Lithium chloride enhances cathepsin H expression and BMP-4 degradation in C3H10T1/2 cells.

The effect of canonical Wnt/β-catenin signaling on chondrogenic differentiation induced by transfection of BMP4 expressing plasmid was analyzed. Lithium chloride (LiCl) which mimics canonical Wnt/β-catenin signaling was added to cells transfected with BMP4 expressing plasmid. Although BMP4 mRNA expression was not affected by LiCl, LiCl decreased BMP4 protein accumulation. Gene expression analysis exhibited upregulation of cathepsin H by LiCl treatment. Gene silencing of cathepsin H enhanced BMP4 protein accumulation from BMP4 expressing cells. These results suggested that cathepsin H is regulated by Wnt/β-catenin signaling and plays an important role in the regulation of BMP4 biological activity.