Protocatechuic Acid Enhances Osteogenesis, but Inhibits Adipogenesis in C3H10T1/2 and 3T3-L1 Cells

Abnormal activation of adipogenesis in mesenchymal stem cells (MSCs) and preadipocyte cells is associated with human metabolic disorders, such as osteoporosis and obesity. This study investigated the biological effects of protocatechuic acid (PCA) on the modulation of osteogenesis and adipogenesis in cultured cells. PCA stimulation of MSCs significantly increased intracellular mineralization during osteogenesis, but reduced lipid accumulation in both MSCs and 3T3-L1 preadipocyte cells during adipogenesis. Reverse transcription-polymerase chain reaction and immunoblotting analyses showed a dose-dependent upregulation of proosteogenic runt-related transcription factor 2 due to induction of b-catenin. PCA reduced the expression of proadipogenic transcription factor, peroxisome proliferator-activated receptor-c, and suppressed its promotor activity. These results suggest PCA exerts stimulatory effects on the osteogenesis of MSCs and inhibitory effects on the adipogenesis of MSCs and 3T3-L1 cells. PCA may contribute to maintain a coordinated metabolic balance between adipogenesis and osteogenesis, and thus may be useful for the prevention and alleviation of osteoporosis and obesity.