Fluid Shear Stress Regulates the Expression of TGF-β1 and Its Signaling Molecules in Mouse Embryo Mesenchymal Progenitor Cells

BackgroundRecently we reported that fluid shear stress promotes endothelial cell differentiation from a mouse embryo mesenchymal progenitor cell line C3H10T1/2. However, it is not clear whether the transforming growth factor-beta 1 (TGF-β1) system is associated with shear-induced endothelial differentiation. The purpose of this study was to determine the effect of shear stress on the expression of TGF-β1 and its signaling molecules in C3H10T1/2 cells.MethodsMurine C3H10T1/2 cells were incubated on collagen Type 1-coated dishes, and subjected to a steady fluid shear stress of 15 dyn/cm2 for 6, 12, and 24 h. The mRNA levels for TGF-β1, TGF-β receptors (TGF-βR), and Smad molecules were determined with real-time PCR analysis and normalized to glyceraldehyde-3-phosphate dehydrogenase mRNA levels.ResultsTGF-β1 mRNA expression was down-regulated by 60% and 66% in shear stress-treated cells at 12 and 24 h, respectively, compared with static control group (P < 0.01). In addition, shear stress significantly decreased TGF-βR1 mRNA levels by 30% and 50% in shear stress-treated cells at 12 and 24 h, respectively (P < 0.01). For TGF-βR2, shear stress at 6, 12, and 24 h significantly reduced its expression by 93%, 95% and 97%, respectively, compared with static controls (P < 0.01). Furthermore, shear stress significant decreased mRNA levels of positive signaling molecules Smad2, Smad3, and Smad4 in a time-dependent manner (P < 0.01). However, shear stress significantly increased negative signaling molecule Smad7 mRNA levels by 100% at 24 h treatment compared with static control group (P < 0.01).ConclusionsFluid shear stress significantly suppresses TGF-β1 functions through down-regulation of TGF-β1, TGF-βR, positive signaling molecules Smad2, Smad3, Smad4, and up-regulation of negative signaling molecule Smad7 in a mouse embryo mesenchymal progenitor cell line C3H10T1/2. This study suggests that the negative regulation of the TGF-β1 system may be involved in shear-induced endothelial cell differentiation in C3H10T1/2.