The transcription factor E2F1 modulates the proliferation and differentiation of adipose mesenchymal stem cells and its underlyingmechanism

Abstract

Objective To investigate the effect of transcription factor E2F1 on the proliferation and differentiation of adipose mesenchymal stem cells (ADSCs) and its underlying mechanism. Methods The primary culture cells of ADSCs were isolated from WT or E2F1-/-mice (6-8 weeks) adipose tissues. After 3rd generation culture of ADSCs (P4), the cell morphologies were observed and the cell surface markers were identified by flow cytometry. The proliferation and differentiation were compared between the two groups by cell counting kit-8 (CCK-8) and Oil-Red O staining assay. The expression levels of peroxisome proliferator activated receptor γ (PPAR-γ), which is the key regulator for adipogenesis, were detected by Western blotting. Results Firstly, the obtained ADSCs could stably grew and passaged, and the cell morphology was not significantly different in the two groups. The cell surface markers CD29, CD44, CD90 expression were positive while CD31 expression was negative. The CCK-8 result showed that the cell proliferation ability of WT ADSCs was stronger than E2F1-/-ADSCs (1.85±0.03 vs. 1.32±0.20, t=16.641, P<0.05). The Oil-Red O staining assay showed that lipid droplets in WT ADSCs group were more than those of E2F1-/-ADSCs group (1 890±128 vs. 1 109±116, t=18.505, P<0.05). The PPAR-γ protein expression level was higher in WT ADSCs group than that of E2F1-/-ADSCs group (0.81±0.02 vs. 0.44±0.01, t=3.040, P<0.05). Conclusion Transcription factor E2F1 can enhance the proliferation and lipid differentiation of ADSCs by promoting the expression of PPAR-γ. Key words: Adipose-derived mesenchymal stem cells; E2F1; Cell proliferation; Adipogenic differentiation; Peroxisome proliferator activated receptor γ