Abstract
The present study aimed to evaluate the effect of tissue inhibitor of metalloproteinase-1 (TIMP-1) on the proliferation and osteogenic differentiation potential of human bone marrow-derived MSCs (hBMSCs). hBMSCs with stable TIMP-1 overexpression or TIMP-1 knockdown were generated. Osteogenic differentiation was assessed by Alizarin Red S staining, alkaline phosphatase (ALP) activity and expression of specific markers. Compared with the vehicle controls, TIMP-1 knockdown significantly promoted the growth of hBMSCs. TIMP-1 knockdown up-regulated β-catenin and cyclin D1 proteins. During osteogenic differentiation, TIMP-1 knockdown elevated the deposition of calcium nodules, ALP activity and the mRNA levels of the osteogenic markers sex determining region Y-box 9 (Sox9), CCAAT-enhancer-binding protein and peroxisome proliferator-activated receptor γ. During osteogenic differentiation, TIMP-1 knockdown significantly enhanced the up-regulation of osteocalcin proteins. Meanwhile, TIMP-1 overexpression attenuated the Wnt/activator Wnt3a-induced up-regulation cyclin D1 and Runt-related transcription factor 2 (RUNX-2) (during osteogenic differentiation) proteins, while TIMP-1 knockdown restored the inhibitor Dickkopf 1-induced inhibition effect on the expression of β-catenin, cyclin D1 and RUNX-2. TIMP-1 plays a negative regulatory role in the proliferation and osteogenesis of hBMSCs, at least partially, through Wnt/β-catenin signaling.