This invention relates to stem cell microparticles and miRNA isolated from these microparticles, their use and production thereof, in particular neural stem cell microparticles and their use in therapy of a disease or condition involving unwanted or undesirable cell migration. The stem cell microparticle is typically an exosome or microvesicle and may be derived from a neural stem cell line. The neural stem cell line may be a conditionally- immortalised stem cell line such as CTX0E03 (deposited at the ECACC with Accession No. 04091601).
