Abstract: Objective To investigate the activation of autophagy induced by IFN-γ in fPMSCs cultured in serum-free medium, so as to determine the role of autophagy in the capacity of proliferation in MSCs. Methods Enzyme dissociation was used in the isolation of MSCs of fetal side from human placenta. The characteristic of MSCs were identified by flow cytometry analysis and differentiation culture system. After fPMSCs were treated with 50?g/L IFN-γ, the expression of autophagy marker gene LC3Ⅰ/Ⅱ was measured by western blot assay; fPMSCs were infected with mRFP-GFP-LC3 adenovirus, the puncta light was observed by confocal fluorescence microscopy; MTT assay was employed to identify the effect of autophagy induced by IFN-γ in fPMSCs for the capacity of proliferation. The normal cells and the cells treated with 3-Ma was as control sets in the same way. Results The cells isolated from human placenta of fetal side expressed MSCs surface marker CD73, CD90 and CD105, but did not express CD14, CD34 and CD45, and had the ability of differentiation into adipogenic and osteogenic cells. IFN-γ could increase the transfer ratio of LC3Ⅰ to LC3 II (P <0.05), and induce more puncta light existed in cytoplasm by Confocal fluorescence microscope. 3-Ma could alleviate the inhibition of proliferation carried by IFN-γ in fPMSCs (P <0.05). Conlusion The autophagy induced by IFN-γ negatively regulated the ability of proliferation in fPMSCs.

Key words: human placenta, mesenchymal stem cells, interferon, autophagy, proliferation