Abstract: Objective To study the role of miR-320-3p in adipocyte differentiation. Methods Marrow mesenchymal stem cells were isolated from mice and cultured then induced with adipogenic agents for 3 days. The transcription level of miR-320-3p was examined by qRT-PCR. Stromal ST2 cells were transfected with miR-320-3p, followed by adipogenic treatment. Oil-red O staining and qRT-PCR were employed to assess the differentiation of adipocytes induced by miR-320- 3p. Results The expression level of miR-320-3p increased in MSCs after adipogenic treatment (P < 0.01). Addition of miR-320-3p in ST2 cells promoted the formation of oil-red O positive adipocytes and up-regulated the expression levels of adipogenic transcription factors such as peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding protein-α (C/EBPα) and the marker gene adipocyte fatty acid binding protein 4 (FABP4)，compared to cells that transfected with miR-320-3p mimics (P < 0.05). Conclusion miR-320-3p promotes ST2 cells differentiation into adipocytes.

Key words: adipocytes, mesenchymal stem cells, cell differentiation, adipogenesis, microRNAs, miR-320-3p