Fluid shear stress regulates the expression of TGF-beta1 and its signaling molecules in mouse embryo mesenchymal progenitor cells.
BACKGROUND
Recently 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-beta1) 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-beta1 and its signaling molecules in C3H10T1/2 cells.


METHODS
Murine C3H10T1/2 cells were incubated on collagen Type 1-coated dishes, and subjected to a steady fluid shear stress of 15 dyn/cm(2) for 6, 12, and 24 h. The mRNA levels for TGF-beta1, TGF-beta receptors (TGF-beta R), and Smad molecules were determined with real-time PCR analysis and normalized to glyceraldehyde-3-phosphate dehydrogenase mRNA levels.


RESULTS
TGF-beta1 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-beta R1 mRNA levels by 30% and 50% in shear stress-treated cells at 12 and 24 h, respectively (P < 0.01). For TGF-beta R2, 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).


CONCLUSIONS
Fluid shear stress significantly suppresses TGF-beta1 functions through down-regulation of TGF-beta1, TGF-beta R, 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-beta1 system may be involved in shear-induced endothelial cell differentiation in C3H10T1/2.
Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Michael E. DeBakey VA Medical Center, Baylor College of Medicine, Houston, Texas 77030, USA.
Hao
H
Wang
Min
M
Li
Peter H
PH
Lin
Qizhi
Q
Yao
Changyi
C
Chen
D000818:Animals; D002460:Cell Line; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D012333:RNA, Messenger / Q000378:metabolism; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*; D033081:Shear Strength; D051785:Smad Proteins / Q000378:metabolism*; D013314:Stress, Mechanical; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; D051785:Smad Proteins; D053773:Transforming Growth Factor beta1