Gallic Acid Derivative Stimulate Osteogenic Differentiation by Regulating Autophagy via JNK/mTOR Signaling Pathways in vitro

This paper was to demonstrate the effects and mechanism of methylated-based gallates 4-O-methylgallic acid on osteoblast differentiation. Cells were treated with different concentrations of 4-O-methylgallic acid.Then researchers evaluated the overall effects of 4-O-methylgallic acid on osteoblast by cell proliferation bioassay, ALP activity assay, Alizarin red S staining and detection the expression level of osteogenic-related gene including runt-related transcription factor 2 (RUNX2), bone sialoprotein (BSP), osteocalcin (OCN), alpha-1 type I collagen (COL1A1).Subsequently, cells were treated with ZXHA-TC with or without the JNK inhibitor SP600125 and the autophagy inhibitor 3-methyladenine (3-MA).Then western blotting and cell transfection were used by two researchers explore the potential relationship and signaling pathway between autophagy and the differentiation of osteoblast mediated by 4-O-methylgallic acid.The results of the present study demonstrated that 4-O-methylgallic acid stimulated cell viability, increased ALP activity, upregulated the expression of osteogenic genes, evoked the expression of autophagy markers. A range of 6.25x10-3μg/ml to 6.25x10-1μg/ml were recommended, within which 6.25x10-2μg/ml showed the best performance. SP600125 and 3-methyladenine suppressed the stimulating effects of 4-O-methylgallic acid on osteogenic differentiation By blocking JNK/mTOR signaling pathway.This study indicated that 4-O-methyl gallic acid stimulated osteoblast differentiation by regulating autophagy via JNK/mTOR signaling pathways.