimed at replacing devitalized and missing cellular components and/or tissue layers.Recently,extracellular vesicles(EVs),naturally cell-secreted lipid membrane-bound vesicles laden with biological cargos including proteins,lipids,and nucleic acids,have drawn wide attention due to their ability to promote wound healing and tissue regeneration.However,current exploitation of EVs as therapeutic agents is limited by their low isolation yields and tedious isolation processes.To circumvent these challenges,bioinspired cell-derived nanovesicles(CDNs)that mimic EVs were obtained by shearing mesenchymal stem cells(MSCs)through membranes with different pore sizes.Physical characterisations and highthroughput proteomics confirmed that MSC-CDNs mimicked MSC-EVs.Moreover,these MSC-CDNs were efficiently uptaken by human dermal fibroblasts and demonstrated a dose-dependent activation of MAPK signalling pathway,resulting in enhancement of cell proliferation,cell migration,secretion of growth factors and extracellular matrix proteins,which all promoted tissue regeneration.Of note,MSC-CDNs enhanced angiogenesis in human dermal microvascular endothelial cells in a 3D PEGfibrin scaffold and animal model,accelerating wound healing in vitro and in vivo.These findings suggest that MSC-CDNs could replace both whole cells and EVs in promoting wound healing and tissue regeneration.

Nano-confined superfluid-based highly efficient chemical reaction and signal transmission

Biological systems are featured by ultralow energyconsumption and ultrahigh efficiency in terms of biosynthesis,energy conversion,and signal transmission(e.g.,signal propagation along the neuronal axon).

The road less traveled:A new phosphorothioate antiviral defense mechanism discovered in Archaea

The story of phosphorothioate modifications of DNA begins over 50 years ago and has unfolded like Frost's walk in the woods[1].In 1970,Fritz Eckstein synthesized oligonucleotides in which a non-bridging oxygen in the phosphodiester backbone was replaced by sulfur–the first phosphorothioate-modified nucleic acid[2].Twenty years passed until Zixin Deng and colleagues discovered a DNA degradation phenotype in bacteria possessing a 5-gene dnd cluster,with electrophoretic degradation caused by incorporation of sulfur into bacterial genomes[3].These roads of chemistry and biology met again another 20 years later with the discovery by Wang et al.that Dnd proteins insert sulfur as a phosphorothioate in the genomes of diverse bacteria[4].This walk in the woods now picked up speed.