Tissue Inhibitor of Metalloprotease-1 (TIMP-1) Regulates Adipogenesis of Adipose-derived Stem Cells (ascs) Via the Wnt Signaling Pathway in an MMP-independent Manner

Tissue inhibitor of metalloprotease-1 (TIMP-1) is a tissue inhibitor of matrix metalloproteinases (MMPs).It however exerts multiple effects on biological processes,such as cell growth,proliferation,differentiation and apoptosis,in an MMP-independent manner.This study aimed to examine the role of TIMP-1 in adipogenesis of adipose-derived stem cells (ASCs) and the underlying mechanism.We knocked down the TIMP-1 gene in ASCs through lentiviral vectors encoding TIMP-1 small interfering RNA (siRNA),and then found that the knockdown of TIMP-1 in ASCs promoted the adipogenic differentiation of stem cells and inhibited the Wnt/β-catenin signaling pathway in ASCs.We also noted that mutant TIMP-1 without the inhibitory activity on MMPs promoted the activation of Wnt/β-catenin pathway as well as the recombinant wild type TIMP-1 did,which indicated that the effect of TIMP-1 on Wnt/β-catenin pathway was MMP-independent.Our study suggested that TIMP-1 negatively regulated the adipogenesis of ASCs via the Wnt/β-catenin signaling pathway in an MMP-independent manner.