Related Experiment Video
Updated: Sep 26, 2026

Molecular Analysis of Endothelial-mesenchymal Transition Induced by Transforming Growth Factor-β Signaling
Published on: August 3, 2018
Role of Smad4 on TGF-beta-induced extracellular matrix stimulation in mesangial cells
Ken-ichi Tsuchida1, Yanqing Zhu, Senthuran Siva
1Dorrance Hamilton Laboratories, Division of Nephrology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Background:
The best characterized signaling pathway employed by transforming growth factor-beta (TGF-beta) is the Smad pathway; however, its role in matrix production in mesangial cells is unclear. We focused on Smad4, as Smad4 is essential for the activation of Smad-dependent target genes.
Methods:
To investigate the function of Smad4 in extracellular matrix (ECM) production, we generated several stably transfected mesangial cell lines (MMC) that have a deletion in the linker region (Smad4 Delta M4: Delta 275-322) or have a deletion in MH1 of Smad4 (Smad4N4: Delta 1-136). The ECM genes, alpha1 type I collagen (COL1A1), plasminogen activator inhibitor-1 (PAI-1) and fibronectin (FN) were assessed in wild-type mesangial cells and stably transfected Smad4-DN cell lines in the absence and presence of TGF-beta.
Results:
As compared to wild-type MMC that had a 10.8-fold stimulation of TGF-beta-induced p3TP-Lux activity, MMC stably transfected with Smad4 Delta M4 and Smad4N4 had only a 2.0-fold and 1.3-fold stimulation, respectively, indicating that they had dominant-negative effects on TGF-beta signaling. Basal and TGF-beta-induced COL1A1 expression in Smad4 dominant-negative cells were dramatically reduced to very low levels. The early (2 hours) TGF-beta-induced PAI-1 mRNA expression was inhibited; however, the sustained (24 to 48 hours) TGF-beta-induced expression was not affected in Smad4 dominant-negative cells. For FN, TGF-beta-induced expression was maintained in Smad4-dominant negative cells.
Conclusion:
These results indicate that Smad4 is essential for basal and TGF-beta-induced COL1A1 expression, and contributes to the early, but not sustained TGF-beta-induced PAI-1 expression in mesangial cells. However, TGF-beta-induced FN expression is independent of Smad4. In conclusion, Smad4 has a discriminate effect in mediating specific ECM molecules stimulated by TGF-beta in mesangial cells.
More Related Videos
06:54Studying TGF-β Signaling and TGF-β-induced Epithelial-to-mesenchymal Transition in Breast Cancer and Normal Cells
Published on: October 27, 2020
11:38Visualization and Quantification of TGFβ/BMP/SMAD Signaling under Different Fluid Shear Stress Conditions using Proximity-Ligation-Assay
Published on: September 14, 2021
Related Concept Videos
TGF - β Signaling Pathway
Role of Matrix Metalloproteases in Degradation of ECM
A...
The Extracellular Matrix
In order to maintain tissue organization, many animal cells are surrounded by structural molecules that make up the extracellular matrix (ECM). Together, the molecules in the ECM maintain the structural integrity of tissue as well as the remarkable specific properties of certain tissues.
Composition of the Extracellular Matrix
The extracellular matrix (ECM) is commonly composed of ground substance, a gel-like fluid, fibrous components, and many structurally and functionally diverse...
The Extracellular Matrix
Cell-matrix's Response to Mechanical Forces
Anchoring junctions mechanically attach a cell to the...
Intracellular Signaling Affects Focal Adhesions
Some...