Premium
Effects of short‐term cyclic tensile strain and TGF‐β1 on smad pathway in human mesenchymal stem cells
Author(s) -
CHEN HUA HUA,
DE ISLA NATALIA,
OUYANG JINGPING,
STOLTZ JEANFRANCOIS
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.706.4
Subject(s) - mesenchymal stem cell , mechanotransduction , chondrogenesis , transforming growth factor , chemistry , smad , microbiology and biotechnology , phosphorylation , stimulation , andrology , endocrinology , biology , medicine , biochemistry
Transforming growth factor‐β (TGF‐β) is a key factor for chondrogenic differentiation of human mesenchymal stem cells (hMSCs). Mechanical loading has also been shown to be important in MSC differentiation, but mechanisms by which mechanotransduction occurs remain largely elusive. In this study, MSCs were obtained from bone marrow samples of healthy donors. MSCs at passage 4 were seeded on an elastic silicone membrane coated with collagen I (BioFlex plate). At 80% confluence, cells were pretreated with serum‐free medium for 24 h. Then chondrogenic medium with or without TGF‐β1was added and cyclic tensile strain (CTS, 0.5 Hz, 5% equibiaxial strain) was applied for 10, 30, 60 and 180 minutes using a Flexercell Tension Plus system (FX‐4000T, Flexcell International). As a control, cells cultured on the same type of plates, without stretch, with or without TGF‐β1 were also used. Using specific antibodies, Smad2/3 and Smad3 phosphorylation (pSmad3) were quantified by western blotting and localization of pSmad3 was observed by confocal microscopy. We have found that, the level of Smad2/3 is not significantly different in all conditions. Both the CTS and TGF‐β1 increased pSmad3 at all times tested. And CTS plus TGF‐β1 exhibited higher level of psmad3 than CTS and TGF‐β1 respectively. However, the increase was maximal at 1 hour of stimulation and decreased after 3 hours of stimulation. Smad3p translocation to the nucleus was observed submitted to CTS and TGF‐β1. Our results show that CTS affected smad3 phosphorylation and that the effect was time dependent. A synergy effect between CTS and TGF‐β1 was observed. CTS could stimulate MSC differentiation by the activation of endogenous TGF‐β signaling pathway.