Evaluation of CD49f as a novel surface marker to identify functional adipose‐derived mesenchymal stem cell subset

OBJECTIVES: CD49f is expressed on a variety of stem cells and has certain effects on their cytological functions, such as proliferation and differentiation potential. However, whether CD49f is expressed on the surface of adipose tissue‐derived mesenchymal stem cells (ADSCs) and its effect on ADSCs has not been clarified. MATERIALS AND METHODS: The effects of in vitro culture passage and inflammatory factor treatment on CD49f expression and the adhesion ability of ADSCs from mice and rats were investigated. CD49f(+) cells were selected from rat ADSCs (rADSCs) by magnetic‐activated cell sorting (MACS), and the cellular functions of CD49f(+) ADSCs and unsorted ADSCs, including their clonogenic, proliferation, adipogenic and osteogenic differentiation, migration and anti‐apoptotic capacities, were compared. RESULTS: CD49f expression and the adhesion ability of ADSCs decreased with increasing in vitro culture passage number. TNF‐α and IFN‐γ treatment decreased CD49f expression but increased the adhesion ability of ADSCs. After CD49f was blocked with an anti‐CD49f antibody, the adhesion ability of ADSCs was decreased. No significant difference in clonogenic activity was observed between unsorted ADSCs and CD49f(+) ADSCs. CD49f(+) ADSCs had greater proliferation, adipogenic and osteogenic differentiation, migration and anti‐apoptotic capacities than unsorted ADSCs. CONCLUSION: In the current study, the expression of CD49f on ADSCs was identified for the first time. The expression of CD49f on ADSCs was influenced by in vitro culture passage number and inflammatory factor treatment. Compared with unsorted ADSCs, CD49f (+) ADSCs exhibited superior cellular functions, thus may have great application value in mesenchymal stem cell (MSC)‐based therapies.