Abstract: Provided are a composition for regulating stem cell function comprising the genus Lactobacillus bacteria-derived extracellular vesicles as an active ingredient, and a method for regulating a stem cell function using the same, wherein the genus Lactobacillus bacterial-derived extracellular vesicles have the effect of greatly improving the proliferation of stem cells, and the extracellular vesicles are naturally secreted from a symbiotic the genus Lactobacillus strain in human tonsillar tissue and are human-friendly and natural substances, and thus can be used in various research fields by promoting the proliferation of aged stem cells with minimal toxicity and side effects.

Abstract: The present invention relates to a method of screening highly efficiently stem cells using the protein marker GRP78, and more particularly, to a method of removing old stem cells with decreased expression of GRP78 and isolating only highly efficient stem cells. The use of the protein marker GRP78 according to the present invention makes it possible to isolate only highly efficient stem cells by removing old stem cells. Thus, the protein marker GRP78 may be used as an effective marker for controlling the quality of stem cell therapy products and evaluating the stability and effectiveness thereof, and is useful in the production of stem cell therapy products having excellent therapeutic efficacy.