Zinc finger protein 521 suppresses osteogenic differentiation of rat mesenchymal stem cells by inhibiting the Wnt/beta-catenin signaling pathway

Zinc finger protein 521 (Zfp521) is involved in a number of cellular processes in a variety of cells and tissues. In the present study, the effects of Zfp521 on osteogenic differentiation of rat mesenchymal stem cells (MSCs) were investigated. The results showed that, in rat MSCs, knocking down cellular Zfp521 by short hairpin RNA (shRNA) decreases cell proliferation while promoting ALP activity, calcium accumulation, and the expression of mRNA that encodes bone sialoprotein (BSP), osteocalcin (OCN) and Runx2. Furthermore, in Zfp521-depleted cells, the up-regulation of phospho-Wnt (p-Wnt) and beta-catenin expression levels was detected. However, over-expression of Zfp521 played the opposite role in proliferation and osteogenic differentiation of rat MSCs. To further demonstrate the functions of the Wnt/beta-catenin signaling in Zfp521 regulated-osteogenic differentiation, the activation of Wnt/beta-catenin was blocked with IWP-2 inhibitor. The suppression of the Wnt/beta-catenin pathway completely abrogated the effects of Zfp521 knockdown on osteogenic differentiation of rat MSCs. Therefore, we conclude that Zfp521 regulates osteogenic differentiation of rat MSCs through the suppression of the Wnt/beta-catenin signaling pathway.