The TGF-β1-Induced Expression of Matrix Metalloproteinases in Mesenchymal Stromal Cells is Influenced by Type of Substrate

Abstract

Transforming growth factor (TGF)-?1 activates the expression of matrix metalloproteinases (MMPs) in fibroblasts. Attachment of these cells to laminin-111 further raises the TGF-?1-induced expression of MMP-3 and MMP-10. Mesenchymal stromal cells (MSC) attach to a variety of extracellular matrix proteins during development and wound healing. We therefore investigated the TGF-?1-regulated expression of MMPs in MSC upon attachment to laminin-111 and type I collagen. The expression of MMPs was determined by quantitative reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay. The TGF-?1 signalling pathways were investigated by immunoblot and by pharmacological blocking of Smad2, MEK/ERK and p38MAPK activities. Overall, TGF-?1 significantly activated the expression of mRNA encoding MMP-3 (p=0.05), MMP-13 (p=0.05) and TIMP-1 (p=0.01) in MSC. Induction of MMP-10 was not significant. In contrast to our observation on fibroblasts, the attachment of MSC to laminin-111 did not affect the TGF-?1-induced expression of MMP-3 and MMP-10. Attachment to type I collagen reduced the TGF-?1-induced secretion of MMP-3 and MMP-10 compared to cells grown on laminin-111 or tissue culture plastic dishes. The expression of MMP-3 was induced by TGF-?1 via Smad2, ERK1/2 and p38MAPK. The expression of MMP-10 was regulated by Smad2 and ERK/1/2, whereas the expression of MMP-13 was shown to be p38 MAPkinase dependent. We conclude that the regulation of MMP-3, MMP-10, and MMP-13 by TGF-?1 proceeds via distinct signalling routes. In contrast to the regulatory pathways in fibroblasts, we could not prove a co-signalling of TGF-?1- and integrin-dependent pathways for the regulation of MMP-3 and MMP-10 in MSC upon attachment to laminin-111. Therefore, MSC respond differently to TGF-?1 and extracellular matrix molecules compared to fibroblasts.